WO2014103512A1 - Soft tissue cartilage interface detection method, soft tissue cartilage interface detection device, and soft tissue cartilage interface detection program - Google Patents
Soft tissue cartilage interface detection method, soft tissue cartilage interface detection device, and soft tissue cartilage interface detection program Download PDFInfo
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- WO2014103512A1 WO2014103512A1 PCT/JP2013/079826 JP2013079826W WO2014103512A1 WO 2014103512 A1 WO2014103512 A1 WO 2014103512A1 JP 2013079826 W JP2013079826 W JP 2013079826W WO 2014103512 A1 WO2014103512 A1 WO 2014103512A1
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- soft tissue
- echo signal
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- subchondral bone
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
- A61B5/4514—Cartilage
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/08—Detecting organic movements or changes, e.g. tumours, cysts, swellings
- A61B8/0858—Detecting organic movements or changes, e.g. tumours, cysts, swellings involving measuring tissue layers, e.g. skin, interfaces
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/08—Detecting organic movements or changes, e.g. tumours, cysts, swellings
- A61B8/0875—Detecting organic movements or changes, e.g. tumours, cysts, swellings for diagnosis of bone
Definitions
- the present invention relates to a soft tissue cartilage boundary detection method for detecting a boundary surface between cartilage and soft tissue with an ultrasonic wave from the outside.
- the cartilage surface is detected from the difference between the echo signal level of soft tissue (muscle or skin) and the echo signal level of cartilage. Therefore, if there is no difference in the level of the echo signal between soft tissue and cartilage, the cartilage surface cannot be detected accurately.
- the conventional ultrasonic signal does not change suddenly and accurately at the boundary surface between the soft tissue and the cartilage surface, and there is no great difference in the echo signal level at this boundary surface. For this reason, the conventional method cannot accurately detect the cartilage surface.
- An object of the present invention is to provide a soft tissue cartilage boundary surface detecting method capable of accurately detecting a soft tissue and cartilage surface boundary surface in a non-invasive manner.
- the present invention relates to a soft tissue cartilage interface detecting method for detecting a soft tissue / cartilage interface and has the following characteristics.
- the soft tissue cartilage boundary surface detection method includes a first echo signal transmission / reception step, a second echo signal transmission / reception step, a subchondral bone detection step, a movement vector detection step, and a boundary surface detection step.
- an ultrasonic signal is transmitted into the body to be detected in the first state to obtain a first echo signal.
- an ultrasonic signal is transmitted into the body to be detected in the second state to obtain a second echo signal.
- the subchondral bone echo signal in the first state is detected from the first echo signal
- the subchondral bone echo signal in the second state is detected from the second echo signal
- the movement vector detection step detects a movement vector of the subchondral bone from the first state to the second state from the subchondral bone echo signal in the first state and the subchondral bone echo signal in the second state.
- the boundary surface detection step detects the boundary surface between the soft tissue and the cartilage by correcting the sample positions of the echo signals in the first state and the second state based on the movement vector.
- This method utilizes the fact that the cartilage is attached to the subchondral bone, the soft tissue is not attached to the cartilage, and the soft tissue can slide on the cartilage surface.
- the comparison result is soft tissue and cartilage (and Different from subchondral bone).
- the subchondral bone detection step sequentially acquires the signal intensity of the first echo signal along the depth direction, and the signal intensity equal to or higher than the threshold for subchondral bone detection
- the signal in the range in which is detected is detected as a subchondral bone echo signal in the first state.
- the subchondral bone detection step detects the similarity between the subchondral bone echo signal in the first state and the second echo signal, and uses the echo signal having the highest similarity as the subchondral bone echo signal in the second state. To detect.
- the subchondral bone detection step sequentially acquires the signal intensity of the first echo signal from the deep side along the depth direction, and is equal to or greater than the threshold for subchondral bone detection.
- a signal in a range where the signal intensity is detected is detected as a subchondral bone echo signal in the first state.
- the subchondral bone detection step detects the similarity between the subchondral bone echo signal in the first state and the second echo signal, and uses the echo signal having the highest similarity as the subchondral bone echo signal in the second state. To detect.
- an ultrasonic signal is transmitted from the outside of a detected body such as a knee, and the boundary surface between the soft tissue and the cartilage surface is accurately detected while receiving the echo signal outside the detected body. Can do. Thereby, the echo from the cartilage can be accurately detected, and can be effectively used for diagnosis of cartilage.
- FIG. 1 is a block diagram showing a configuration of a soft tissue cartilage boundary detection device 10 according to an embodiment of the present invention. It is a figure which shows the installation aspect with respect to the to-be-detected body of the probe 100 of the soft tissue cartilage boundary detection apparatus 10 which concerns on embodiment of this invention. It is a figure for demonstrating the detection concept of the cartilage surface which concerns on embodiment of this invention. It is a flowchart of the soft tissue cartilage interface detection method which concerns on embodiment of this invention. It is a figure which shows the example of a waveform of each echo signal in 1st state [T1] and 2nd state [T2]. It is a wave form diagram for demonstrating the detection concept of the movement vector which concerns on this embodiment.
- FIG. 6 is a waveform diagram for explaining a method (first method) for detecting whether echo data belongs to cartilage 901 or soft tissue 903;
- FIG. 6 is a waveform diagram for explaining a method (second method) for detecting whether echo data belongs to cartilage 901 or soft tissue 903;
- FIG. 1 is a block diagram showing a configuration of a soft tissue cartilage boundary detection apparatus 10 according to an embodiment of the present invention.
- the present invention can be applied to a case where the probe 100 is brought into contact with and fixed to the knee, which is the detection target, and the knee is bent and stretched.
- the knee which is the detection target
- any method and configuration that can change the positional relationship between soft tissue and cartilage in the first state [T1] and the second state [T2] can be applied.
- FIG. 3 is a diagram for explaining the detection concept of the soft tissue cartilage boundary surface according to the present embodiment.
- FIG. 3 is a view in which the surface of an area where an ultrasonic signal is transmitted and the area in the vicinity thereof are replaced with a flat plane.
- the soft tissue cartilage boundary surface detection apparatus 10 includes an operation unit 11, a transmission control unit 12, an echo signal reception unit 13, a data analysis unit 14, and a probe 100.
- the transmission control unit 12, the echo signal receiving unit 13, and the probe 100 correspond to the “transmission / reception unit” of the present invention.
- the operation unit 11 receives a user operation input.
- the operation unit 11 includes a plurality of operation elements (not shown), and instructs the transmission control unit 12 to start execution of processing for detecting the cartilage surface from a user operation on the operation elements.
- the transmission control unit 12 generates an ultrasonic signal obtained by shaping a carrier wave having an ultrasonic frequency into a pulse shape.
- the transmission control unit 12 generates an ultrasonic signal in each of the first state [T1] and the second state [T2].
- the transmission control unit 12 outputs an ultrasonic signal to the probe 100.
- the probe 100 includes a plurality of transducers arranged in a direction parallel to the transmission / reception surface (see FIG. 3). The direction in which the transducers are arranged is the scanning direction. Each transducer transmits an ultrasonic signal having a predetermined transmission beam angle toward the body to be detected. Each transducer transmits an ultrasonic signal at a predetermined time interval and receives the reflected echo signal.
- the probe 100 is arranged such that the end surface on the wave transmitting / receiving surface side is in contact with the surface of the soft tissue 903 of the knee, which is the detection target.
- the soft tissue 903 is a part of the body including skin and muscles, and is a part that is present on the surface side of the body to be detected with respect to the cartilage 901.
- the cartilage 901 is attached to the subchondral bone 911, and the subchondral bone 911 is a tissue connected to the bone (cancellous bone) 902.
- the probe 100 while moving the probe 100 in contact with the surface of the soft tissue 903 as shown in FIG. 2A, the probe 100 is moved along the surface as shown in FIG. Thereby, as shown in FIG. 2, the soft tissue 903 moves according to the probe 100 while sliding on the surface of the cartilage 901.
- the probe 100 is moved along the arrangement direction (scanning direction) of the transducers.
- Each transducer transmits an ultrasonic signal toward the body to be detected in each of the first state [T1] and the second state [T1]. At this time, each transducer of the probe 100 transmits an ultrasonic signal so that the direction orthogonal to the surface of the soft tissue 903 is the direction of the central axis of the transmission beam.
- Each transducer of the probe 100 receives an echo signal in which an ultrasonic signal is reflected by the soft tissue 903, the cartilage 901, and the subchondral bone 911 in the body to be detected, and outputs the echo signal to the echo signal receiving unit 13.
- the probe 100 includes a first echo group SW [T1] composed of echo signals obtained by each transducer in the first state [T1] and a first echo group SW [T1] composed of echo signals obtained by each transducer in the second state [T2].
- the two echo signal groups SW [T2] are output to the echo signal receiving unit 13, respectively.
- the echo signal receiving unit 13 performs a predetermined amplification process on each echo signal and outputs it to the data analyzing unit 14.
- the echo signal receiving unit 13 individually amplifies each echo signal of the first echo group SW [T1] and each echo signal of the second echo group SW [T2], and outputs the amplified signal to the data analysis unit 14.
- the data analysis unit 14 includes an AD conversion unit 141, a storage unit 142, and a determination unit 143.
- the AD conversion unit 141 converts the echo signal into discrete data by sampling at predetermined time intervals.
- the echo signal converted into discrete data becomes echo data.
- echo data sampled at predetermined intervals in the depth direction for each sweep can be obtained. That is, echo data distributed in a two-dimensional region in the scanning direction and the depth direction can be obtained.
- this echo data group is simply referred to as two-dimensional distribution echo data.
- the AD conversion unit 141 outputs each echo data to the storage unit 142.
- the storage unit 142 stores each echo data output from the AD conversion unit 141.
- the storage unit 142 has a capacity for storing the two-dimensional distribution echo data obtained in the first state and the two-dimensional distribution echo data obtained in the second state.
- the determination unit 143 detects a boundary surface between the soft tissue and the cartilage according to the flow shown in FIG.
- FIG. 4 is a flowchart of the soft tissue cartilage boundary surface detection method according to the embodiment of the present invention.
- the determination unit 143 reads and acquires the two-dimensional distribution echo data obtained in the first state and the two-dimensional distribution echo data obtained in the second state, which are stored in the storage unit 142 (S101). , S102).
- the determination unit 143 obtains echo data of the subchondral bone 911 in the first state (corresponding to the “subchondral bone echo signal in the first state” of the present invention) from the echo data of the two-dimensional distribution in the first state. To detect. The determination unit 143 obtains echo data of the subchondral bone 911 in the second state (corresponding to the “subchondral bone echo signal in the second state” of the present invention) from the two-dimensional distribution echo data in the second state. Detect (S103).
- the determination unit 143 detects the movement vector of the subchondral bone echo data from the subchondral bone echo data in the first state and the subchondral bone echo data in the second state (S104).
- the determining unit 143 aligns the sample data to be compared between the echo data of the two-dimensional distribution in the first state and the echo data of the two-dimensional distribution in the second state based on the movement vector (S105).
- the determination unit 143 calculates a correlation coefficient between the echo data of the first state and the echo data of the second state that are the same comparison target sample positions by the alignment. Specifically, the determination unit 143 sets a comparison target region including a region having a predetermined width in the depth direction including the comparison target sample position. The determination unit 143 calculates a correlation coefficient between the waveform composed of the first state echo data in the comparison target region and the waveform composed of the second state echo data in the comparison target region (S106).
- the determination unit 143 detects a region where comparison target sample positions with a high correlation coefficient are gathered and a region where comparison target sample positions with a low correlation coefficient are gathered, and detects a boundary between these two regions (S107). .
- the cartilage 901 has the same movement mode as the subchondral bone 911, and the soft element 903 has a different movement mode from the subchondral bone 911. For this reason, after the alignment by the movement vector, the echo data of the soft tissue 901 having the same movement mode as the subchondral bone 911 has a high correlation coefficient. On the other hand, after the alignment by the movement vector, the echo data of the soft tissue 901 having a movement mode different from that of the subchondral bone 911 has a low correlation coefficient. Therefore, the boundary surface detected in step S107 is a boundary surface between the soft tissue 903 and the cartilage 901. As described above, the boundary surface between the soft tissue 903 and the cartilage 901 can be detected by using the above-described processing.
- a cartilage diagnosis information generation unit (not shown) can be used for diagnosis of cartilage degeneration based on the cartilage 901 partial echo data. Generate information. Specifically, the information generation unit for cartilage diagnosis acquires a set of echo data near the cartilage surface and echo data of the subchondral bone at a plurality of different times. The cartilage diagnosis information generation unit may detect the amount of change due to the degeneration of the cartilage surface from the transition of the composition of these echo data sets in the time period. The cartilage diagnosis information generation unit outputs the detection result as information that can be used for diagnosis of cartilage degeneration.
- the method for detecting the boundary surface between soft tissue and cartilage executed by the data analysis unit 14 will be described more specifically with reference to the drawings.
- the movement distance ⁇ x of the probe 100 (each transducer) between the first state [T1] and the second state [T2] matches the arrangement interval of the transducers. Will be described.
- the probe 100 is brought into contact with the surface of the knee in a state where the knee that is the detection target is bent at the first angle. In other words, the probe 100 is brought into contact with the surface of the soft tissue 903. This is the state of FIG.
- the plurality of transducers arranged on the probe 100 are arranged at predetermined intervals in a direction parallel to the surface of the soft tissue 903 (scanning direction parallel to the wave transmitting / receiving surface).
- the plurality of transducers transmit ultrasonic signals in a direction orthogonal to the scanning direction.
- five transducers are arranged at equal intervals along the scanning direction in the probe 100, and as shown in FIG.
- the vibrator transmits an ultrasonic signal in a direction orthogonal to the surface of the soft tissue 903.
- the ultrasonic signals transmitted from the respective arrangement positions are reflected at respective depth positions of the soft tissue 903, the cartilage 901, and the subchondral bone 911, received by each transducer, and sampled by the data analysis unit 14.
- the echo data group of the echo data SWT11, SWT12, SWT13, SWT14, and SWT15 received in the first state [T1] becomes the first echo group SW [T1].
- the probe 100 is moved by a distance ⁇ x in a direction parallel to the surface of the soft tissue 903 and in a direction parallel to the scanning direction.
- This state is the second state [T2], which is the state shown in FIG.
- the soft tissue 903 moves following the movement of the probe 100. Therefore, the relative positional relationship between the wave transmitting / receiving surface of the probe 100 and each position in the scanning direction of the soft tissue 903 does not change without depending on the movement of the probe 100.
- the cartilage 901 is fixed to the bone 902 through the subchondral bone 911, it does not move even if the probe 100 moves. Accordingly, the relative positional relationship between the wave transmitting / receiving surface of the probe 100 and the positions of the cartilage 901 and the soft tissue 911 in the scanning direction changes according to the movement of the probe 100.
- an ultrasonic signal is transmitted from each transducer of the probe 100 in a direction orthogonal to the surface of the soft tissue 903 (a direction orthogonal to the transmission / reception surface (scanning direction)).
- the ultrasonic signals transmitted from the respective arrangement positions are reflected at respective depth positions of the soft tissue 903, the cartilage 901, and the subchondral bone 911, received by each transducer, and sampled by the data analysis unit 14.
- the echo data group of the echo data SWT21, SWT22, SWT23, SWT24, and SWT25 received in the second state [T2] becomes the second echo group SW [T2].
- the first echo group SW [T1] including the plurality of echo data SWT11, SWT12, SWT13, SWT14, and SWT15 is acquired before the probe 100 is moved.
- a second echo group SW [T2] including a plurality of echo data SWT21, SWT22, SWT23, SWT24, and SWT25 is acquired.
- FIG. 5 is a diagram illustrating examples of echo waveforms in the first state [T1] and the second state [T2].
- the distance (movement amount) ⁇ x that the probe 100 has moved is assumed to be equal to the interval between the transducers, that is, the interval between the scanning positions, in order to easily illustrate the features of the present invention. In the following, detection of the soft tissue cartilage boundary surface will be described under this condition.
- each echo waveform in the first state [T1] and each echo waveform in the second state [T2] in FIG. 5 regions of the cartilage 901 and the subchondral bone 911 in the first echo group SW [T1]
- the echo data SWT11 of the second echo group SW [T2] does not match the waveform of the cartilage 901 and subchondral bone 911 regions of the echo data SWT21 of the second echo group SW [T2]
- the cartilage of the echo data SWT22 of the second echo group SW [T2] 901 and the subchondral bone 911 regions substantially match the waveform.
- the waveforms of the cartilage 901 and the subchondral bone 911 area of the echo data SWT12 and the areas of the cartilage 901 and the subchondral bone 911 of the echo data SWT23 are substantially the same.
- the waveforms of the cartilage 901 and subchondral bone 911 areas of the echo data SWT13 and the areas of the cartilage 901 and subchondral bone 911 areas of the echo data SWT24 substantially match.
- the waveforms of the cartilage 901 and the subchondral bone 911 in the echo data SWT14 and the areas of the cartilage 901 and the subchondral bone 911 in the echo data SWT25 are substantially the same.
- the echo data at each scanning position is the movement amount ⁇ x in the first state [T1] and the second state [T2], that is, the scanning position is the arrangement interval of the transducers. It is almost the same with the state shifted by one. That is, within the cartilage 901 and the subchondral bone 911, the sample position of each echo data based on the probe 100 changes by the movement amount ⁇ x between the first state [T1] and the second state [T2]. Thus, the cartilage 901 and the subchondral bone 911 are in the same movement mode.
- the echo data SWT11 of the soft tissue 903 region of the first echo group SW [T1] is The waveform of the echo data SWT21 in the soft tissue 903 region of the second echo group SW [T2] is substantially the same.
- the waveforms of the soft tissue 903 area of the echo data SWT12 and the soft tissue 903 area of the echo data SWT22 are substantially the same.
- the waveforms of the soft tissue 903 area of the echo data SWT13 and the soft tissue 903 area of the echo data SWT23 are substantially the same.
- the waveforms of the soft tissue 903 area of the echo data SWT14 and the soft tissue 903 area of the echo data SWT24 are substantially the same.
- the waveforms of the soft tissue 903 area of the echo data SWT15 and the soft tissue 903 area of the echo data SWT25 are substantially the same.
- the echo data at each scanning position in the first state [T1] and the second state [T2] have substantially the same position along the scanning direction with respect to the probe 100. That is, in the soft tissue 903, the sample position of each echo data with the probe 100 as a reference does not change between the first state [T1] and the second state [T2]. For this reason, the movement mode of the echo data of the soft tissue 903 is different from the movement mode in which the sample position of the echo data changes according to the movement of the probe 100 such as the cartilage 901 and the subchondral bone 911 described above.
- the sample position with respect to the probe 100 of the echo data reflected at the specific position (the same in the first state [T1] and the second state [T2]) in the subchondral bone 911 and the cartilage 901 is the first state.
- [T1] and the second state [T2] move along the scanning direction by the movement amount ⁇ x.
- the sample positions of the echo data reflected at a specific position in the soft tissue 903 are the first state [T1] and the second state. [T2] does not change.
- the soft tissue cartilage boundary surface detection apparatus of the present embodiment detects the movement vector of the echo data of the subchondral bone 911 as shown in step S104 described above. Then, as shown in step S105 described above, this movement vector is used to align the sample position of the echo data in the first state [T1] and the sample position of the echo data in the second state [T2]. . In other words, the combination of the sample position of the echo data in the first state [T1] and the sample position of the echo data in the second state [T2] to be compared is determined.
- echo data of the subchondral bone 911 is detected as shown in step S103 described above.
- the echo data of the subchondral bone 911 has a high echo level (amplitude).
- the echo level of the cartilage 901 is high on the cartilage surface, but the echo level is low in the region between the cartilage surface and the subchondral bone 911.
- the echo levels of the echo data SWT11-SWT15 of the first echo group SW [T1] are sequentially acquired along the depth direction. Then, it is detected that the echo level is lower than the subchondral bone detection threshold over a predetermined depth (appropriately set according to the thickness of the cartilage), and then an echo level equal to or higher than the subchondral bone detection threshold is detected. Thereby, the part after this sample position can be detected as echo data of the subchondral bone 911.
- FIG. 6 is a waveform diagram for explaining the concept of detecting a movement vector according to the present embodiment.
- the waveform itself is the same as the waveform diagram of FIG.
- a region of interest Z T1CS is set for the echo data group of the subchondral bone 911 acquired in the first state [T1].
- the attention area Z T1CS is defined by the length in the depth direction (time direction). Specifically, for example, as shown in FIG. 6, in the depth direction (time direction) of one echo data with respect to a two-dimensional region having a scanning direction and a depth direction determined by each echo data SWT11-SWT15. A predetermined range along is set as the attention area Z T1CS . Next, the echo data included in the attention area Z T1CS is extracted. In other words, this corresponds to the waveform of the echo data group cut out in the attention area Z T1CS .
- the echo data SWT21-SWT25 the second echo group SW [T2] sets the search region Z R1.
- the search area Z R1 is determined so as to include echo data in a wider range than the attention area Z T1CS with reference to the position of the attention area Z T1CS with respect to the probe 100.
- the same position as the region of interest ZT1cs is set with respect to the probe 100 by a region expanded by a predetermined range in both the depth direction and the scanning direction with the center in the depth direction and the scanning direction. Is done.
- the center of the attention area Z T1cs is set at the depth position P1cs of the echo signal SWT12
- the search is performed at the depth position P1cs of the echo signal SWT22 in the second state [T2].
- the center of the region Z R1 is set.
- a range longer than the depth direction length of the region of interest is set as the depth direction range of the search region ZR1 .
- the depth position P1cs if within the search region Z R1, may not be the center of the search area Z R1.
- the search area Z R1 is included so as to include the echo data SWT21, SWT22, and SWT23 so that the center in the scanning direction is the echo data SWT22. Set the range in the scanning direction.
- the lower bone comparison target region Z T2CS is set for the echo data group of the subchondral bone 911 acquired in the second state [T2].
- the lower bone comparison target region ZT2cs selects one echo signal and sets it as a region having a predetermined length in the depth direction.
- the depth direction length of the lower bone comparison target region Z T2cs is set to match the depth direction length of the attention region Z T1cs .
- Comparison regions Z T2CS for the lower bone is set to span the entire search area Z R1 which is set as described above. Echo data is acquired for each lower bone comparison target region ZT2CS set in this way.
- a correlation coefficient is calculated by performing a correlation process on the echo data of the attention area Z T1CS and the echo data of the lower bone comparison target area Z T2CS .
- a correlation coefficient for each region of interest Z T1CS detects a comparison regions Z T2CS for the lower bone becomes maximum. This corresponds to the most similar region in the subchondral bone 911 region, and becomes echo data of the subchondral bone 911 in the second state [T2]. In this manner, the echo data of the subchondral bone 911 in the second state [T2] is detected from the similarity of the echo signals.
- a movement vector (movement direction, movement amount) of echo data of the subchondral bone 911 from the first state [T1] to the second state [T2] is detected.
- FIG. 7 is a diagram showing the definition of the movement vector according to the present embodiment.
- FIG. 7 shows a case where the attention area and the lower bone comparison target area are used.
- Moving vector v m is defined from the position of the representative point of the representative point and the lower bone for comparison regions of the region of interest is determined to be most similar to each other.
- Moving vector v m as a starting point a representative point of the region of interest, a vector and terminating the representative point of the comparison regions for the lower bone, is defined by the moving direction and the moving amount.
- the representative point of the region of interest exists at a predetermined depth position on the echo signal SWT11, that is, in the scanning direction position P1.
- the representative point of the lower bone comparison target region exists on the echo signal SWT22, that is, in the scanning direction position P2, at a predetermined depth position.
- the depth position of the representative point of the attention area is the same as the depth position of the representative point of the lower bone comparison target area.
- the movement vector v m is a vector in which the scanning direction is the movement direction and the distance ⁇ x between the scanning positions P1 and P2 is the movement amount.
- Such calculation of the movement vector may be performed on all echo data of the subchondral bone 911 or may be performed on one or more representative echo data.
- the average of the movement vectors calculated for each may be used as the movement vector of the subchondral bone 911.
- FIG. 8 is a diagram showing a distribution state of movement vectors according to the present embodiment.
- the movement vector vm of the echo data in the subchondral bone 911 region is ⁇ x
- the movement vector vm of the echo data in the cartilage 901 region is also ⁇ x.
- the movement vector vm of the echo data of the soft tissue 903 is 0, which is different from the movement vectors of the subchondral bone 911 and the cartilage 901.
- FIG. 9 is a waveform diagram for explaining a method (first method) for detecting whether echo data belongs to cartilage 901 or soft tissue 903.
- a first comparison target area ZT1n is set for the echo data group acquired in the first state [T1] (n is an integer determined from the number of sample positions along the depth direction).
- the first comparison target region ZT1n is defined by the length in the depth direction (time direction).
- the depth direction (time direction) of one echo data with respect to a two-dimensional region having a scanning direction and a depth direction determined by each echo data SWT11-SWT15. ) Is set to the first comparison target area ZT11 .
- the echo data included in the first comparison target area ZT11 is extracted. In other words, this corresponds to the waveform of the echo data group cut out in the first comparison target area ZT11 .
- the first comparison target region ZT11 may be set by excluding the region of the subchondral bone 911, and may be set by excluding the region of the cartilage 901 that is close to the subchondral bone 911 and has a low echo level.
- a second comparison target region ZT2n is set for the echo data group acquired in the second state [T2] (n is an integer determined from the number of sample positions along the depth direction).
- the second comparison target region Z T2n is set at a position where the first comparison target region Z T1n is moved by the movement vector.
- the depth region in the second state [T2] obtained by moving this region with the movement vector is set as the second comparison target region ZT2n . That is, the sample position of the echo data in the first state [T1] to be compared and the sample position of the echo data in the second state [T2] are aligned by the movement vector.
- the first state [T1] echo data SWT12 is set to a predetermined depth position P11.
- one comparison region Z T11 is set at a predetermined depth position P21 of the echo data SWT23 moved by the movement vector ⁇ x from the echo data SWT22 obtained in the second state [T2] of the same vibrator second comparison regions Z T21 is set.
- the same transducer causes the second state [T2].
- the cartilage 901 moves with the same movement vector as the subchondral bone 911, and the movement mode is the same. Therefore, the correlation coefficient between the echo data of the first comparison target region Z T1n and the echo data of the second comparison target region Z T2n aligned by the movement vector is approximately 1. That is, the correlation coefficient becomes high.
- the soft tissue 903 does not move in the same manner as the cartilage 901 and the subchondral bone 911, the movement mode is different. Therefore, the correlation coefficient between the echo data of the first comparison target region Z T1n and the echo data of the second comparison target region Z T2n aligned by the movement vector approaches zero. That is, the correlation coefficient is low.
- the echo data of the first comparison target region ZT12 and the echo data of the second comparison target region ZT22 set in the cartilage 901 have the same waveform, and the correlation coefficient is high.
- the echo data of the first comparison target region Z T11 and the echo data of the second comparison target region Z T21 set in the soft tissue 903 have different waveforms, and the correlation coefficient is low.
- the echo data of the comparison target region having a high correlation coefficient is the echo data in the cartilage 901
- the echo data of the comparison target region having a low correlation coefficient is the echo data in the soft tissue 903. It can be judged.
- each echo is calculated. Whether the data is in soft tissue 903 or cartilage 901 can be detected.
- the boundary surface between the soft tissue 903 and the cartilage 901 can be detected by detecting the boundary between the echo data group determined to be within the soft tissue 903 and the echo data group determined to be within the cartilage 901.
- the example in which the sample area of the echo data acquired in the second state [T2] is moved by the movement vector to set the comparison target region is shown.
- the sample is acquired in the first state [T1].
- the comparison target area may be set by moving the sample position of the echo data based on the movement vector.
- FIG. 10 is a waveform diagram for explaining a method (second method) for detecting whether the echo data belongs to the cartilage 901 or the soft tissue 903.
- the echo data acquired in the second state [T2] is used as a reference.
- a second comparison target region ZT2n is set for the echo data group acquired in the second state [T2] (n is an integer determined from the number of sample positions along the depth direction).
- the depth direction (time direction) of one echo data with respect to a two-dimensional region having a scanning direction and a depth direction determined by each echo data SWT21-SWT25. ) Is set in the second comparison target area ZT21 .
- echo data included in the second comparison target region ZT21 is extracted. In other words, this corresponds to the waveform of the echo data group cut out in the second comparison target region ZT21 .
- the first comparison target region Z T1n is set for the echo data group acquired in the first state [T1] (n is an integer determined from the number of sample positions along the depth direction).
- the first comparison target area Z T1n is set to a position where the second comparison target area Z T2n is moved in the direction opposite to the movement vector and according to the magnitude of the movement vector, based on the movement vector. .
- the second comparison target region Z T2n in the first state [T1] by the same transducer that has obtained the echo data of the first comparison target region Z T2n in the second state [T2]. Detect depth region. Then, the depth region in the first state [T1] obtained by moving this region based on the movement vector is set as the first comparison target region ZT1n . That is, the sample position of the echo data in the first state [T1] is aligned with the sample position of the echo data in the second state [T2] to be compared based on the movement vector.
- the second state [T2] echo data SWT22 in the predetermined depth position P21 when the movement vector ⁇ x that moves only in the scanning direction as described above is obtained, as shown in FIG. 10, the second state [T2] echo data SWT22 in the predetermined depth position P21
- 2 comparison regions Z T21 When 2 comparison regions Z T21 is set, the first compared to a predetermined depth position P11 of the echo data SWT11 moved only in the opposite direction movement vector ⁇ x from the echo data SWT12 which the same oscillator obtained in the first state [T1]
- the target area ZT11 is set.
- the boundary surface between soft tissue and cartilage can be accurately detected non-invasively.
- the norm Norm can be defined by the following equation.
- Ddzt1 (i) is an echo data value of a point at the position i in the depth direction of the first comparison target region ZT1n .
- Ddzt2 (i) is the echo data value at the point in the depth direction position i of the second comparison regions Z T 2 n.
- k corresponds to the resolution of the first comparison area Z T1n and second comparison regions Z T 2 n, the total number of echo data contained in the first comparison region Z T1n and second comparison regions Z T 2 n.
- m is an appropriately set constant.
- the norm Norm raises the absolute value of the difference between the echo data at the same position in the first comparison target region Z T1n and the second comparison target region Z T2n to the nth power, and adds the nth power value over the entire region. , 1 / nth power. Accordingly, a first comparison area Z T1n and the second comparison region Z T 2 n norm Norm higher similarity decreases, the more the norm Norm similarity is low is increased.
- the first comparison target region Z T1n and the second comparison target region Z T2n having a small norm correspond to a case where the correlation coefficient is high, and can be determined to be within the cartilage 901.
- the first comparison target region Z T1n and the second comparison target region Z T2n having a large norm correspond to the case where the correlation coefficient is low, and can be determined to be in the soft tissue 903.
- Such a method using the norm can also be used when detecting the movement vector of the subchondral bone 911. Specifically, to detect the most norm Norm small for the lower bone comparison regions Z T2CS for the target region Z T1CS.
- the movement vector can be detected by calculating a vector starting from the representative position of the attention area Z T1CS of the combination having the minimum norm Norm and starting from the representative position of the lower bone comparison target area Z T2CS. it can.
- each process for cartilage surface detection is realized by a plurality of functional blocks.
- the above-described cartilage surface detection process may be programmed and stored, and the program may be read and executed by a computer.
- the relative positional relationship between the probe 100 and the soft tissue 903, the cartilage 901, and the subchondral bone 911 may be changed by fixing the probe 100 and bending the knee with a jig or the like.
- transducers are arranged and arranged along only one direction of the scanning direction.
- the transducers may be arranged at a predetermined interval in a two-dimensional region of the scanning direction and the direction orthogonal to the scanning direction and the depth direction.
- FIG. 11 is a diagram showing a detection configuration by mechanical scanning for moving the transducer.
- the mechanical scan type probe 100A includes a transducer having a vibrator.
- the transducer is installed so as to be movable along the scanning axis.
- the transducer moves along the scan axis.
- the transducer of the transducer transmits an ultrasonic signal in a direction orthogonal to the scanning direction. While moving this transducer in the scanning direction, it stops at a plurality of scanning positions, transmits an ultrasonic signal, and receives the echo signal, thereby obtaining the same echo signal as the probe 100 having a plurality of transducers. be able to.
- the subchondral bone detection method in the first state [T1] is not limited to the method of comparing the echo level with the threshold value in order from the depth side, but the echo level is set in order from the depth side.
- a method of comparing with a threshold value may be used. Specifically, since the echo attenuation amount is large inside the bone inside the subchondral bone, the echo level is substantially zero. Therefore, the threshold value is set to a predetermined value larger than approximately zero. Then, the echo level is compared with a threshold value from the deep side, that is, the inside of the bone, and echo data at a position where the echo level is equal to or higher than the threshold value is acquired as echo data of the subchondral bone.
- the similarity with the echo signal in the first state [T1] is used.
- the second state [T2] Similarly to the detection of the subchondral bone echo signal in the first state [T1], the subchondral bone echo signal may be compared with a threshold value.
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Abstract
[Problem] To accurate detect boundaries between soft tissue and cartilage non-invasively. [Solution] Echo data for first and second states are acquired (S101 and S102). On the basis of the echo data for the first and second states, echo data for a subchondral bone (911) in the first state and the second state are detected (S103). On the basis of the subchondral bone echo data for the first state and the second state, movement vectors for the subchondral bone echo data are detected (S104). On the basis of the movement vectors, alignment is performed between sample data for comparison of the echo data for the first state and the echo data for the second state (S105). Correlation coefficients for the echo data for the first state and the echo data for the second state, which are to be identical sample positions for comparison by way of alignment, are calculated (S106). Determinations are made of areas of high coefficients as cartilage and areas of low coefficients as soft tissue, and interfaces therebetween are detected (S107).
Description
本発明は、軟骨と軟組織との境界面を、外部からの超音波で検出する軟組織軟骨境界検出方法に関する。
The present invention relates to a soft tissue cartilage boundary detection method for detecting a boundary surface between cartilage and soft tissue with an ultrasonic wave from the outside.
従来、軟骨の状態を診断するための情報を生成する装置が、各種考案されている。例えば、特許文献1の超音波診断装置では、超音波を送受波するプローブを、膝の表面に当接させ、当該プローブで得た膝内部からのエコー信号で、軟骨の状態を診断している。すなわち、特許文献1の超音波診断装置は、非侵襲で軟骨の状態を診断している。そして、特許文献1の超音波診断装置では、深度方向のエコー信号のレベル(強度)の差から、軟骨を検出している。
Conventionally, various devices for generating information for diagnosing the state of cartilage have been devised. For example, in the ultrasonic diagnostic apparatus of Patent Document 1, a probe that transmits and receives ultrasonic waves is brought into contact with the surface of the knee, and the state of the cartilage is diagnosed with an echo signal from the inside of the knee obtained by the probe. . That is, the ultrasonic diagnostic apparatus of Patent Document 1 diagnoses the state of cartilage noninvasively. And in the ultrasonic diagnostic apparatus of patent document 1, the cartilage is detected from the level (intensity) difference of the echo signal of a depth direction.
しかしながら、特許文献1の装置および方法では、軟組織(筋肉や皮膚)のエコー信号レベルと軟骨のエコー信号レベルとの差から、軟骨表面を検出している。したがって、軟組織と軟骨とで、エコー信号のレベルに差が無ければ、軟骨表面を正確に検出することができない。
However, in the apparatus and method of Patent Document 1, the cartilage surface is detected from the difference between the echo signal level of soft tissue (muscle or skin) and the echo signal level of cartilage. Therefore, if there is no difference in the level of the echo signal between soft tissue and cartilage, the cartilage surface cannot be detected accurately.
そして、概ね従来の超音波信号では、軟組織と軟骨表面との境界面で急激に且つ正確にエコー信号レベルが変化するわけではなく、この境界面においてエコー信号レベルに大きな差が無い。このため、従来の方法では、軟骨表面を正確に検出することができない。
And generally, in the conventional ultrasonic signal, the echo signal level does not change suddenly and accurately at the boundary surface between the soft tissue and the cartilage surface, and there is no great difference in the echo signal level at this boundary surface. For this reason, the conventional method cannot accurately detect the cartilage surface.
本発明の目的は、非侵襲で軟組織と軟骨表面の境界面を正確に検出できる軟組織軟骨境界面検出方法を提供することにある。
An object of the present invention is to provide a soft tissue cartilage boundary surface detecting method capable of accurately detecting a soft tissue and cartilage surface boundary surface in a non-invasive manner.
この発明は、軟組織と軟骨の境界面を検出する軟組織軟骨境界面検出方法に関するものであって、次の特徴を有する。軟組織軟骨境界面検出方法は、第1エコー信号送受信工程、第2エコー信号送受信工程、軟骨下骨検出工程、移動ベクトル検出工程、および、境界面検出工程を有する。
The present invention relates to a soft tissue cartilage interface detecting method for detecting a soft tissue / cartilage interface and has the following characteristics. The soft tissue cartilage boundary surface detection method includes a first echo signal transmission / reception step, a second echo signal transmission / reception step, a subchondral bone detection step, a movement vector detection step, and a boundary surface detection step.
第1エコー信号送受信工程は、第1の状態で超音波信号を被検知体内に送信して第1のエコー信号を得る。第2エコー信号送受信工程は、第2の状態で超音波信号を被検知体内に送信して第2のエコー信号を得る。
In the first echo signal transmission / reception step, an ultrasonic signal is transmitted into the body to be detected in the first state to obtain a first echo signal. In the second echo signal transmission / reception step, an ultrasonic signal is transmitted into the body to be detected in the second state to obtain a second echo signal.
軟骨下骨検出工程は、第1のエコー信号から第1の状態の軟骨下骨エコー信号を検出し、第2のエコー信号から第2の状態の軟骨下骨エコー信号を検出する。
In the subchondral bone detection step, the subchondral bone echo signal in the first state is detected from the first echo signal, and the subchondral bone echo signal in the second state is detected from the second echo signal.
移動ベクトル検出工程は、第1の状態の軟骨下骨エコー信号と第2の状態の軟骨下骨エコー信号とから、第1の状態から第2の状態への軟骨下骨の移動ベクトルを検出する。
The movement vector detection step detects a movement vector of the subchondral bone from the first state to the second state from the subchondral bone echo signal in the first state and the subchondral bone echo signal in the second state. .
境界面検出工程は、移動ベクトルに基づいて第1の状態と第2の状態のエコー信号のサンプル位置を補正して、軟組織と軟骨の境界面を検出する。
The boundary surface detection step detects the boundary surface between the soft tissue and the cartilage by correcting the sample positions of the echo signals in the first state and the second state based on the movement vector.
この方法では、軟骨が軟骨下骨に付着しており、軟組織が軟骨に付着しておらず軟組織が軟骨表面を横滑りできるようになっていることを利用している。
This method utilizes the fact that the cartilage is attached to the subchondral bone, the soft tissue is not attached to the cartilage, and the soft tissue can slide on the cartilage surface.
超音波信号を送信するプローブを被検知体に接触させて移動させると、軟組織は追随し、軟骨および軟骨下骨は追随しない。したがって、プローブに対する軟骨下骨の位置変化と軟骨の位置変化とは一致し、移動ベクトルに相当するが、これらの位置変化とプローブに対する軟組織の位置変化とは一致しない。また、プローブを被検知体に接触させた状態で、軟組織と軟骨および軟骨がある被検知体側を屈曲させても、同様に、プローブに対する軟骨下骨の位置変化と軟骨の位置変化とは一致し、プローブに対する軟骨下骨の位置変化と軟組織の位置変化とは一致しない。
When a probe that transmits an ultrasonic signal is moved in contact with a body to be detected, soft tissue follows, but cartilage and subchondral bone do not follow. Therefore, the position change of the subchondral bone with respect to the probe and the position change of the cartilage correspond to the movement vector, but these position changes do not match the position change of the soft tissue with respect to the probe. In addition, even if the detected body side where soft tissue, cartilage, and cartilage are bent is bent while the probe is in contact with the detected object, the change in the position of the subchondral bone relative to the probe and the change in the position of the cartilage are the same. The change in the position of the subchondral bone relative to the probe does not match the change in the position of the soft tissue.
したがって、移動ベクトルによって第1の状態のエコー信号のサンプル位置と第2の状態のエコー信号のサンプル位置を補正して、各サンプル位置のエコー信号を比較すれば、比較結果が軟組織と軟骨(および軟骨下骨)とで異なる。この異なる点を利用することで、軟組織と軟骨とを判別でき、軟組織と軟骨との境界面を検出できる。
Therefore, if the sample position of the echo signal in the first state and the sample position of the echo signal in the second state are corrected by the movement vector, and the echo signal at each sample position is compared, the comparison result is soft tissue and cartilage (and Different from subchondral bone). By utilizing this different point, it is possible to distinguish soft tissue and cartilage and to detect the boundary surface between soft tissue and cartilage.
また、この発明の軟組織軟骨境界面検出方法では、軟骨下骨検出工程は、第1のエコー信号の信号強度を深度方向に沿って順次取得していき、軟骨下骨検出用閾値以上の信号強度を検出した範囲の信号を、第1の状態の軟骨下骨エコー信号として検出する。軟骨下骨検出工程は、第1の状態の軟骨下骨エコー信号と第2のエコー信号との類似度を検出し、最も類似度の高いエコー信号を第2の状態の軟骨下骨エコー信号として検出する。
In the soft tissue cartilage boundary surface detection method of the present invention, the subchondral bone detection step sequentially acquires the signal intensity of the first echo signal along the depth direction, and the signal intensity equal to or higher than the threshold for subchondral bone detection The signal in the range in which is detected is detected as a subchondral bone echo signal in the first state. The subchondral bone detection step detects the similarity between the subchondral bone echo signal in the first state and the second echo signal, and uses the echo signal having the highest similarity as the subchondral bone echo signal in the second state. To detect.
また、この発明の軟組織軟骨境界面検出方法では、軟骨下骨検出工程は、第1のエコー信号の信号強度を深度方向に沿って深部側から順次取得していき、軟骨下骨検出用閾値以上の信号強度を検出した範囲の信号を、第1の状態の軟骨下骨エコー信号として検出する。軟骨下骨検出工程は、第1の状態の軟骨下骨エコー信号と第2のエコー信号との類似度を検出し、最も類似度の高いエコー信号を第2の状態の軟骨下骨エコー信号として検出する。
In the soft tissue cartilage boundary surface detection method of the present invention, the subchondral bone detection step sequentially acquires the signal intensity of the first echo signal from the deep side along the depth direction, and is equal to or greater than the threshold for subchondral bone detection. A signal in a range where the signal intensity is detected is detected as a subchondral bone echo signal in the first state. The subchondral bone detection step detects the similarity between the subchondral bone echo signal in the first state and the second echo signal, and uses the echo signal having the highest similarity as the subchondral bone echo signal in the second state. To detect.
これらの方法では、軟骨下骨の具体的な検出方法を示している。
These methods show specific detection methods for subchondral bone.
この発明によれば、膝等の被検知体の外部から超音波信号を送信し、そのエコー信号を被検知体の外部で受信しながら、軟組織と軟骨表面との境界面を正確に検出することができる。これにより、軟骨からのエコーを正確に検出することができ、軟骨の診断に効果的に利用することができる。
According to the present invention, an ultrasonic signal is transmitted from the outside of a detected body such as a knee, and the boundary surface between the soft tissue and the cartilage surface is accurately detected while receiving the echo signal outside the detected body. Can do. Thereby, the echo from the cartilage can be accurately detected, and can be effectively used for diagnosis of cartilage.
本発明の実施形態に係る軟組織軟骨境界面検出方法および軟組織軟骨境界面検出装置について、図を参照して説明する。図1は本発明の実施形態に係る軟組織軟骨境界検出装置10の構成を示すブロック図である。図2は、本実施形態に係る軟組織軟骨境界検出装置10のプローブ100の被検知体に対する設置態様を示す図であり、図2(A)は第1状態(t=T1)の場合を示し、図2(B)は第2状態(t=T2)の場合を示す。なお、以下の説明では、プローブ100を移動させる例を示したが、被検知体を動かす場合にも、以下の方法や構成を適用できる。例えば、被検知体である膝にプローブ100を当接して固定し、膝を屈伸させるような場合であっても、適用できる。すなわち、第1状態[T1]と第2状態[T2]とにおいて、軟組織と軟骨との位置関係が変化するような方法および構成であれば適用できる。
A soft tissue cartilage boundary surface detection method and a soft tissue cartilage boundary surface detection apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a soft tissue cartilage boundary detection apparatus 10 according to an embodiment of the present invention. FIG. 2 is a diagram showing an installation aspect of the probe 100 of the soft tissue cartilage boundary detection device 10 according to the present embodiment with respect to the detection target, and FIG. 2 (A) shows a case of the first state (t = T1), FIG. 2B shows the case of the second state (t = T2). In the following description, an example in which the probe 100 is moved has been shown, but the following method and configuration can also be applied when moving the detection target. For example, the present invention can be applied to a case where the probe 100 is brought into contact with and fixed to the knee, which is the detection target, and the knee is bent and stretched. In other words, any method and configuration that can change the positional relationship between soft tissue and cartilage in the first state [T1] and the second state [T2] can be applied.
図3は、本実施形態に係る軟組織軟骨境界面の検出概念を説明するための図であり、図3(A)は第1状態[T1](t=T1)を示し、図3(B)は第2状態[T2](t=T2)を示す。図3は、超音波信号が送信される領域およびその近傍領域の表面を平坦な平面に置き換えて見たものである。
FIG. 3 is a diagram for explaining the detection concept of the soft tissue cartilage boundary surface according to the present embodiment. FIG. 3 (A) shows the first state [T1] (t = T1), and FIG. 3 (B). Indicates the second state [T2] (t = T2). FIG. 3 is a view in which the surface of an area where an ultrasonic signal is transmitted and the area in the vicinity thereof are replaced with a flat plane.
軟組織軟骨境界面検出装置10は、操作部11、送信制御部12、エコー信号受信部13、データ解析部14、およびプローブ100を備える。送信制御部12、エコー信号受信部13およびプローブ100が、本発明の「送受信部」に相当する。
The soft tissue cartilage boundary surface detection apparatus 10 includes an operation unit 11, a transmission control unit 12, an echo signal reception unit 13, a data analysis unit 14, and a probe 100. The transmission control unit 12, the echo signal receiving unit 13, and the probe 100 correspond to the “transmission / reception unit” of the present invention.
操作部11は、ユーザの操作入力を受け付ける。例えば、操作部11は、複数の操作子(図示せず)を備え、操作子に対するユーザの操作から、軟骨表面を検出する処理の実行開始を送信制御部12へ指示する。
The operation unit 11 receives a user operation input. For example, the operation unit 11 includes a plurality of operation elements (not shown), and instructs the transmission control unit 12 to start execution of processing for detecting the cartilage surface from a user operation on the operation elements.
送信制御部12は、超音波の周波数からなる搬送波をパルス状に波形成形した超音波信号を生成する。送信制御部12は、第1状態[T1]と第2状態[T2]のそれぞれで、超音波信号を生成する。
The transmission control unit 12 generates an ultrasonic signal obtained by shaping a carrier wave having an ultrasonic frequency into a pulse shape. The transmission control unit 12 generates an ultrasonic signal in each of the first state [T1] and the second state [T2].
送信制御部12は、超音波信号をプローブ100へ出力する。プローブ100は、送受波面に平行な方向へ配列された複数の振動子を備える(図3参照)。この振動子の配列方向が走査方向となる。各振動子は、所定の送信ビーム角からなる超音波信号を、被検知体内に向けて送信する。各振動子は、所定の時間間隔で超音波信号を送信し、その反射エコー信号を受信する。
The transmission control unit 12 outputs an ultrasonic signal to the probe 100. The probe 100 includes a plurality of transducers arranged in a direction parallel to the transmission / reception surface (see FIG. 3). The direction in which the transducers are arranged is the scanning direction. Each transducer transmits an ultrasonic signal having a predetermined transmission beam angle toward the body to be detected. Each transducer transmits an ultrasonic signal at a predetermined time interval and receives the reflected echo signal.
プローブ100は、具体的には、図2に示すように、被検知体である膝の軟組織903の表面に、送受波面側の端面が当接するように配置される。ここで、図3に示すように、軟組織903とは、皮膚および筋肉を含む体内部分であり、軟骨901よりも被検知体の表面側に存在する部位である。軟骨901は、軟骨下骨911に付着しており、軟骨下骨911は、骨(海綿骨)902に結合した組織である。
Specifically, as shown in FIG. 2, the probe 100 is arranged such that the end surface on the wave transmitting / receiving surface side is in contact with the surface of the soft tissue 903 of the knee, which is the detection target. Here, as shown in FIG. 3, the soft tissue 903 is a part of the body including skin and muscles, and is a part that is present on the surface side of the body to be detected with respect to the cartilage 901. The cartilage 901 is attached to the subchondral bone 911, and the subchondral bone 911 is a tissue connected to the bone (cancellous bone) 902.
図2(A)に示すようにプローブ100を軟組織903の表面に接触させながら、図2(B)に示すようにプローブ100を表面に沿って移動させる。これにより、図2に示すように、軟組織903は、軟骨901の表面を滑りながら、プローブ100に従って移動する。このプローブ100を移動させる前の図2(A)の状態が第1状態(t=T1)であり、プローブ100を移動させた後の図2(B)の状態が第2状態(t=T2)である。この際、プローブ100は振動子の配列方向(走査方向)に沿って移動させる。
2A while moving the probe 100 in contact with the surface of the soft tissue 903 as shown in FIG. 2A, the probe 100 is moved along the surface as shown in FIG. Thereby, as shown in FIG. 2, the soft tissue 903 moves according to the probe 100 while sliding on the surface of the cartilage 901. The state of FIG. 2A before the probe 100 is moved is the first state (t = T1), and the state of FIG. 2B after the probe 100 is moved is the second state (t = T2). ). At this time, the probe 100 is moved along the arrangement direction (scanning direction) of the transducers.
各振動子は、第1状態[T1]と第2状態[T1]のそれぞれにおいて、超音波信号を被検知体内に向けて送信する。この際、プローブ100の各振動子は、軟組織903の表面に対して直交する方向が送信ビームの中心軸の方向となるように、超音波信号を送信する。
Each transducer transmits an ultrasonic signal toward the body to be detected in each of the first state [T1] and the second state [T1]. At this time, each transducer of the probe 100 transmits an ultrasonic signal so that the direction orthogonal to the surface of the soft tissue 903 is the direction of the central axis of the transmission beam.
プローブ100の各振動子は、超音波信号が被検知体内の軟組織903、軟骨901および軟骨下骨911で反射したエコー信号を受信し、エコー信号受信部13へ出力する。プローブ100は、第1状態[T1]において各振動子で得られたエコー信号からなる第1エコー群SW[T1]と、第2状態[T2]において各振動子で得られたエコー信号から第2エコー信号群SW[T2]を、それぞれエコー信号受信部13へ出力する。
Each transducer of the probe 100 receives an echo signal in which an ultrasonic signal is reflected by the soft tissue 903, the cartilage 901, and the subchondral bone 911 in the body to be detected, and outputs the echo signal to the echo signal receiving unit 13. The probe 100 includes a first echo group SW [T1] composed of echo signals obtained by each transducer in the first state [T1] and a first echo group SW [T1] composed of echo signals obtained by each transducer in the second state [T2]. The two echo signal groups SW [T2] are output to the echo signal receiving unit 13, respectively.
エコー信号受信部13は、各エコー信号に対して所定の増幅処理を行い、データ解析部14へ出力する。エコー信号受信部13は、第1エコー群SW[T1]の各エコー信号と、第2エコー群SW[T2]の各エコー信号を、個別に増幅処理して、データ解析部14へ出力する。
The echo signal receiving unit 13 performs a predetermined amplification process on each echo signal and outputs it to the data analyzing unit 14. The echo signal receiving unit 13 individually amplifies each echo signal of the first echo group SW [T1] and each echo signal of the second echo group SW [T2], and outputs the amplified signal to the data analysis unit 14.
データ解析部14は、AD変換部141、記憶部142、判定部143を備える。AD変換部141は、エコー信号を所定の時間間隔でサンプリングすることで、離散データ化する。この離散データ化されたエコー信号がエコーデータとなる。これにより、スイープ毎に深度方向に所定間隔でデータサンプリングされたエコーデータを得ることができる。すなわち、走査方向と深度方向による二次元領域に分布されたエコーデータを得ることができる。以下では、このエコーデータ群を、単に、二次元分布のエコーデータと称する。AD変換部141は、各エコーデータを記憶部142へ出力する。
The data analysis unit 14 includes an AD conversion unit 141, a storage unit 142, and a determination unit 143. The AD conversion unit 141 converts the echo signal into discrete data by sampling at predetermined time intervals. The echo signal converted into discrete data becomes echo data. Thereby, echo data sampled at predetermined intervals in the depth direction for each sweep can be obtained. That is, echo data distributed in a two-dimensional region in the scanning direction and the depth direction can be obtained. Hereinafter, this echo data group is simply referred to as two-dimensional distribution echo data. The AD conversion unit 141 outputs each echo data to the storage unit 142.
記憶部142は、AD変換部141から出力された各エコーデータを記憶する。記憶部142は、第1状態で得られた二次元分布のエコーデータと、第2状態で得られた二次元分布のエコーデータとを記憶する容量を備える。
The storage unit 142 stores each echo data output from the AD conversion unit 141. The storage unit 142 has a capacity for storing the two-dimensional distribution echo data obtained in the first state and the two-dimensional distribution echo data obtained in the second state.
判定部143は、具体的な処理方法は後述するが、図4に示すフローにしたがって、軟組織と軟骨との境界面を検出する。図4は本発明の実施形態に係る軟組織軟骨境界面検出方法のフローチャートである。
The determination unit 143 detects a boundary surface between the soft tissue and the cartilage according to the flow shown in FIG. FIG. 4 is a flowchart of the soft tissue cartilage boundary surface detection method according to the embodiment of the present invention.
判定部143は、記憶部142に記憶されている第1状態で得られた二次元分布のエコーデータと、第2状態で得られた二次元分布のエコーデータとを読み出して、取得する(S101,S102)。
The determination unit 143 reads and acquires the two-dimensional distribution echo data obtained in the first state and the two-dimensional distribution echo data obtained in the second state, which are stored in the storage unit 142 (S101). , S102).
判定部143は、第1状態の二次元分布のエコーデータから、第1状態での軟骨下骨911のエコーデータ(本発明の「第1状態の軟骨下骨エコー信号」に相当する。)を検出する。判定部143は、第2状態の二次元分布のエコーデータから、第2状態での軟骨下骨911のエコーデータ(本発明の「第2状態の軟骨下骨エコー信号」に相当する。)を検出する(S103)。
The determination unit 143 obtains echo data of the subchondral bone 911 in the first state (corresponding to the “subchondral bone echo signal in the first state” of the present invention) from the echo data of the two-dimensional distribution in the first state. To detect. The determination unit 143 obtains echo data of the subchondral bone 911 in the second state (corresponding to the “subchondral bone echo signal in the second state” of the present invention) from the two-dimensional distribution echo data in the second state. Detect (S103).
判定部143は、第1状態の軟骨下骨エコーデータと第2状態の軟骨下骨エコーデータとから軟骨下骨エコーデータの移動ベクトルを検出する(S104)。
The determination unit 143 detects the movement vector of the subchondral bone echo data from the subchondral bone echo data in the first state and the subchondral bone echo data in the second state (S104).
判定部143は、移動ベクトルに基づいて、第1状態の二次元分布のエコーデータと第2状態の二次元分布のエコーデータとの比較対象のサンプルデータの位置合わせを行う(S105)。
The determining unit 143 aligns the sample data to be compared between the echo data of the two-dimensional distribution in the first state and the echo data of the two-dimensional distribution in the second state based on the movement vector (S105).
判定部143は、位置あわせによって同一の比較対象サンプル位置となる第1状態のエコーデータと第2状態のエコーデータとの相関係数を算出する。具体的には、判定部143は、比較対象サンプル位置を含み深度方向に所定幅の領域からなる比較対象領域を設定する。判定部143は、比較対象領域内における第1状態のエコーデータからなる波形と、比較対象領域内における第2状態のエコーデータからなる波形の相関係数を算出する(S106)。
The determination unit 143 calculates a correlation coefficient between the echo data of the first state and the echo data of the second state that are the same comparison target sample positions by the alignment. Specifically, the determination unit 143 sets a comparison target region including a region having a predetermined width in the depth direction including the comparison target sample position. The determination unit 143 calculates a correlation coefficient between the waveform composed of the first state echo data in the comparison target region and the waveform composed of the second state echo data in the comparison target region (S106).
判定部143は、相関係数が高い比較対象サンプル位置の集合する領域と、相関係数が低い比較対象サンプル位置の集合する領域とを検出し、これら2つの領域の境界を検出する(S107)。
The determination unit 143 detects a region where comparison target sample positions with a high correlation coefficient are gathered and a region where comparison target sample positions with a low correlation coefficient are gathered, and detects a boundary between these two regions (S107). .
上述のように、軟骨901は軟骨下骨911と同じ移動態様となり、軟素子903は、軟骨下骨911と異なる移動態様となる。このため、移動ベクトルによる位置合わせ後においては、軟骨下骨911と同じ移動態様からなる軟組織901のエコーデータは相関係数が高くなる。一方、移動ベクトルによる位置合わせ後においては、軟骨下骨911と異なる移動態様からなる軟組織901のエコーデータは相関係数が低くなる。したがって、ステップS107で検出した境界面は、軟組織903と軟骨901との境界面となる。このように、上述の処理を用いることで、軟組織903と軟骨901との境界面を検出することができる。
As described above, the cartilage 901 has the same movement mode as the subchondral bone 911, and the soft element 903 has a different movement mode from the subchondral bone 911. For this reason, after the alignment by the movement vector, the echo data of the soft tissue 901 having the same movement mode as the subchondral bone 911 has a high correlation coefficient. On the other hand, after the alignment by the movement vector, the echo data of the soft tissue 901 having a movement mode different from that of the subchondral bone 911 has a low correlation coefficient. Therefore, the boundary surface detected in step S107 is a boundary surface between the soft tissue 903 and the cartilage 901. As described above, the boundary surface between the soft tissue 903 and the cartilage 901 can be detected by using the above-described processing.
なお、軟骨901の表面(軟組織903と軟骨901との境界面)が検出されると、図示しない軟骨診断用情報生成部は、軟骨901部分エコーデータに基づいて、軟骨変性の診断に利用可能な情報を生成する。具体的には、軟骨診断用情報生成部は、軟骨表面付近のエコーデータと軟骨下骨のエコーデータとの組を、異なる複数の時期に取得する。軟骨診断用情報生成部は、これらのエコーデータの組の組成の時期間における遷移から、軟骨表面の変性に起因する変化量を検出するなどしてもよい。軟骨診断用情報生成部は、この検出結果を、軟骨変性の診断に利用可能な情報として出力する。
When the surface of the cartilage 901 (the boundary surface between the soft tissue 903 and the cartilage 901) is detected, a cartilage diagnosis information generation unit (not shown) can be used for diagnosis of cartilage degeneration based on the cartilage 901 partial echo data. Generate information. Specifically, the information generation unit for cartilage diagnosis acquires a set of echo data near the cartilage surface and echo data of the subchondral bone at a plurality of different times. The cartilage diagnosis information generation unit may detect the amount of change due to the degeneration of the cartilage surface from the transition of the composition of these echo data sets in the time period. The cartilage diagnosis information generation unit outputs the detection result as information that can be used for diagnosis of cartilage degeneration.
次に、データ解析部14で実行される軟組織と軟骨との境界面の検出方法を、より具体的に図を参照して説明する。なお、説明を簡単にするために、第1状態[T1]と第2状態[T2]との間でのプローブ100(各振動子)の移動距離Δxは、振動子の配置間隔に一致したものとして説明する。
Next, the method for detecting the boundary surface between soft tissue and cartilage executed by the data analysis unit 14 will be described more specifically with reference to the drawings. In order to simplify the explanation, the movement distance Δx of the probe 100 (each transducer) between the first state [T1] and the second state [T2] matches the arrangement interval of the transducers. Will be described.
まず、第1状態[T1]として、例えば、被検知体である膝を第1の角度で曲げた状態で、プローブ100を膝の表面に当接させる。言い換えれば、プローブ100を軟組織903の表面に当接させる。これは、図3(A)の状態である。
First, as the first state [T1], for example, the probe 100 is brought into contact with the surface of the knee in a state where the knee that is the detection target is bent at the first angle. In other words, the probe 100 is brought into contact with the surface of the soft tissue 903. This is the state of FIG.
プローブ100に配置された複数の振動子は、それぞれ軟組織903の表面に平行な方向(送受波面に平行な走査方向)に所定間隔で配置されている。複数の振動子は、走査方向に直交する方向へ超音波信号を送信する。図3の例であれば、プローブ100には、五個の振動子が走査方向に沿って等間隔で配置されており、図3(A)に示すように、それぞれの位置に配置された各振動子は、軟組織903の表面に直交する方向へ超音波信号を送信する。この各配置位置から送信された超音波信号は、軟組織903や軟骨901、軟骨下骨911の各深度位置で反射し、各振動子によって受信され、データ解析部14でサンプリングされる。この第1状態[T1]で受信したエコーデータSWT11,SWT12,SWT13,SWT14,SWT15のエコーデータ群が第1エコー群SW[T1]となる。
The plurality of transducers arranged on the probe 100 are arranged at predetermined intervals in a direction parallel to the surface of the soft tissue 903 (scanning direction parallel to the wave transmitting / receiving surface). The plurality of transducers transmit ultrasonic signals in a direction orthogonal to the scanning direction. In the example of FIG. 3, five transducers are arranged at equal intervals along the scanning direction in the probe 100, and as shown in FIG. The vibrator transmits an ultrasonic signal in a direction orthogonal to the surface of the soft tissue 903. The ultrasonic signals transmitted from the respective arrangement positions are reflected at respective depth positions of the soft tissue 903, the cartilage 901, and the subchondral bone 911, received by each transducer, and sampled by the data analysis unit 14. The echo data group of the echo data SWT11, SWT12, SWT13, SWT14, and SWT15 received in the first state [T1] becomes the first echo group SW [T1].
次に、プローブ100を軟組織903に当接させたままの状態で、プローブ100を軟組織903の表面に平行な方向で且つ走査方向に平行な方向へ、距離Δxだけ移動させる。この状態が第2状態[T2]であり、図3(B)の状態である。
Next, with the probe 100 kept in contact with the soft tissue 903, the probe 100 is moved by a distance Δx in a direction parallel to the surface of the soft tissue 903 and in a direction parallel to the scanning direction. This state is the second state [T2], which is the state shown in FIG.
この時、軟組織903は、プローブ100の移動に追随して移動する。したがって、プローブ100の送受波面と軟組織903の走査方向の各位置との相対的な位置関係は、プローブ100の移動に応じることなく変化しない。
At this time, the soft tissue 903 moves following the movement of the probe 100. Therefore, the relative positional relationship between the wave transmitting / receiving surface of the probe 100 and each position in the scanning direction of the soft tissue 903 does not change without depending on the movement of the probe 100.
一方、軟骨901は、軟骨下骨911を介して骨902に固着しているので、プローブ100の移動があっても移動しない。したがって、プローブ100の送受波面と軟骨901および軟組織911の走査方向の各位置との相対的な位置関係は、プローブ100の移動に応じて変化する。
On the other hand, since the cartilage 901 is fixed to the bone 902 through the subchondral bone 911, it does not move even if the probe 100 moves. Accordingly, the relative positional relationship between the wave transmitting / receiving surface of the probe 100 and the positions of the cartilage 901 and the soft tissue 911 in the scanning direction changes according to the movement of the probe 100.
第2状態になった後、図3(B)に示すように、プローブ100の各振動子から、軟組織903の表面に直交する方向(送受波面(走査方向)に直交する方向)へ超音波信号を送信する。この各配置位置から送信された超音波信号は、軟組織903や軟骨901、軟骨下骨911の各深度位置で反射し、各振動子によって受信され、データ解析部14でサンプリングされる。この第2状態[T2]で受信したエコーデータSWT21,SWT22,SWT23,SWT24,SWT25のエコーデータ群が第2エコー群SW[T2]となる。
After entering the second state, as shown in FIG. 3B, an ultrasonic signal is transmitted from each transducer of the probe 100 in a direction orthogonal to the surface of the soft tissue 903 (a direction orthogonal to the transmission / reception surface (scanning direction)). Send. The ultrasonic signals transmitted from the respective arrangement positions are reflected at respective depth positions of the soft tissue 903, the cartilage 901, and the subchondral bone 911, received by each transducer, and sampled by the data analysis unit 14. The echo data group of the echo data SWT21, SWT22, SWT23, SWT24, and SWT25 received in the second state [T2] becomes the second echo group SW [T2].
このように、プローブ100の移動前に、複数のエコーデータSWT11,SWT12,SWT13,SWT14,SWT15からなる第1エコー群SW[T1]を取得する。そして、プローブ100の移動後に、複数のエコーデータSWT21,SWT22,SWT23,SWT24,SWT25からなる第2エコー群SW[T2]を取得する。
Thus, before the probe 100 is moved, the first echo group SW [T1] including the plurality of echo data SWT11, SWT12, SWT13, SWT14, and SWT15 is acquired. Then, after the probe 100 is moved, a second echo group SW [T2] including a plurality of echo data SWT21, SWT22, SWT23, SWT24, and SWT25 is acquired.
図5は、第1状態[T1]と第2状態[T2]とでの各エコー波形の例を示す図である。なお、図5では本願発明の特徴を分かりやすく図示するために、プローブ100が移動した距離(移動量)Δxと、各振動子の間隔、すなわち走査位置の間隔が等しいものとしている。また、以下では、この条件において軟組織軟骨境界面の検出の説明を行う。
FIG. 5 is a diagram illustrating examples of echo waveforms in the first state [T1] and the second state [T2]. In FIG. 5, the distance (movement amount) Δx that the probe 100 has moved is assumed to be equal to the interval between the transducers, that is, the interval between the scanning positions, in order to easily illustrate the features of the present invention. In the following, detection of the soft tissue cartilage boundary surface will be described under this condition.
(i)軟骨901および軟骨下骨911 プローブ100が移動しても、軟骨901および軟骨下骨911は移動しない。したがって、プローブ100が距離Δxだけ移動すると、プローブ100の各振動子の位置(各走査位置)と軟骨901および軟骨下骨911の各位置との位置関係が、走査方向に沿って移動量Δxだけずれる。
(I) Cartilage 901 and subchondral bone 911 Even if the probe 100 moves, the cartilage 901 and subchondral bone 911 do not move. Therefore, when the probe 100 moves by the distance Δx, the positional relationship between the position of each transducer of the probe 100 (each scanning position) and each position of the cartilage 901 and the subchondral bone 911 is the movement amount Δx along the scanning direction. Shift.
この場合、図5の第1状態[T1]の各エコー波形および第2状態[T2]の各エコー波形に示すように、第1エコー群SW[T1]の軟骨901および軟骨下骨911の領域のエコーデータSWT11は、第2エコー群SW[T2]のエコーデータSWT21の軟骨901および軟骨下骨911の領域の波形とは一致せず、第2エコー群SW[T2]のエコーデータSWT22の軟骨901および軟骨下骨911の領域の波形と略一致する。
In this case, as shown in each echo waveform in the first state [T1] and each echo waveform in the second state [T2] in FIG. 5, regions of the cartilage 901 and the subchondral bone 911 in the first echo group SW [T1] The echo data SWT11 of the second echo group SW [T2] does not match the waveform of the cartilage 901 and subchondral bone 911 regions of the echo data SWT21 of the second echo group SW [T2], and the cartilage of the echo data SWT22 of the second echo group SW [T2] 901 and the subchondral bone 911 regions substantially match the waveform.
同様に、エコーデータSWT12の軟骨901および軟骨下骨911の領域とエコーデータSWT23の軟骨901および軟骨下骨911の領域とで、波形が略一致する。エコーデータSWT13の軟骨901および軟骨下骨911の領域とエコーデータSWT24の軟骨901および軟骨下骨911の領域とで波形が略一致する。エコーデータSWT14の軟骨901および軟骨下骨911の領域とエコーデータSWT25の軟骨901および軟骨下骨911の領域とで波形が略一致する。
Similarly, the waveforms of the cartilage 901 and the subchondral bone 911 area of the echo data SWT12 and the areas of the cartilage 901 and the subchondral bone 911 of the echo data SWT23 are substantially the same. The waveforms of the cartilage 901 and subchondral bone 911 areas of the echo data SWT13 and the areas of the cartilage 901 and subchondral bone 911 areas of the echo data SWT24 substantially match. The waveforms of the cartilage 901 and the subchondral bone 911 in the echo data SWT14 and the areas of the cartilage 901 and the subchondral bone 911 in the echo data SWT25 are substantially the same.
したがって、軟骨901および軟骨下骨911内では、各走査位置のエコーデータは、第1状態[T1]と第2状態[T2]とで、移動量Δx分、すなわち走査位置が振動子の配置間隔で一つ分ずれた状態で略一致する。すなわち、軟骨901および軟骨下骨911内では、プローブ100を基準とした各エコーデータのサンプル位置は、第1状態[T1]と第2状態[T2]とで、移動量Δx分だけ変化する。このように、軟骨901と軟骨下骨911は同じ移動態様となる。
Accordingly, within the cartilage 901 and the subchondral bone 911, the echo data at each scanning position is the movement amount Δx in the first state [T1] and the second state [T2], that is, the scanning position is the arrangement interval of the transducers. It is almost the same with the state shifted by one. That is, within the cartilage 901 and the subchondral bone 911, the sample position of each echo data based on the probe 100 changes by the movement amount Δx between the first state [T1] and the second state [T2]. Thus, the cartilage 901 and the subchondral bone 911 are in the same movement mode.
(ii)軟組織903 上述のように、プローブ100は軟組織903の表面に当接しており、軟組織903は軟骨901の表面に固定されていない。したがって、プローブ100が移動量Δxだけ移動すると、軟組織903も、プローブ100の移動に追随して、移動量Δxだけ移動する。
(Ii) Soft tissue 903 As described above, the probe 100 is in contact with the surface of the soft tissue 903, and the soft tissue 903 is not fixed to the surface of the cartilage 901. Therefore, when the probe 100 moves by the movement amount Δx, the soft tissue 903 also moves by the movement amount Δx following the movement of the probe 100.
この場合、図5の第1状態[T1]の各エコー波形および第2状態[T2]の各エコー波形に示すように、第1エコー群SW[T1]の軟組織903の領域のエコーデータSWT11は、第2エコー群SW[T2]の軟組織903の領域のエコーデータSWT21の波形と略一致する。
In this case, as shown in each echo waveform of the first state [T1] and each echo waveform of the second state [T2] in FIG. 5, the echo data SWT11 of the soft tissue 903 region of the first echo group SW [T1] is The waveform of the echo data SWT21 in the soft tissue 903 region of the second echo group SW [T2] is substantially the same.
同様に、エコーデータSWT12の軟組織903の領域とエコーデータSWT22の軟組織903の領域とで波形が略一致する。エコーデータSWT13の軟組織903の領域とエコーデータSWT23の軟組織903の領域とで波形が略一致する。エコーデータSWT14の軟組織903の領域とエコーデータSWT24の軟組織903の領域とで波形が略一致する。エコーデータSWT15の軟組織903の領域とエコーデータSWT25の軟組織903の領域とで波形が略一致する。
Similarly, the waveforms of the soft tissue 903 area of the echo data SWT12 and the soft tissue 903 area of the echo data SWT22 are substantially the same. The waveforms of the soft tissue 903 area of the echo data SWT13 and the soft tissue 903 area of the echo data SWT23 are substantially the same. The waveforms of the soft tissue 903 area of the echo data SWT14 and the soft tissue 903 area of the echo data SWT24 are substantially the same. The waveforms of the soft tissue 903 area of the echo data SWT15 and the soft tissue 903 area of the echo data SWT25 are substantially the same.
したがって、軟組織903内では、各走査位置のエコーデータは、第1状態[T1]と第2状態[T2]とで、プローブ100に対する走査方向に沿った位置が略一致する。すなわち、軟組織903内では、プローブ100を基準とした各エコーデータのサンプル位置は、第1状態[T1]と第2状態[T2]とで変化しない。このため、軟組織903のエコーデータの移動態様は、上述の軟骨901や軟骨下骨911のようなプローブ100の移動に応じてエコーデータのサンプル位置が変化する移動態様とは異なる。
Therefore, within the soft tissue 903, the echo data at each scanning position in the first state [T1] and the second state [T2] have substantially the same position along the scanning direction with respect to the probe 100. That is, in the soft tissue 903, the sample position of each echo data with the probe 100 as a reference does not change between the first state [T1] and the second state [T2]. For this reason, the movement mode of the echo data of the soft tissue 903 is different from the movement mode in which the sample position of the echo data changes according to the movement of the probe 100 such as the cartilage 901 and the subchondral bone 911 described above.
このように、軟骨下骨911および軟骨901における特定位置(第1状態[T1]と第2状態[T2]で同じ)で反射したエコーデータのプローブ100を基準としたサンプル位置は、第1状態[T1]と第2状態[T2]とで、移動量Δxだけ走査方向に沿って移動する。
As described above, the sample position with respect to the probe 100 of the echo data reflected at the specific position (the same in the first state [T1] and the second state [T2]) in the subchondral bone 911 and the cartilage 901 is the first state. [T1] and the second state [T2] move along the scanning direction by the movement amount Δx.
一方、軟組織903における特定位置(第1状態[T1]と第2状態[T2]で同じ)で反射したエコーデータのプローブ100を基準としたサンプル位置は、第1状態[T1]と第2状態[T2]とで変化しない。
On the other hand, the sample positions of the echo data reflected at a specific position in the soft tissue 903 (the same in the first state [T1] and the second state [T2]) as a reference are the first state [T1] and the second state. [T2] does not change.
この特性を利用し、本実施形態の軟組織軟骨境界面検出装置では、上述のステップS104に示すように、軟骨下骨911のエコーデータの移動ベクトルを検出する。そして、上述のステップS105に示すように、この移動ベクトルを用いて、第1状態[T1]のエコーデータのサンプル位置と、第2状態[T2]のエコーデータのサンプル位置との位置合わせを行う。言い換えれば、比較対象となる第1状態[T1]のエコーデータのサンプル位置と第2状態[T2]のエコーデータのサンプル位置との組合せを決定する。
Using this characteristic, the soft tissue cartilage boundary surface detection apparatus of the present embodiment detects the movement vector of the echo data of the subchondral bone 911 as shown in step S104 described above. Then, as shown in step S105 described above, this movement vector is used to align the sample position of the echo data in the first state [T1] and the sample position of the echo data in the second state [T2]. . In other words, the combination of the sample position of the echo data in the first state [T1] and the sample position of the echo data in the second state [T2] to be compared is determined.
この際、まず、上述のステップS103に示すように、軟骨下骨911のエコーデータを検出する。図4に示すように、軟骨下骨911のエコーデータは、高いエコーレベル(振幅)となっている。軟骨901は、軟骨表面でエコーレベルが高くなるが、当該軟骨表面と軟骨下骨911との間の領域では、エコーレベルは低い。
At this time, first, echo data of the subchondral bone 911 is detected as shown in step S103 described above. As shown in FIG. 4, the echo data of the subchondral bone 911 has a high echo level (amplitude). The echo level of the cartilage 901 is high on the cartilage surface, but the echo level is low in the region between the cartilage surface and the subchondral bone 911.
したがって、まず、第1エコー群SW[T1]のエコーデータSWT11-SWT15のエコーレベルを深度方向に沿って順次取得していく。そして、所定深度(軟骨の厚さによって適宜設定)に亘り、エコーレベルが軟骨下骨検出用閾値未満であることを検出し、その後に、軟骨下骨検出用閾値以上のエコーレベルを検出する。これにより、このサンプル位置以降を軟骨下骨911のエコーデータとして検出することができる。
Therefore, first, the echo levels of the echo data SWT11-SWT15 of the first echo group SW [T1] are sequentially acquired along the depth direction. Then, it is detected that the echo level is lower than the subchondral bone detection threshold over a predetermined depth (appropriately set according to the thickness of the cartilage), and then an echo level equal to or higher than the subchondral bone detection threshold is detected. Thereby, the part after this sample position can be detected as echo data of the subchondral bone 911.
次に、第2状態[T2]の軟骨下骨911のエコーデータの取得と、第1状態[T1]から第2状態[T2]への軟骨下骨911のエコーデータの移動ベクトルを検出する。図6は、本実施形態に係る移動ベクトルの検出概念を説明するための波形図である。なお、波形自体は、図5の波形図と同じである。
Next, the acquisition of echo data of the subchondral bone 911 in the second state [T2] and the movement vector of the echo data of the subchondral bone 911 from the first state [T1] to the second state [T2] are detected. FIG. 6 is a waveform diagram for explaining the concept of detecting a movement vector according to the present embodiment. The waveform itself is the same as the waveform diagram of FIG.
第1状態[T1]で取得した軟骨下骨911のエコーデータ群に対して、注目領域ZT1CSを設定する。この場合、注目領域ZT1CSは、深度方向(時間方向)の長さで規定されている。具体的には、例えば、図6に示すように、各エコーデータSWT11-SWT15によって決まる走査方向と深度方向とからなる二次元領域に対して、1本のエコーデータの深度方向(時間方向)に沿った所定の範囲を注目領域ZT1CSに設定する。次に、当該注目領域ZT1CS内に含まれるエコーデータを抽出する。これは、言い換えれば、注目領域ZT1CSで切り取られたエコーデータ群の波形に相当する。
A region of interest Z T1CS is set for the echo data group of the subchondral bone 911 acquired in the first state [T1]. In this case, the attention area Z T1CS is defined by the length in the depth direction (time direction). Specifically, for example, as shown in FIG. 6, in the depth direction (time direction) of one echo data with respect to a two-dimensional region having a scanning direction and a depth direction determined by each echo data SWT11-SWT15. A predetermined range along is set as the attention area Z T1CS . Next, the echo data included in the attention area Z T1CS is extracted. In other words, this corresponds to the waveform of the echo data group cut out in the attention area Z T1CS .
次に、第2エコー群SW[T2]のエコーデータSWT21-SWT25に対して、探索領域ZR1を設定する。探索領域ZR1は、プローブ100に対して注目領域ZT1CSの位置を基準として、注目領域ZT1CSよりも広い範囲のエコーデータを含むように決定される。
Next, the echo data SWT21-SWT25 the second echo group SW [T2], sets the search region Z R1. The search area Z R1 is determined so as to include echo data in a wider range than the attention area Z T1CS with reference to the position of the attention area Z T1CS with respect to the probe 100.
具体的には、第2状態[T2]においてプローブ100に対して注目領域ZT1csと同じ位置を、深度方向および走査方向の中心として、深度方向および走査方向の両方に所定範囲拡張した領域によって設定される。例えば、図6に示すように、深度方向において、エコー信号SWT12の深度位置P1csに注目領域ZT1csの中心が設定されている場合、第2状態[T2]のエコー信号SWT22の深度位置P1csに探索領域ZR1の中心を設定する。そして、注目領域の深度方向の長さよりも長い範囲を探索領域ZR1の深度方向の範囲に設定する。なお、深度位置P1csは、探索領域ZR1内であれば、探索領域ZR1の中心でなくてもよい。
Specifically, in the second state [T2], the same position as the region of interest ZT1cs is set with respect to the probe 100 by a region expanded by a predetermined range in both the depth direction and the scanning direction with the center in the depth direction and the scanning direction. Is done. For example, as shown in FIG. 6, in the depth direction, when the center of the attention area Z T1cs is set at the depth position P1cs of the echo signal SWT12, the search is performed at the depth position P1cs of the echo signal SWT22 in the second state [T2]. The center of the region Z R1 is set. Then, a range longer than the depth direction length of the region of interest is set as the depth direction range of the search region ZR1 . Incidentally, the depth position P1cs, if within the search region Z R1, may not be the center of the search area Z R1.
また、走査方向においてエコーデータSWT12に注目領域ZT1CSが設定されている場合、走査方向の中心がエコーデータSWT22となるように、エコーデータSWT21,SWT22,SWT23を含むように、探索領域ZR1の走査方向の範囲を設定する。
When the attention area Z T1CS is set in the echo data SWT12 in the scanning direction, the search area Z R1 is included so as to include the echo data SWT21, SWT22, and SWT23 so that the center in the scanning direction is the echo data SWT22. Set the range in the scanning direction.
次に、第2状態[T2]で取得した軟骨下骨911のエコーデータ群に対して、下骨用比較対象領域ZT2CSを設定する。この際、図6に示すように、下骨用比較対象領域ZT2csは、1本のエコー信号を選択し、深度方向に所定長さの領域とする。下骨用比較対象領域ZT2csの深度方向の長さは、注目領域ZT1csの深度方向の長さと一致するように設定されている。
Next, the lower bone comparison target region Z T2CS is set for the echo data group of the subchondral bone 911 acquired in the second state [T2]. At this time, as shown in FIG. 6, the lower bone comparison target region ZT2cs selects one echo signal and sets it as a region having a predetermined length in the depth direction. The depth direction length of the lower bone comparison target region Z T2cs is set to match the depth direction length of the attention region Z T1cs .
下骨用比較対象領域ZT2CSは、上述のように設定した探索領域ZR1の全域に亘るように設定されている。このように設定された下骨用比較対象領域ZT2CS毎に、エコーデータを取得する。
Comparison regions Z T2CS for the lower bone is set to span the entire search area Z R1 which is set as described above. Echo data is acquired for each lower bone comparison target region ZT2CS set in this way.
次に、注目領域ZT1CSのエコーデータと、下骨用比較対象領域ZT2CSのエコーデータとを相関処理して相関係数を算出する。
Next, a correlation coefficient is calculated by performing a correlation process on the echo data of the attention area Z T1CS and the echo data of the lower bone comparison target area Z T2CS .
注目領域ZT1CSのエコーデータと、下骨用比較対象領域ZT2CSのエコーデータとの相関係数の算出は、下骨用比較対象領域ZT2CSの位置を順次変更させながら、探索領域ZR1の全域に亘って行う。
And echo data of the region of interest Z T1CS, calculation of the correlation coefficient between the echo data of the comparison regions Z T2CS for the lower bone, while sequentially changing the position of the comparison area Z T2CS for the lower bone, the search area Z R1 Perform over the entire area.
このような一つの注目領域ZT1CSに対する相関係数の算出を、探索領域ZR1の全域に対して実行する。
The calculation of the correlation coefficients for such a region of interest Z T1CS, be performed on the entire search area Z R1.
次に、注目領域ZT1CS毎に相関係数が最大となる下骨用比較対象領域ZT2CSを検出する。これが軟骨下骨911領域における最も類似する領域に相当し、第2状態[T2]での軟骨下骨911のエコーデータとなる。このようにエコー信号の類似度から第2状態[T2]での軟骨下骨911のエコーデータを検出する。
Next, a correlation coefficient for each region of interest Z T1CS detects a comparison regions Z T2CS for the lower bone becomes maximum. This corresponds to the most similar region in the subchondral bone 911 region, and becomes echo data of the subchondral bone 911 in the second state [T2]. In this manner, the echo data of the subchondral bone 911 in the second state [T2] is detected from the similarity of the echo signals.
次に、第1状態[T1]から第2状態[T2]への軟骨下骨911のエコーデータの移動ベクトル(移動方向、移動量)を検出する。
Next, a movement vector (movement direction, movement amount) of echo data of the subchondral bone 911 from the first state [T1] to the second state [T2] is detected.
ここで、移動ベクトルとは、次のように定義することができる。図7は本実施形態に係る移動ベクトルの定義を示す図である。なお、図7では注目領域と下骨用比較対象領域を用いた場合を示す。移動ベクトルvmは、互いに最も類似すると判断された注目領域の代表点と下骨用比較対象領域の代表点の位置から定義される。移動ベクトルvmは、注目領域の代表点を始点として、下骨用比較対象領域の代表点を終点とするベクトルであり、移動方向と移動量とによって定義される。
Here, the movement vector can be defined as follows. FIG. 7 is a diagram showing the definition of the movement vector according to the present embodiment. FIG. 7 shows a case where the attention area and the lower bone comparison target area are used. Moving vector v m is defined from the position of the representative point of the representative point and the lower bone for comparison regions of the region of interest is determined to be most similar to each other. Moving vector v m as a starting point a representative point of the region of interest, a vector and terminating the representative point of the comparison regions for the lower bone, is defined by the moving direction and the moving amount.
具体的に、例えば、図7の例では、注目領域の代表点は、エコー信号SWT11上すなわち走査方向位置P1で、所定の深度位置に存在する。また、下骨用比較対象領域の代表点は、エコー信号SWT22上すなわち走査方向位置P2で、所定の深度位置に存在する。注目領域の代表点の深度位置と下骨用比較対象領域の代表点の深度位置は、同じである。
Specifically, for example, in the example of FIG. 7, the representative point of the region of interest exists at a predetermined depth position on the echo signal SWT11, that is, in the scanning direction position P1. In addition, the representative point of the lower bone comparison target region exists on the echo signal SWT22, that is, in the scanning direction position P2, at a predetermined depth position. The depth position of the representative point of the attention area is the same as the depth position of the representative point of the lower bone comparison target area.
この場合、移動ベクトルvmは、走査方向を移動方向とし、走査位置P1,P2の間隔Δxを移動量とするベクトルとなる。
In this case, the movement vector v m is a vector in which the scanning direction is the movement direction and the distance Δx between the scanning positions P1 and P2 is the movement amount.
このような移動ベクトルの算出は、軟骨下骨911の全てのエコーデータで行ってもよく、代表する1つもしくは複数のエコーデータで行ってもよい。全てのエコーデータもしくは複数のエコーデータで行う場合には、それぞれに算出された移動ベクトルの平均を、軟骨下骨911の移動ベクトルとするとよい。
Such calculation of the movement vector may be performed on all echo data of the subchondral bone 911 or may be performed on one or more representative echo data. When performing with all echo data or a plurality of echo data, the average of the movement vectors calculated for each may be used as the movement vector of the subchondral bone 911.
このように移動ベクトルが算出された場合、軟骨901および軟組織903の各エコーデータの移動ベクトルは図8のような分布となる。図8は、本実施形態に係る移動ベクトルの分布状態を示す図である。図8に示すように、軟骨下骨911領域のエコーデータの移動ベクトルvmがΔxであると、軟骨901領域のエコーデータの移動ベクトルvmもΔxとなる。しかしながら、軟組織903のエコーデータの移動ベクトルvmは0となり、軟骨下骨911および軟骨901の移動ベクトルとは異なる。
When the movement vector is calculated in this way, the movement vector of each echo data of the cartilage 901 and the soft tissue 903 has a distribution as shown in FIG. FIG. 8 is a diagram showing a distribution state of movement vectors according to the present embodiment. As shown in FIG. 8, when the movement vector vm of the echo data in the subchondral bone 911 region is Δx, the movement vector vm of the echo data in the cartilage 901 region is also Δx. However, the movement vector vm of the echo data of the soft tissue 903 is 0, which is different from the movement vectors of the subchondral bone 911 and the cartilage 901.
この特性を利用し、次に示す方法で、各エコーデータが軟骨901に属するか、軟組織903に属するかを検出する。図9はエコーデータが軟骨901に属するか軟組織903に属するかを検出する方法(第1の方法)を説明するための波形図である。
Using this characteristic, whether each echo data belongs to cartilage 901 or soft tissue 903 is detected by the following method. FIG. 9 is a waveform diagram for explaining a method (first method) for detecting whether echo data belongs to cartilage 901 or soft tissue 903.
第1状態[T1]で取得したエコーデータ群に対して、第1比較対象領域ZT1nを設定する(nは深度方向に沿ったサンプル位置数から決定される整数である)。この場合、第1比較対象領域ZT1nは、深度方向(時間方向)の長さで規定されている。具体的な例としては、例えば、図9に示すように、各エコーデータSWT11-SWT15によって決まる走査方向と深度方向とからなる二次元領域に対して、1本のエコーデータの深度方向(時間方向)に沿った所定の範囲を第1比較対象領域ZT11に設定する。次に、当該第1比較対象領域ZT11内に含まれるエコーデータを抽出する。これは、言い換えれば、第1比較対象領域ZT11で切り取られたエコーデータ群の波形に相当する。なお、第1比較対象領域ZT11は、軟骨下骨911の領域を除いて設定すればよく、軟骨901における軟骨下骨911に近いエコーレベルの低い領域も除いて設定してもよい。
A first comparison target area ZT1n is set for the echo data group acquired in the first state [T1] (n is an integer determined from the number of sample positions along the depth direction). In this case, the first comparison target region ZT1n is defined by the length in the depth direction (time direction). As a specific example, for example, as shown in FIG. 9, the depth direction (time direction) of one echo data with respect to a two-dimensional region having a scanning direction and a depth direction determined by each echo data SWT11-SWT15. ) Is set to the first comparison target area ZT11 . Next, the echo data included in the first comparison target area ZT11 is extracted. In other words, this corresponds to the waveform of the echo data group cut out in the first comparison target area ZT11 . Note that the first comparison target region ZT11 may be set by excluding the region of the subchondral bone 911, and may be set by excluding the region of the cartilage 901 that is close to the subchondral bone 911 and has a low echo level.
次に、第2状態[T2]で取得したエコーデータ群に対して、第2比較対象領域ZT2nを設定する(nは深度方向に沿ったサンプル位置数から決定される整数である)。この場合、第2比較対象領域ZT2nは、第1比較対象領域ZT1nを移動ベクトルで移動させた位置に設定されている。
Next, a second comparison target region ZT2n is set for the echo data group acquired in the second state [T2] (n is an integer determined from the number of sample positions along the depth direction). In this case, the second comparison target region Z T2n is set at a position where the first comparison target region Z T1n is moved by the movement vector.
より具体的には、第1状態[T1]で第1比較対象領域ZT1nのエコーデータを得た振動子と同じ振動子によって、第2状態[T2]で第1比較対象領域ZT1nと同じ深度領域を検出する。そして、この領域を移動ベクトルで移動させて得られる第2状態[T2]での深度領域を、第2比較対象領域ZT2nに設定する。すなわち、比較対象とする第1状態[T1]のエコーデータのサンプル位置と第2状態[T2]のエコーデータのサンプル位置を、移動ベクトルによって位置合わせする。
More specifically, it is the same as the first comparison target region Z T1n in the second state [T2] by the same transducer that has obtained the echo data of the first comparison target region Z T1n in the first state [T1]. Detect depth region. Then, the depth region in the second state [T2] obtained by moving this region with the movement vector is set as the second comparison target region ZT2n . That is, the sample position of the echo data in the first state [T1] to be compared and the sample position of the echo data in the second state [T2] are aligned by the movement vector.
具体的な例としては、上述のような走査方向にのみ移動する移動ベクトルΔxが得られた場合、図9に示すように、第1状態[T1]のエコーデータSWT12の所定深度位置P11に第1比較対象領域ZT11が設定されると、同じ振動子によって第2状態[T2]で得られるエコーデータSWT22から移動ベクトルΔxだけ移動したエコーデータSWT23の所定深度位置P21に第2比較対象領域ZT21を設定する。
As a specific example, when the movement vector Δx that moves only in the scanning direction as described above is obtained, as shown in FIG. 9, the first state [T1] echo data SWT12 is set to a predetermined depth position P11. When one comparison region Z T11 is set at a predetermined depth position P21 of the echo data SWT23 moved by the movement vector Δx from the echo data SWT22 obtained in the second state [T2] of the same vibrator second comparison regions Z T21 is set.
同様に、図9に示すように、第1状態[T1]のエコーデータSWT12の所定深度位置P12に第1比較対象領域ZT12が設定されると、同じ振動子によって第2状態[T2]で得られるエコーデータSWT22から移動ベクトルΔxだけ移動したエコーデータSWT23の所定深度位置P22に第2比較対象領域ZT22を設定する。
Similarly, as shown in FIG. 9, when the first comparison target region Z T12 is set at the predetermined depth position P12 of the echo data SWT12 in the first state [T1], the same transducer causes the second state [T2]. the predetermined depth position P22 of the echo data SWT23 from echo data SWT22 obtained moved by movement vector Δx setting the second comparison regions Z T22.
次に、第1比較対象領域ZT1nのエコーデータと第2比較対象領域ZT2nのエコーデータとの相関係数を算出する。
Next, a correlation coefficient between the echo data of the first comparison target region Z T1n and the echo data of the second comparison target region Z T2n is calculated.
ここで、上述のように、軟骨901は、軟骨下骨911と同じ移動ベクトルで移動しており、移動態様は同じとなる。したがって、移動ベクトルによって位置合わせされた第1比較対象領域ZT1nのエコーデータと第2比較対象領域ZT2nのエコーデータとの相関係数は略1になる。すなわち、相関係数は高くなる。
Here, as described above, the cartilage 901 moves with the same movement vector as the subchondral bone 911, and the movement mode is the same. Therefore, the correlation coefficient between the echo data of the first comparison target region Z T1n and the echo data of the second comparison target region Z T2n aligned by the movement vector is approximately 1. That is, the correlation coefficient becomes high.
一方、軟組織903は、軟骨901および軟骨下骨911と同じように移動しないので、移動態様は異なる。したがって、移動ベクトルによって位置合わせされた第1比較対象領域ZT1nのエコーデータと第2比較対象領域ZT2nのエコーデータとの相関係数は0に近づく。すなわち、相関係数は低くなる。
On the other hand, since the soft tissue 903 does not move in the same manner as the cartilage 901 and the subchondral bone 911, the movement mode is different. Therefore, the correlation coefficient between the echo data of the first comparison target region Z T1n and the echo data of the second comparison target region Z T2n aligned by the movement vector approaches zero. That is, the correlation coefficient is low.
例えば、図9に示すように、軟骨901内に設定された第1比較対象領域ZT12のエコーデータと第2比較対象領域ZT22のエコーデータは同じ波形であり、相関係数は高くなる。一方、軟組織903内に設定された第1比較対象領域ZT11のエコーデータと第2比較対象領域ZT21のエコーデータは異なる波形であり、相関係数は低くなる。
For example, as shown in FIG. 9, the echo data of the first comparison target region ZT12 and the echo data of the second comparison target region ZT22 set in the cartilage 901 have the same waveform, and the correlation coefficient is high. On the other hand, the echo data of the first comparison target region Z T11 and the echo data of the second comparison target region Z T21 set in the soft tissue 903 have different waveforms, and the correlation coefficient is low.
このように、相関係数が高い比較対象領域のエコーデータは、軟骨901内のエコーデータであると判断でき、相関係数が低い比較対象領域のエコーデータは、軟組織903内のエコーデータであると判断できる。
Thus, it can be determined that the echo data of the comparison target region having a high correlation coefficient is the echo data in the cartilage 901, and the echo data of the comparison target region having a low correlation coefficient is the echo data in the soft tissue 903. It can be judged.
したがって、このような第1比較対象領域ZT11のエコーデータと第2比較対象領域ZT21の相関係数を、軟骨下骨911の領域以外の各エコーデータに対して算出することで、各エコーデータが軟組織903内であるか軟骨901内であるかを検出することができる。そして、軟組織903内と判断されたエコーデータ群と軟骨901内と判断されたエコーデータ群との境界を検出することで、軟組織903と軟骨901の境界面を検出することができる。
Accordingly, by calculating the correlation coefficient between the echo data of the first comparison target region Z T11 and the second comparison target region Z T21 for each echo data other than the region of the subchondral bone 911, each echo is calculated. Whether the data is in soft tissue 903 or cartilage 901 can be detected. The boundary surface between the soft tissue 903 and the cartilage 901 can be detected by detecting the boundary between the echo data group determined to be within the soft tissue 903 and the echo data group determined to be within the cartilage 901.
以上のように、本実施形態の構成および処理を用いることで、非侵襲で正確に軟組織と軟骨との境界面を検出することができる。なお、非侵襲な方法としては、全てのエコーデータを注目領域に設定し、それぞれの注目領域に相関係数の高い比較対象領域を探索して検出し、注目領域と比較対象領域との移動態様から軟組織と軟骨の境界面を検出することもできる。しかしながら、本実施形態の構成および処理を用いることで、全ての領域に対する探索処理を行う必要が無いので、軟組織と軟骨の境界面を、より高速に検出することができる。
As described above, by using the configuration and processing of this embodiment, it is possible to accurately detect the boundary surface between soft tissue and cartilage in a non-invasive manner. As a non-invasive method, all echo data is set in a region of interest, a comparison target region having a high correlation coefficient is searched and detected in each region of interest, and the movement mode between the region of interest and the comparison target region It is also possible to detect the interface between soft tissue and cartilage. However, by using the configuration and processing of the present embodiment, it is not necessary to perform search processing for all regions, so that the boundary surface between soft tissue and cartilage can be detected at higher speed.
なお、上述の説明では、第2状態[T2]で取得したエコーデータのサンプル位置を移動ベクトルで移動させて、比較対象領域を設定する例を示したが、第1状態[T1]で取得したエコーデータのサンプル位置を移動ベクトルに基づいて移動させて、比較対象領域を設定してもよい。
In the above description, the example in which the sample area of the echo data acquired in the second state [T2] is moved by the movement vector to set the comparison target region is shown. However, the sample is acquired in the first state [T1]. The comparison target area may be set by moving the sample position of the echo data based on the movement vector.
図10はエコーデータが軟骨901に属するか軟組織903に属するかを検出する方法(第2の方法)を説明するための波形図である。第2の方法では、第2状態[T2]で取得したエコーデータを基準とする。
FIG. 10 is a waveform diagram for explaining a method (second method) for detecting whether the echo data belongs to the cartilage 901 or the soft tissue 903. In the second method, the echo data acquired in the second state [T2] is used as a reference.
第2状態[T2]で取得したエコーデータ群に対して、第2比較対象領域ZT2nを設定する(nは深度方向に沿ったサンプル位置数から決定される整数である)。具体的な例としては、例えば、図10に示すように、各エコーデータSWT21-SWT25によって決まる走査方向と深度方向とからなる二次元領域に対して、1本のエコーデータの深度方向(時間方向)に沿った所定の範囲を第2比較対象領域ZT21に設定する。次に、当該第2比較対象領域ZT21内に含まれるエコーデータを抽出する。これは、言い換えれば、第2比較対象領域ZT21で切り取られたエコーデータ群の波形に相当する。
A second comparison target region ZT2n is set for the echo data group acquired in the second state [T2] (n is an integer determined from the number of sample positions along the depth direction). As a specific example, for example, as shown in FIG. 10, the depth direction (time direction) of one echo data with respect to a two-dimensional region having a scanning direction and a depth direction determined by each echo data SWT21-SWT25. ) Is set in the second comparison target area ZT21 . Next, echo data included in the second comparison target region ZT21 is extracted. In other words, this corresponds to the waveform of the echo data group cut out in the second comparison target region ZT21 .
次に、第1状態[T1]で取得したエコーデータ群に対して、第1比較対象領域ZT1nを設定する(nは深度方向に沿ったサンプル位置数から決定される整数である)。この場合、第1比較対象領域ZT1nは、第2比較対象領域ZT2nを移動ベクトルに基づいて、移動ベクトルと反対方向で且つ移動ベクトルの大きさに応じた移動させた位置に設定されている。
Next, the first comparison target region Z T1n is set for the echo data group acquired in the first state [T1] (n is an integer determined from the number of sample positions along the depth direction). In this case, the first comparison target area Z T1n is set to a position where the second comparison target area Z T2n is moved in the direction opposite to the movement vector and according to the magnitude of the movement vector, based on the movement vector. .
より具体的には、第2状態[T2]で第1比較対象領域ZT2nのエコーデータを得た振動子と同じ振動子によって、第1状態[T1]で第2比較対象領域ZT2nと同じ深度領域を検出する。そして、この領域を移動ベクトルに基づいて移動させて得られる第1状態[T1]での深度領域を、第1比較対象領域ZT1nに設定する。すなわち、比較対象とする第2状態[T2]のエコーデータのサンプル位置に対して、第1状態[T1]のエコーデータのサンプル位置を、移動ベクトルに基づいて位置合わせする。
More specifically, it is the same as the second comparison target region Z T2n in the first state [T1] by the same transducer that has obtained the echo data of the first comparison target region Z T2n in the second state [T2]. Detect depth region. Then, the depth region in the first state [T1] obtained by moving this region based on the movement vector is set as the first comparison target region ZT1n . That is, the sample position of the echo data in the first state [T1] is aligned with the sample position of the echo data in the second state [T2] to be compared based on the movement vector.
具体的な例としては、上述のような走査方向にのみ移動する移動ベクトルΔxが得られた場合、図10に示すように、第2状態[T2]のエコーデータSWT22の所定深度位置P21に第2比較対象領域ZT21が設定されると、同じ振動子によって第1状態[T1]で得られるエコーデータSWT12から移動ベクトルΔxだけ反対方向に移動したエコーデータSWT11の所定深度位置P11に第1比較対象領域ZT11を設定する。
As a specific example, when the movement vector Δx that moves only in the scanning direction as described above is obtained, as shown in FIG. 10, the second state [T2] echo data SWT22 in the predetermined depth position P21 When 2 comparison regions Z T21 is set, the first compared to a predetermined depth position P11 of the echo data SWT11 moved only in the opposite direction movement vector Δx from the echo data SWT12 which the same oscillator obtained in the first state [T1] The target area ZT11 is set.
同様に、図10に示すように、第2状態[T2]のエコーデータSWT22の所定深度位置P22に第2比較対象領域ZT22が設定されると、同じ振動子によって第1状態[T1]で得られるエコーデータSWT12から移動ベクトルΔxだけ反対方向に移動したエコーデータSWT11の所定深度位置P12に第1比較対象領域ZT12を設定する。
Similarly, as shown in FIG. 10, when the second comparison regions Z T22 is set to a predetermined depth position P22 of the echo data SWT22 the second state [T2], in the first state [T1] by the same oscillator from the echo data SWT12 obtained by the movement vector Δx sets a first comparison area Z T12 at a predetermined depth position P12 of the echo data SWT11 which moves in the opposite direction.
次に、第2比較対象領域ZT2nのエコーデータと第1比較対象領域ZT1nのエコーデータとの相関係数を算出する。
Next, a correlation coefficient between the echo data of the second comparison target region Z T2n and the echo data of the first comparison target region Z T1n is calculated.
このような処理を行っても、非侵襲で正確に軟組織と軟骨との境界面を検出することができる。
Even if such processing is performed, the boundary surface between soft tissue and cartilage can be accurately detected non-invasively.
また、上述の説明では、第1比較対象領域ZT1nのエコーデータと第2比較対象領域T1nのエコーデータとの相関係数から軟組織および軟骨を判別する例を示した。しかしながら、第1状態[T1]の各スイープのエコー信号の波形と、第2状態[T2]の各スイープのエコー信号の波形との類似度を、別の方法で検出し、この類似度から軟組織および軟骨を判別してもよい。
In the above description, an example is shown in which soft tissue and cartilage are discriminated from the correlation coefficient between the echo data of the first comparison target region Z T1n and the echo data of the second comparison target region T1n . However, the similarity between the waveform of the echo signal of each sweep in the first state [T1] and the waveform of the echo signal of each sweep in the second state [T2] is detected by another method. And cartilage may be distinguished.
具体的な一例としては、ノルムを用いる方法がある。ノルムNormは、次に示す式により定義することができる。
A specific example is a method using a norm. The norm Norm can be defined by the following equation.
ここで、Ddzt1(i)は、第1比較対象領域ZT1nの深度方向位置iの点のエコーデータ値である。Ddzt2(i)は、第2比較対象領域ZT2nの深度方向位置iの点のエコーデータ値である。kは、第1比較対象領域ZT1nおよび第2比較対象領域ZT2nの分解能に相当し、第1比較対象領域ZT1nおよび第2比較対象領域ZT2nに含まれるエコーデータの総数を示す。mは適宜設定した定数である。
Here, Ddzt1 (i) is an echo data value of a point at the position i in the depth direction of the first comparison target region ZT1n . Ddzt2 (i) is the echo data value at the point in the depth direction position i of the second comparison regions Z T 2 n. k corresponds to the resolution of the first comparison area Z T1n and second comparison regions Z T 2 n, the total number of echo data contained in the first comparison region Z T1n and second comparison regions Z T 2 n. m is an appropriately set constant.
このように、ノルムNormは、第1比較対象領域ZT1nと第2比較対象領域ZT2nの同一位置のエコーデータの差分の絶対値をn乗し、このn乗値を領域全体で加算して、1/n乗した値である。したがって、第1比較対象領域ZT1nと第2比較対象領域ZT2nとが類似度が高いほどノルムNormは小さくなり、類似度が低いほどノルムNormは大きくなる。
In this way, the norm Norm raises the absolute value of the difference between the echo data at the same position in the first comparison target region Z T1n and the second comparison target region Z T2n to the nth power, and adds the nth power value over the entire region. , 1 / nth power. Accordingly, a first comparison area Z T1n and the second comparison region Z T 2 n norm Norm higher similarity decreases, the more the norm Norm similarity is low is increased.
これにより、ノルムが小さい第1比較対象領域ZT1nと第2比較対象領域ZT2nは、相関係数が高い場合に相当し、軟骨901内であると判断できる。そして、ノルムが大きい第1比較対象領域ZT1nと第2比較対象領域ZT2nは、相関係数が低い場合に相当し、軟組織903内であると判断できる。
Accordingly, the first comparison target region Z T1n and the second comparison target region Z T2n having a small norm correspond to a case where the correlation coefficient is high, and can be determined to be within the cartilage 901. The first comparison target region Z T1n and the second comparison target region Z T2n having a large norm correspond to the case where the correlation coefficient is low, and can be determined to be in the soft tissue 903.
このようなノルムを用いる方法は、軟骨下骨911の移動ベクトルを検出する場合にも利用できる。具体的には、注目領域ZT1CSに対して最もノルムNormの小さい下骨用比較対象領域ZT2CSを検出する。そして、ノルムNormが最小となる組合せの注目領域ZT1CSの代表位置を起点として、下骨用比較対象領域ZT2CSの代表位置を終点とするベクトルを算出することで、移動ベクトルを検出することができる。
Such a method using the norm can also be used when detecting the movement vector of the subchondral bone 911. Specifically, to detect the most norm Norm small for the lower bone comparison regions Z T2CS for the target region Z T1CS. The movement vector can be detected by calculating a vector starting from the representative position of the attention area Z T1CS of the combination having the minimum norm Norm and starting from the representative position of the lower bone comparison target area Z T2CS. it can.
なお、上述の説明では、軟骨表面検出のための各処理を複数の機能ブロックで実現する例を示した。しかしながら、上述の軟骨表面検出処理をプログラム化して記憶しておき、コンピュータで当該プログラムを読み出して実行するようにしてもよい。
In the above description, an example in which each process for cartilage surface detection is realized by a plurality of functional blocks is shown. However, the above-described cartilage surface detection process may be programmed and stored, and the program may be read and executed by a computer.
また、上述の説明では、被検知体である膝の軟組織903の表面にプローブ100を当接し、当該プローブ100を走査方向に移動させる例を示した。しかしながら、プローブ100を固定し、膝を治具等で屈曲させることで、プローブ100と軟組織903、軟骨901および軟骨下骨911との相対位置関係を変化させてもよい。
In the above description, the example in which the probe 100 is brought into contact with the surface of the soft tissue 903 of the knee, which is the detection target, and the probe 100 is moved in the scanning direction is shown. However, the relative positional relationship between the probe 100 and the soft tissue 903, the cartilage 901, and the subchondral bone 911 may be changed by fixing the probe 100 and bending the knee with a jig or the like.
また、上述の説明のプローブは、振動子を走査方向の一方向のみに沿って配列設置したものである。しかしながら、走査方向と、走査方向および深度方向に直交する方向との二次元領域において所定間隔をおいて振動子を配列するようにしてもよい。
In the probe described above, transducers are arranged and arranged along only one direction of the scanning direction. However, the transducers may be arranged at a predetermined interval in a two-dimensional region of the scanning direction and the direction orthogonal to the scanning direction and the depth direction.
また、振動子を1つにして、当該振動子を走査方向に移動させる構成であってもよい。図11は、振動子を移動させるメカニカルスキャンによる検出構成を示す図である。
Alternatively, a configuration in which one transducer is used and the transducer is moved in the scanning direction may be used. FIG. 11 is a diagram showing a detection configuration by mechanical scanning for moving the transducer.
メカニカルスキャン型のプローブ100Aは、振動子を有する送受波器を備える。送受波器は、走査軸に沿って移動可能に設置されている。送受波器は、走査軸に沿って移動する。送受波器の振動子は、走査方向に直交する方向に超音波信号を送信する。この送受波器を、走査方向に移動させながら、複数の走査位置で停止して超音波信号を送信し、そのエコー信号を受信することで、振動子を複数有するプローブ100と同じエコー信号を得ることができる。
The mechanical scan type probe 100A includes a transducer having a vibrator. The transducer is installed so as to be movable along the scanning axis. The transducer moves along the scan axis. The transducer of the transducer transmits an ultrasonic signal in a direction orthogonal to the scanning direction. While moving this transducer in the scanning direction, it stops at a plurality of scanning positions, transmits an ultrasonic signal, and receives the echo signal, thereby obtaining the same echo signal as the probe 100 having a plurality of transducers. be able to.
なお、上述の説明では、プローブ100に対する軟骨901および軟骨下骨911の各サンプル位置が走査方向にのみ移動する場合を示したが、走査方向と深度方向の両方に移動する場合にも、上述のような構成及び処理を適用することができる。
In the above description, the case where each sample position of the cartilage 901 and the subchondral bone 911 with respect to the probe 100 is moved only in the scanning direction is described. Such a configuration and processing can be applied.
また、第1状態[T1]での軟骨下骨の検出方法は、上述のように、深度の浅い側から順にエコーレベルを閾値と比較する方法に限らず、深度の深い側から順にエコーレベルを閾値と比較する方法を用いてもよい。具体的には、軟骨下骨よりも内側の骨内部はエコーの減衰量が大きいため、エコーレベルは略0となる。したがって、閾値を略0よりも大きな所定値に設定する。そして、深度の深い側、すなわち、骨内部側からエコーレベルを閾値と比較し、エコーレベルが当該閾値以上になった位置のエコーデータを軟骨下骨のエコーデータとして取得する。
In addition, as described above, the subchondral bone detection method in the first state [T1] is not limited to the method of comparing the echo level with the threshold value in order from the depth side, but the echo level is set in order from the depth side. A method of comparing with a threshold value may be used. Specifically, since the echo attenuation amount is large inside the bone inside the subchondral bone, the echo level is substantially zero. Therefore, the threshold value is set to a predetermined value larger than approximately zero. Then, the echo level is compared with a threshold value from the deep side, that is, the inside of the bone, and echo data at a position where the echo level is equal to or higher than the threshold value is acquired as echo data of the subchondral bone.
また、上述の説明では、第2状態[T2]での軟骨下骨の検出方法として、第1状態[T1]のエコー信号との類似度を用いる例を示したが、第2状態[T2]の軟骨下骨エコー信号も、第1状態[T1]の軟骨下骨エコー信号の検出と同様に、閾値との比較で行ってもよい。
In the above description, as an example of the subchondral bone detection method in the second state [T2], the similarity with the echo signal in the first state [T1] is used. However, the second state [T2] Similarly to the detection of the subchondral bone echo signal in the first state [T1], the subchondral bone echo signal may be compared with a threshold value.
10:軟組織軟骨境界面検出装置、11:操作部、12:送信制御部、13:エコー信号受信部、14:データ解析部、100,100A:プローブ、141:AD変換部、142:記憶部、143:判定部、901:軟骨、902:骨、903:軟組織、911:軟骨下骨
10: soft tissue cartilage boundary surface detection device, 11: operation unit, 12: transmission control unit, 13: echo signal reception unit, 14: data analysis unit, 100, 100A: probe, 141: AD conversion unit, 142: storage unit, 143: determination unit, 901: cartilage, 902: bone, 903: soft tissue, 911: subchondral bone
Claims (17)
- 軟組織と軟骨の境界面を検出する軟組織軟骨境界面検出方法であって、
前記第1の状態で超音波信号を前記被検知体内に送信して第1のエコー信号を得る第1エコー信号送受信工程と、
前記第2の状態で超音波信号を前記被検知体内に送信して第2のエコー信号を得る第2エコー信号送受信工程と、
前記第1のエコー信号を用いて第1の状態の軟骨下骨エコー信号を検出し、前記第2のエコー信号を用いて第2の状態の軟骨下骨エコー信号を検出する軟骨下骨検出工程と、
前記第1の状態の軟骨下骨エコー信号と前記第2の状態の軟骨下骨エコー信号とから、前記第1の状態から前記第2の状態への軟骨下骨の移動ベクトルを検出する、移動ベクトル検出工程と、
前記移動ベクトルに基づいて前記第1の状態と前記第2の状態のエコー信号のサンプル位置を補正して、前記軟組織と前記軟骨の境界面を検出する、境界面検出工程と、
を有することを特徴とする軟組織軟骨境界面検出方法。 A soft tissue cartilage interface detection method for detecting a soft tissue / cartilage interface,
A first echo signal transmitting / receiving step of transmitting an ultrasonic signal in the detected body to obtain a first echo signal in the first state;
A second echo signal transmitting / receiving step of transmitting an ultrasonic signal into the body to be detected in the second state to obtain a second echo signal;
A subchondral bone detection step of detecting a subchondral bone echo signal in a first state using the first echo signal and detecting a subchondral bone echo signal in a second state using the second echo signal. When,
A movement for detecting a movement vector of the subchondral bone from the first state to the second state from the subchondral bone echo signal in the first state and the subchondral bone echo signal in the second state A vector detection process;
A boundary surface detection step of correcting a sample position of the echo signal of the first state and the second state based on the movement vector and detecting a boundary surface of the soft tissue and the cartilage;
A method of detecting a soft tissue cartilage boundary surface. - 請求項1に記載の軟組織軟骨境界面検出方法であって、
前記境界面検出工程は、
前記移動ベクトルにより、前記第1のエコー信号の各サンプル位置と、前記第2のエコー信号の各サンプル位置との位置合わせを行い、
位置合わせ後の同一サンプル位置のエコー信号に基づいて、前記軟組織と前記軟骨の境界面を検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 1,
The boundary surface detection step includes
With the movement vector, each sample position of the first echo signal is aligned with each sample position of the second echo signal,
Detecting an interface between the soft tissue and the cartilage based on an echo signal at the same sample position after alignment;
Soft tissue cartilage interface detection method. - 請求項2に記載の軟組織軟骨境界面検出方法であって、
前記境界面検出工程は、
前記位置合わせ後における各サンプル位置での前記第1のエコー信号と前記第2のエコー信号の類似度を検出し、前記類似度から前記境界面を検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 2,
The boundary surface detection step includes
Detecting the similarity between the first echo signal and the second echo signal at each sample position after the alignment, and detecting the boundary surface from the similarity;
Soft tissue cartilage interface detection method. - 請求項3に記載の軟組織軟骨境界面検出方法であって、
前記境界面検出工程は、
前記類似度として、前記サンプル位置を含む比較対象領域の前記第1のエコー信号と前記第2のエコー信号の相関係数を算出し、該相関係数に基づいて前記境界面を検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 3,
The boundary surface detection step includes
Calculating the correlation coefficient between the first echo signal and the second echo signal of the comparison target region including the sample position as the similarity, and detecting the boundary surface based on the correlation coefficient;
Soft tissue cartilage interface detection method. - 請求項3に記載の軟組織軟骨境界面検出方法であって、
前記境界面検出工程は、
前記類似度として、前記サンプル位置を含む比較対象領域の前記第1のエコー信号と前記第2のエコー信号からノルムを算出し、当該ノルムに基づいて前記境界面を検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 3,
The boundary surface detection step includes
As the similarity, a norm is calculated from the first echo signal and the second echo signal of the comparison target region including the sample position, and the boundary surface is detected based on the norm.
Soft tissue cartilage interface detection method. - 請求項1乃至請求項5のいずれかに記載の軟組織軟骨境界面検出方法であって、
前記移動ベクトル検出工程は、
前記第1のエコー信号を用いて第1の軟骨下骨エコー信号を検出し、前記第2のエコー信号を用いて第2の軟骨下骨エコー信号を検出し、
前記第1の軟骨下骨エコー信号と前記第2の軟骨下骨エコー信号とから、前記第1の状態から前記第2の状態への軟骨下骨の移動ベクトルを検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to any one of claims 1 to 5,
The movement vector detection step includes
Detecting a first subchondral bone echo signal using the first echo signal, detecting a second subchondral bone echo signal using the second echo signal;
Detecting a movement vector of the subchondral bone from the first state to the second state from the first subchondral bone echo signal and the second subchondral bone echo signal;
Soft tissue cartilage interface detection method. - 請求項6に記載の軟組織軟骨境界面検出方法であって、
前記移動ベクトル検出工程は、
前記第1の軟骨下骨エコー信号に対して注目領域を設定し、
前記第2の軟骨下骨エコー信号に対して下骨用比較対象領域を設定し、
前記注目領域に対して類似度が高い前記下骨用比較対象領域を類似領域として検出し、前記注目領域と前記類似領域との位置関係から前記移動ベクトルを検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 6,
The movement vector detection step includes
Setting a region of interest for the first subchondral bone echo signal;
A lower bone comparison target region is set for the second subchondral bone echo signal,
Detecting the lower bone comparison target region having a high similarity to the attention region as a similar region, and detecting the movement vector from a positional relationship between the attention region and the similar region;
Soft tissue cartilage interface detection method. - 請求項7に記載の軟組織軟骨境界面検出方法であって、
前記移動ベクトル検出工程は、
前記第2の軟骨下骨エコー信号に対して、前記注目領域よりも広い下骨用探索領域を設定し、該下骨用探索領域内で前記下骨用比較対象領域を設定する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 7,
The movement vector detection step includes
For the second subchondral bone echo signal, set a lower bone search area larger than the region of interest, and set the lower bone comparison target area in the lower bone search area,
Soft tissue cartilage interface detection method. - 請求項7または請求項8に記載の軟組織軟骨境界面検出方法であって、
前記移動ベクトル検出工程は、
前記類似度として、前記第1の軟骨下骨エコー信号と前記第2の軟骨下骨エコー信号の相関係数を算出し、該相関係数に基づいて前記類似領域を検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 7 or 8,
The movement vector detection step includes
Calculating the correlation coefficient of the first subchondral bone echo signal and the second subchondral bone echo signal as the similarity, and detecting the similar region based on the correlation coefficient;
Soft tissue cartilage interface detection method. - 請求項7または請求項8に記載の軟組織軟骨境界面検出方法であって、
前記移動ベクトル検出工程は、
前記類似度として、前記第1の軟骨下骨エコー信号と前記第2の軟骨下骨エコー信号のノルムを算出し、該ノルムに基づいて前記類似領域を検出する、
軟組織軟骨境界面検出方法。 The soft tissue cartilage boundary surface detection method according to claim 7 or 8,
The movement vector detection step includes
Calculating the norm of the first subchondral bone echo signal and the second subchondral bone echo signal as the similarity, and detecting the similar region based on the norm;
Soft tissue cartilage interface detection method. - 請求項1乃至請求項10のいずれかに記載の軟組織軟骨境界面検出方法であって、
前記軟骨下骨検出工程は、
前記第1のエコー信号の信号強度を深度方向に沿って表面側から順次取得していき、所定深度に亘り、前記信号強度が軟骨下骨検出用閾値未満であることを検出した後に、前記軟骨下骨検出用閾値以上の信号強度を検出した範囲の信号を、前記第1の状態の軟骨下骨エコー信号として検出し、
前記第1の状態の軟骨下骨エコー信号と前記第2のエコー信号との類似度を検出し、最も類似度の高いエコー信号を前記第2の状態の軟骨下骨エコー信号として検出する、
軟組織軟骨境界面検出方法。 A soft tissue cartilage boundary surface detection method according to any one of claims 1 to 10,
The subchondral bone detection step includes
The signal intensity of the first echo signal is sequentially acquired from the surface side along the depth direction, and after detecting that the signal intensity is less than a subchondral bone detection threshold over a predetermined depth, the cartilage Detecting a signal in a range in which a signal intensity equal to or greater than a threshold value for detecting a lower bone is detected as a subchondral bone echo signal in the first state;
Detecting the similarity between the subchondral bone echo signal in the first state and the second echo signal, and detecting the echo signal having the highest similarity as the subchondral bone echo signal in the second state;
Soft tissue cartilage interface detection method. - 請求項1乃至請求項10のいずれかに記載の軟組織軟骨境界面検出方法であって、
前記軟骨下骨検出工程は、
前記第1のエコー信号の信号強度を深度方向に沿って深部側から順次取得していき、前記軟骨下骨検出用閾値以上の信号強度を検出した範囲の信号を、前記第1の状態の軟骨下骨エコー信号として検出し、
前記第1の状態の軟骨下骨エコー信号と前記第2のエコー信号との類似度を検出し、最も類似度の高いエコー信号を前記第2の状態の軟骨下骨エコー信号として検出する、
軟組織軟骨境界面検出方法。 A soft tissue cartilage boundary surface detection method according to any one of claims 1 to 10,
The subchondral bone detection step includes
The signal intensity of the first echo signal is sequentially acquired from the deep side along the depth direction, and a signal in a range in which a signal intensity equal to or greater than the threshold value for detecting the subchondral bone is detected as the cartilage in the first state. Detect as lower bone echo signal,
Detecting the similarity between the subchondral bone echo signal in the first state and the second echo signal, and detecting the echo signal having the highest similarity as the subchondral bone echo signal in the second state;
Soft tissue cartilage interface detection method. - 軟組織と軟骨の境界面を検出する軟組織軟骨境界面検出装置であって、
第1の状態で超音波信号を被検知体内に送信して第1のエコー信号を出力し、前記第1の状態とは前記軟組織と前記軟骨との位置関係が異なる第2の状態で前記超音波信号を前記被検知体内に送信して第2のエコー信号を出力する送受信部と、
前記第1のエコー信号を用いて前記第1の状態の軟骨下骨エコー信号を検出し、前記第2のエコー信号を用いて前記第2の状態の軟骨下骨エコー信号を検出し、前記第1の状態の軟骨下骨エコー信号と前記第2の状態の軟骨下骨エコー信号とから前記第1の状態から前記第2の状態への軟骨下骨の移動ベクトルを検出し、前記移動ベクトルに基づいて前記第1のエコー信号と前記第2のエコー信号のサンプル位置を補正して、補正後の前記第1のエコー信号と前記第2のエコー信号から前記軟組織と前記軟骨の境界面を検出するデータ解析部と、
を備えることを特徴とする軟組織軟骨境界面検出装置。 A soft tissue cartilage interface detecting device for detecting an interface between soft tissue and cartilage,
In the first state, an ultrasonic signal is transmitted into the body to be detected and a first echo signal is output. The superposition is different in the second state in which the positional relationship between the soft tissue and the cartilage is different from the first state. A transmission / reception unit for transmitting a sound wave signal into the body to be detected and outputting a second echo signal;
Using the first echo signal to detect the subchondral bone echo signal in the first state, using the second echo signal to detect the subchondral bone echo signal in the second state, and A movement vector of the subchondral bone from the first state to the second state is detected from the subchondral bone echo signal in the first state and the subchondral bone echo signal in the second state; Based on this, the sample positions of the first echo signal and the second echo signal are corrected, and the interface between the soft tissue and the cartilage is detected from the corrected first echo signal and the second echo signal. A data analysis unit to
A soft tissue cartilage boundary surface detection device comprising: - 請求項13に記載の軟組織軟骨境界面検出装置であって、
前記送受信部は、走査方向に沿って配列された複数の振動子を備える、
軟骨表面検出装置。 The soft tissue cartilage interface detecting device according to claim 13,
The transmission / reception unit includes a plurality of transducers arranged along a scanning direction,
Cartilage surface detection device. - 請求項13に記載の軟組織軟骨境界面検出装置であって、
前記送受信部は、前記走査方向と、該走査方向と前記超音波信号の送信方向に直交する方向とから規定される領域に二次元的に配列された複数の振動子を備える、
軟組織軟骨境界面検出装置。 The soft tissue cartilage interface detecting device according to claim 13,
The transmission / reception unit includes a plurality of transducers two-dimensionally arranged in a region defined by the scanning direction and a direction orthogonal to the scanning direction and the transmission direction of the ultrasonic signal.
Soft tissue cartilage interface detection device. - 請求項13に記載の軟組織軟骨境界面検出装置であって、
前記送受信部は、単一の振動子と、該振動子を走査方向に移動させる移動機構とを備える、
軟組織軟骨境界面検出装置。 The soft tissue cartilage interface detecting device according to claim 13,
The transmission / reception unit includes a single vibrator and a moving mechanism that moves the vibrator in the scanning direction.
Soft tissue cartilage interface detection device. - 請求項13乃至請求項16のいずれかに記載の軟組織軟骨境界面検出装置であって、
前記走査方向は、前記軟組織と前記軟骨の相対位置を変化させる方向である、
軟組織軟骨境界面検出装置。 The soft tissue cartilage interface detecting device according to any one of claims 13 to 16,
The scanning direction is a direction in which the relative position of the soft tissue and the cartilage is changed.
Soft tissue cartilage interface detection device.
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JPWO2017094397A1 (en) * | 2015-12-04 | 2018-09-20 | 古野電気株式会社 | Ultrasonic analysis apparatus, ultrasonic analysis method, and ultrasonic analysis program |
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CN104837410B (en) | 2017-09-22 |
JPWO2014103512A1 (en) | 2017-01-12 |
CN104837410A (en) | 2015-08-12 |
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