JP6530660B2 - Ultrasonic observation apparatus, operation method of ultrasonic observation apparatus, and operation program of ultrasonic observation apparatus - Google Patents

Description

  The present invention relates to an ultrasonic observation apparatus that observes a tissue to be observed using ultrasonic waves, an operation method of the ultrasonic observation apparatus, and an operation program of the ultrasonic observation apparatus.

  Ultrasound may be applied to observe the characteristics of the biological tissue or material to be observed. Specifically, an ultrasonic wave is transmitted to an observation object, an ultrasonic image is generated based on an ultrasonic echo reflected by the observation object, and the generated ultrasonic image is displayed to observe the observation object. I do.

  As an observation technique of an observation object using an ultrasound image, a technique of superimposing elastic information on hardness of the observation object on an ultrasound image is known (see, for example, Patent Document 1). This technique is called elastography, and based on echo signals, detects distortion of an observation target in a set area (hereinafter referred to as a region of interest), and based on the detected distortion, information on hardness of the observation target is The acquired color information is superimposed on the ultrasonic image as elasticity information according to the hardness. The operator can know the hardness of the observation target by observing the color information of the observation target.

JP 2007-125152 A

  However, in the technology disclosed in Patent Document 1, for example, when the size of the observation target in the ultrasound image changes due to the change in the angle of view of the ultrasound image or the change in the distance from the observation target to the receiving unit of ultrasound. The relative size of the observation target with respect to the region of interest changes, and as a result, the color information related to the observation target changes. As described above, due to the change in the size of the observation target in the ultrasound image, it is not possible to obtain information of constant hardness for the observation target, and the reproducibility of the measurement result related to the elasticity information of the observation target is reduced. Had a problem of

  The present invention has been made in view of the above, and suppresses the decrease in the reproducibility of the measurement result related to the elasticity information of the observation target even when the size of the observation target in the ultrasonic image changes. It is an object of the present invention to provide an ultrasonic observation device, an operation method of the ultrasonic observation device, and an operation program of the ultrasonic observation device.

  In order to solve the problems described above and achieve the object, an ultrasonic observation apparatus according to the present invention transmits ultrasonic waves to an observation target, and uses an ultrasonic transducer that receives ultrasonic waves reflected by the observation target. An image processing unit that generates an ultrasound image based on a received ultrasound signal, and elasticity information of the observation target in a region of interest set in the ultrasound image; and extracting the observation target in the ultrasound image Based on the calculated area of the observation object, the area of the observation object, and the area of the region of interest, the observation object extraction unit calculates the area of the observation object in the ultrasound image. A calculation unit configured to calculate the area of the region of interest; and a region of interest setting unit configured to set the region of interest according to the area of the region of interest calculated by the calculation unit.

  In the ultrasonic observation apparatus according to the present invention, in the above-mentioned invention, the observation target extraction unit extracts an ultrasonic image of a temporally previous frame of the ultrasonic image of the target region setting target, and the extracted ultrasonic image The observation target of the ultrasound image of the target region setting target is extracted based on the reference position of the observation target extracted in the above.

  In the ultrasonic observation apparatus according to the present invention as set forth in the invention described above, the region of interest connects a line segment parallel to the direction of the sound ray forming the ultrasonic image, and ends of the line segment, and the ultrasonic wave It is characterized in that it is a region in which the depths from the surface of the vibrator connect the same position.

  In the ultrasonic observation apparatus according to the present invention as set forth in the invention described above, the region of interest connects a line segment parallel to the direction of the sound ray forming the ultrasonic image, and ends of the line segment, and the ultrasonic wave It is characterized in that it is a fan-shaped area surrounded by a curve connecting the same position from the surface of the vibrator at the same depth.

  In the ultrasonic observation apparatus according to the present invention as set forth in the invention described above, the region of interest setting unit sets a minimum region of interest circumscribing the observation target, and for the minimum region of interest, one of the line segment and the curve is set. The setting of the region of interest is performed by moving at least one and adjusting the size to be the area of the region of interest calculated by the calculation unit.

  In the ultrasound observation apparatus according to the present invention, in the above-mentioned invention, the region of interest setting unit extracts an ultrasound image of a frame in front of an ultrasound image of a region of interest setting target, and is set in the extracted ultrasound image The interest is adjusted by adjusting the size of the region of interest for which the region of interest is to be set to the area of the region of interest calculated by the calculation unit while maintaining a similar relationship to the shape of the region of interest. The setting of the area is performed.

  The ultrasound observation apparatus according to the present invention further includes an input unit configured to receive a setting input for setting the ratio, and the region of interest setting unit is configured to select a region of interest based on the area ratio received by the input unit. The setting of the

  In the ultrasonic observation apparatus according to the present invention, in the above-mentioned invention, control for causing the display device to display the area ratio together with the ultrasonic image in which the region of interest and elasticity information of the observation target in the region of interest are superimposed. The control unit may further include a control unit.

  The operation method of an ultrasonic observation apparatus according to the present invention is an operation method of an ultrasonic observation apparatus that generates an ultrasonic image based on an ultrasonic signal, and the observation target extraction unit performs the observation in the ultrasonic image. An observation target extraction step of extracting an target, a calculation unit calculates an area of the observation target in the ultrasound image, and the calculated area of the observation target, the area of the observation target, and the area of interest A calculation step of calculating the area of the region of interest based on the ratio of areas, and an interest in which the region of interest setting unit sets the region of interest according to the area of the region of interest calculated by the calculation unit The method is characterized by including a region setting step and an image processing step of generating elasticity information of an observation target in the region of interest set in the region of interest setting step.

  The operation program of the ultrasound observation apparatus according to the present invention is an operation program of an ultrasound observation apparatus that generates an ultrasound image based on an ultrasound signal, and the observation target extraction unit performs the observation in the ultrasound image. An observation object extraction procedure for extracting an object, a calculation unit calculates an area of the observation object in the ultrasound image, and the calculated area of the observation object, the area of the observation object, and the area of interest The calculation procedure for calculating the area of the region of interest based on the ratio of areas, and the region of interest setting unit sets the region of interest according to the area of the region of interest calculated by the calculation unit. The ultrasonic observation apparatus is characterized in that the region setting procedure and the image processing procedure in which the image processing unit generates elasticity information of the observation target in the region of interest set in the region of interest setting procedure. That.

  According to the present invention, even when the size of the observation target in the ultrasound image changes, it is possible to suppress the decrease in the reproducibility of the measurement result related to the elasticity information of the observation target.

FIG. 1 is a block diagram showing a configuration of an ultrasound diagnostic system provided with an ultrasound observation apparatus according to an embodiment of the present invention. FIG. 2 is a view schematically showing an observation target and a region of interest in an ultrasound image displayed by the display device of the ultrasound diagnostic system according to the embodiment of the present invention. FIG. 3 is a flowchart showing an outline of processing performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 4 is a view schematically showing an observation target and a region of interest in an ultrasound image displayed by the display device of the ultrasound diagnostic system according to the embodiment of the present invention. FIG. 5 is a diagram for explaining a contour extraction process performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 6 is a diagram for explaining a contour extraction process performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 7 is a view for explaining setting processing of a region of interest performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 8 is a diagram for explaining setting processing of a region of interest performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 9 is a flowchart showing an outline of processing performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 10 is a diagram for explaining follow-up processing of an observation target in a region of interest performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 11 is a diagram for explaining a process of setting a region of interest performed by the ultrasound observation apparatus according to the modification of the embodiment of the present invention. FIG. 12 is a diagram for explaining an example of a region of interest set when the ultrasonic transducer is a linear transducer.

  Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as “embodiment”) will be described with reference to the attached drawings.

Embodiment
FIG. 1 is a block diagram showing a configuration of an ultrasound diagnostic system provided with an ultrasound observation apparatus according to an embodiment of the present invention. The ultrasound diagnostic system 1 shown in the figure transmits an ultrasound to an object to be observed, and receives the ultrasound reflected by the object. The ultrasound endoscope 2 and the ultrasound endoscope 2 The ultrasound observation apparatus 3 which produces | generates an ultrasound image based on the acquired ultrasound signal, and the display apparatus 4 which displays the ultrasound image which the ultrasound observation apparatus 3 produced | generated.

  The ultrasound endoscope 2 converts an electrical pulse signal received from the ultrasound observation apparatus 3 into an ultrasound pulse (acoustic pulse) at its tip and irradiates the subject with an object, and it is reflected by the subject. The ultrasound transducer 21 converts the ultrasound echo into an electrical echo signal (ultrasound signal) that is expressed by a voltage change, and outputs the ultrasound echo signal. The ultrasonic transducer 21 is realized by a radial transducer. The ultrasound endoscope 2 may be one for mechanically scanning the ultrasound transducers 21 or a plurality of elements are provided in an array as the ultrasound transducers 21 and the elements involved in transmission and reception are electronically It may be made to scan electronically by switching or delaying transmission and reception of each element.

  The ultrasound endoscope 2 usually has an imaging optical system and an imaging element, and is inserted into the digestive tract (esophagus, stomach, duodenum, large intestine) or respiratory organ (trachea / bronchus) of a subject and digested It is possible to image a duct, a respiratory organ and its surrounding organs (pancreas, gallbladder, bile duct, biliary tract, lymph nodes, mediastinal organs, blood vessels, etc.). In addition, the ultrasound endoscope 2 has a light guide for guiding illumination light to be irradiated to a subject at the time of imaging. The light guide has a distal end portion reaching the distal end of the insertion portion of the ultrasonic endoscope 2 into the subject, while the proximal end portion is connected to a light source device that generates illumination light.

  The ultrasound observation apparatus 3 includes a transmission / reception unit 31, a signal processing unit 32, an image processing unit 33, a frame memory 34, an observation target extraction unit 35, a calculation unit 36, a region of interest setting unit 37, and an input unit. And a storage unit 39 and a control unit 40.

  The transmitting / receiving unit 31 is electrically connected to the ultrasonic endoscope 2 and transmits a transmission signal (pulse signal) consisting of high voltage pulses to the ultrasonic transducer 21 based on a predetermined waveform and transmission timing. An echo signal, which is an electrical reception signal, is received from the sound wave vibrator 21 to generate and output digital radio frequency (RF) signal data (hereinafter referred to as RF data).

  The frequency band of the pulse signal transmitted by the transmission / reception unit 31 may be a wide band that substantially covers the linear response frequency band of the electroacoustic conversion of the pulse signal in the ultrasonic transducer 21 to the ultrasonic pulse.

  The transmitting and receiving unit 31 transmits various control signals output from the control unit 40 to the ultrasound endoscope 2 and receives various information including an identification ID from the ultrasound endoscope 2 to control the control unit 40. It also has a function to send to.

  In addition, when the transmission / reception unit 31 acquires control information indicating that elastography is to be performed from the control unit 40, the transmission signal including high voltage pulses based on the waveform and transmission timing for obtaining the B mode image and the image related to elastography. (Pulse signal) is transmitted to the ultrasonic transducer 21. Specifically, the transmission / reception unit 31 superimposes a pulse for elastography on a pulse for acquiring a B-mode image, for example. The transmission / reception unit 31 transmits an ultrasonic wave in the same direction a plurality of times, and receives a plurality of reflected echo signals to acquire an echo signal for elastography. When receiving the echo signal for elastography, the transmission / reception unit 31 generates RF data for elastography and outputs it to the image processing unit 33.

  The signal processing unit 32 generates digital B mode reception data based on the RF data received from the transmission / reception unit 31. Specifically, the signal processing unit 32 performs known processing such as a band pass filter, envelope detection, logarithmic conversion, and the like on the RF data to generate digital B mode reception data. In logarithmic conversion, the common logarithm of the amount obtained by dividing RF data by the reference voltage is taken and expressed as a decibel value. The B-mode reception data consists of a plurality of line data in which the amplitude or intensity of the reception signal indicating the intensity of the reflection of the ultrasonic pulse is arranged along the transmission / reception direction (depth direction) of the ultrasonic pulse. The signal processing unit 32 outputs the generated B frame reception data for one frame to the image processing unit 33.

  In addition, the signal processing unit 32 generates elastography reception data based on the elastography RF data received from the transmission / reception unit 31. Specifically, using the RF data in the same direction, the signal processing unit 32 calculates the change in the amplitude or the intensity of the received signal indicating the intensity of the reflection of the ultrasonic pulse for each predetermined depth, and performs the calculation. An acoustic ray (line data) having a variable amount of change is generated. The reception data for elastography comprises a plurality of line data in which the amount of change in amplitude or intensity of the reception signal indicating the intensity of reflection of the ultrasonic pulse is arranged along the transmission / reception direction (depth direction) of the ultrasonic pulse. The signal processing unit 32 is realized by using a central processing unit (CPU), various arithmetic circuits, and the like.

  The image processing unit 33 generates B-mode image data based on the B-mode reception data received from the signal processing unit 32. The image processing unit 33 performs signal processing on the B-mode reception data output from the signal processing unit 32 using known techniques such as scan converter processing, gain processing, contrast processing, etc. B-mode image data is generated by thinning out data according to the data step width determined according to the display range of the image. In the scan converter process, the scan direction of the B mode reception data is converted from the scan direction of the ultrasonic waves to the display direction of the display device 4. The B-mode image is a grayscale image in which the values of R (red), G (green), and B (blue), which are variables when an RGB color system is adopted as a color space, are matched. The image generated by the image processing unit 33 is larger than the display area that can be displayed by the display device 4. In other words, the B mode image displayed on the display device 4 is a part of the B mode image generated by the image processing unit 33.

  Further, the image processing unit 33 generates elastography image data based on the elastography reception data received from the signal processing unit 32. Specifically, the image processing unit 33 generates elastography image data by giving color information to each depth position in accordance with the relative amount of change in the set region of interest. The color information is elasticity information indicating the hardness of the observation target at each position, and is information represented by a color relatively determined by the rate of change in the region of interest.

  The image processing unit 33 performs coordinate transformation on the B-mode reception data and the elastography reception data from the signal processing unit 32 so that the scanning range can be spatially correctly expressed, and then, between the B-mode reception data, And the gap between the B-mode received data is filled by performing interpolation processing between the received data for elastography and B-mode image data and elastography image data are generated.

  The image processing unit 33 generates display image data by superimposing the elastography image data on the generated B-mode image data.

  The frame memory 34 is realized by using, for example, a ring buffer, and stores B-mode image data of one frame generated by the image processing unit 33 in chronological order. The frame memory 34 may store B-mode image data of a plurality of frames in chronological order. In this case, when the frame memory 34 runs out of capacity (when B-mode image data of a predetermined number of frames is stored), the latest B-mode image data is overwritten with the latest B-mode image data, thereby the latest B-mode image data. A predetermined number of frames of image data are stored in chronological order.

  The observation target extraction unit 35 extracts the outline of the observation target including the designated point input through the input unit 38 and the designated point in the observation target extracted in the previous frame. The outline extraction process performed by the observation target extraction unit 35 will be described later.

  The calculation unit 36 calculates the area of the region of interest (ROI) based on the area of the observation target extracted by the observation target extraction unit 35 and the set area ratio.

  The region of interest setting unit 37 sets the region of interest based on the arrangement of the observation target extracted by the observation target extraction unit 35 and the area calculated by the calculation unit 36. The region of interest setting process performed by the region of interest setting unit 37 will be described later.

FIG. 2 is a view schematically showing an observation target and a region of interest in an ultrasound image displayed by the display device of the ultrasound diagnostic system according to the embodiment of the present invention. When the contour of the observation target S is extracted by the observation target extraction unit 35 and the area of the observation target S is calculated by the calculation unit 36, the region of interest setting unit 37 includes the observation target S as shown in FIG. to set the region of interest R _10. In the present embodiment, the region-of-interest setting unit 37 includes, in the B-mode image W1, a line segment parallel to the depth D direction (sound ray direction) from the center of the image 210 of the ultrasonic transducer 21; end tied to each other, and the depth from the surface of the ultrasonic transducer 21 (image 210) is to set the region of interest R ₁₀ is a fan-shaped area enclosed by a curve formed by connecting the same position. The “curved line” referred to here corresponds to the scanning direction of the ultrasonic transducer 21.

  The input unit 38 is realized by using a user interface such as a keyboard, a mouse, a trackball, and a touch panel, and receives an input of various information. The input unit 38 outputs the received information to the control unit 40.

  The storage unit 39 stores various programs for operating the ultrasound diagnostic system 1, data including various parameters necessary for the operation of the ultrasound diagnostic system 1, and the like. The storage unit 39 includes a region-of-interest setting information storage unit 391 that stores region-of-interest setting information that is information related to setting of a region of interest. The region of interest setting information is information for specifying the size of the region of interest to be set for the observation target, and more specifically, information on the ratio (area ratio) of the area of the observation target to the area of the region of interest It contains.

  In addition, the storage unit 39 stores various programs including an operation program for executing the operation method of the ultrasound diagnostic system 1. The operation program can also be widely distributed by being recorded on a computer readable recording medium such as a hard disk, flash memory, CD-ROM, DVD-ROM, flexible disk and the like. Note that the various programs described above can also be acquired by downloading via a communication network. The communication network referred to here is realized by, for example, an existing public line network, a local area network (LAN), a wide area network (WAN) or the like, and may be wired or wireless.

  Storage unit 39 having the above configuration is realized using a ROM (Read Only Memory) in which various programs and the like are previously installed, and a RAM (Random Access Memory) and the like storing operation parameters and data of each process. .

  The control unit 40 controls the entire ultrasound diagnostic system 1. The control unit 40 is realized by using a CPU having arithmetic and control functions, various arithmetic circuits, and the like. The control unit 40 reads out the information stored in the storage unit 39 and stored from the storage unit 39 and executes various arithmetic processing related to the operation method of the ultrasound observation apparatus 3 to control the ultrasound observation apparatus 3 collectively. Do. It is also possible to configure the control unit 40 using a CPU or the like common to the signal processing unit 32.

  FIG. 3 is a flowchart showing an outline of processing performed by the ultrasound observation apparatus according to the embodiment of the present invention, in which an observation target of elastography display target is specified and a region of interest corresponding to the observation target is set. It is a flowchart explaining the process to be performed. First, the control unit 40 determines whether a designated point for designating as an observation target has been input to the B-mode image (step S101).

FIG. 4 is a view schematically showing an observation target and a region of interest in an ultrasound image displayed by the display device of the ultrasound diagnostic system according to the embodiment of the present invention. Control unit 40, as shown in FIG. 4, in the B-mode image W10, designated point P ₁ that specifies the observation target S to determine whether or not the input. Control unit 40, when the designated point P ₁ is determined not to be input (step S101: No), repeats the input confirmation of a specified point P _1. On the other hand, the control unit 40, when the designated point P ₁ is determined to have been input (step S101: Yes), the process proceeds to step S102.

In step S102, the observation target extracting unit 35, based on the luminance value at the specified point P _1, binarizing the B-mode image data. FIG. 5 is a diagram for explaining contour extraction processing performed by the ultrasound observation apparatus according to the embodiment of the present invention, and is a diagram showing a histogram regarding the number of pixels of the luminance value. The observation target extraction unit 35 generates a histogram related to the number of pixels of the luminance value as shown in FIG. Observation target extracting unit 35 obtains a standard deviation by referring to the data relating to the histogram, extracting a range of ± 3 [sigma] of the luminance values of the designated point P ₁ (range D _{3 [sigma]} shown in FIG. 5).

  FIG. 6 is a diagram for explaining contour extraction processing performed by the ultrasound observation apparatus according to the embodiment of the present invention, and is a diagram for explaining binarization of B-mode image data. The observation target extraction unit 35 sets, for example, an area corresponding to the extracted range to white (maximum luminance value) as in the binarized image W11 shown in FIG. 6, and an area outside the extraction range to black (luminance value B mode image data is binarized by setting to 0).

Thereafter, the observation target extraction unit 35 extracts the boundary of the luminance value of the binarized B-mode image data (a boundary having different luminance values) (step S103: observation target extraction step). Thus, the contour of the observed object S specified by the designated point P ₁ is extracted.

  When the contour of the observation target S is extracted, the calculation unit 36 calculates the area of the observation target S (step S104: calculation step). The calculation unit 36 calculates the area (referred to as area S1) of the part surrounded by the extracted outline (boundary).

  After that, the calculation unit 36 sets the region of interest to be set for the extracted observation object S based on the calculated area S1 of the observation object S and the area ratio stored in the region of interest setting information storage unit 391. The area (referred to as an area S2) of the above is calculated (step S105: calculation step).

  When the area of the region of interest is calculated by the calculation unit 36, the region of interest setting unit 37 sets the region of interest by specifying the position of the region of interest with respect to the observation target S (step S106: region of interest setting step) .

FIGS. 7 and 8 are diagrams for explaining a process of setting a region of interest performed by the ultrasound observation apparatus according to the embodiment of the present invention. The region-of-interest setting unit 37 is an arc that connects two straight lines parallel to the direction of the sound ray and circumscribed with the observation target S and connecting both ends of the two straight lines with equal depths. to produce a minimum area of interest R ₁₁ fan-shaped is formed by the two curves in contact with the observation object S (see B-mode image W2 in Fig. 7). ROI setting unit 37, based on the minimum area of interest R _11, gradually increasing the area of interest so that the area is S2.

  The region of interest setting unit 37 may enlarge the region of interest by moving a straight line parallel to the sound ray in a direction away from the observation target, for example, or the position of the curve in the depth direction is separated from the observation target The region of interest may be enlarged by moving in the direction, or the region of interest may be enlarged while moving the straight line and the curve respectively.

ROI setting unit 37, the area of the region of interest is gradually increased until S2, and sets an area became area S2 as a region of interest R ₁₂ for observation target S (see B-mode image W3 in FIG. 8) .

Control unit 40, after setting the ROI by the ROI setting unit 37, the image processing unit 33, to generate an elastographic image data for the set region of interest R ₁₂ (image processing step), the region of interest R ₁₂ The display device 4 that has received the B-mode image data on which the elastography image (color information) is superimposed displays the B-mode image corresponding to the B-mode image data (step S107). At this time, the display device 4 may display the set area ratio (S1 / S2).

  Subsequently, a process of setting the region of interest for the observation target designated as the tracking target by making the observation target S designated in the processing shown in FIG. 3 follow the B-mode image data of the next frame and thereafter will be described. FIG. 9 is a flowchart showing an outline of processing performed by the ultrasound observation apparatus according to the embodiment of the present invention. FIG. 10 is a diagram for explaining follow-up processing of an observation target in a region of interest performed by the ultrasound observation apparatus according to the embodiment of the present invention.

After extracting the observation target S based on the specified point P ₁ as described above, the B-mode image data of the next frame of the B-mode image data inputted to finger fixed point P _1, to follow the observation target S, and follow When setting the region of interest for the observation target S, the observation target extraction unit 35 first refers to the frame memory 34 to determine the B mode of the frame temporally preceding the B mode image data of the region of interest setting target. As image data, B-mode image data one frame before is extracted (step S201). The extracted B-mode image data, such as the B-mode image W12 shown in (a) of FIG. 10, the observation target S, the information between the designated point P ₁ which is input is assigned.

The observation target extraction unit 35 extracts the center or center of gravity position of the observation target S as a reference position based on the contour of the observation target S (step S202). For example, as shown in (b) of FIG. 10, the observation target extraction unit 35 sets a rectangular area circumscribing the observation target S, calculates the center position of the rectangle, and calculates the calculated center (centroid) position. It is extracted as a center (center of gravity) position P ₂ of the observation target S. In addition to the center (center of gravity) position, a position that satisfies the conditions set for the observation target may be used as the reference position. For example, when the observation target has a concave shape and the center position does not exist in the observation target, the edge closest to the observation target from the center position or the inside thereof may be used as the reference position.

Thereafter, the observation target extracting unit 35, as shown in (c) of FIG. 10, B-mode image of the region of interest setting target, i.e., the center position P ₂ in the B-mode image W13 of the next frame of the B-mode image W12 in accordance coordinate to locate the specified point P _3. After placement of the designated point P ₃ is the observation target extracting unit 35, as described above observation target extracting process (Step S 102 to S 104), the extraction process to be observed, including the designation point P ₃ (observation target extracting step) Do.

Specifically, the observation target extracting unit 35, based on the luminance value at the specified point P _3, binarizing the B-mode image data (step S203). Observation target extracting unit 35 generates a histogram of the number of pixel intensity values as shown in FIG. 5, to extract a range of ± 3 [sigma] of the luminance values of the specified point P _3. The observation target extraction unit 35 sets the region corresponding to the extracted range to white (maximum luminance value) and sets the region out of the extraction range to black (luminance value 0) to obtain B-mode image data. Make it valuable.

Thereafter, the observation target extraction unit 35 extracts the boundary of the luminance value of the binarized B-mode image data (the boundary having different luminance values) (step S204). Thus, the contour of the observed object S specified by the specified point P ₃ is extracted.

  When the contour of the observation target S is extracted, the calculation unit 36 calculates the area of the observation target S (step S205). The calculation unit 36 calculates the area S1 of the part surrounded by the extracted outline.

  After that, the calculation unit 36 sets the region of interest to be set for the extracted observation object S based on the calculated area S1 of the observation object S and the area ratio stored in the region of interest setting information storage unit 391. To calculate the area S2 of (step S206: calculation step).

  When the area of the region of interest is calculated by the calculation unit 36, the region of interest setting unit 37 sets the region of interest by specifying the position of the region of interest with respect to the observation target S (step S207: region of interest setting step) .

  After setting the region of interest by the region of interest setting unit 37, the control unit 40 causes the image processing unit 33 to generate elastography image data for the set region of interest (image processing step), and an elastography image of the region of interest The display device 4 that has received the B mode image data on which (color information) is superimposed displays the B mode image corresponding to the B mode image data (step S208).

Thus, find the center (gravity center) position P ₂ of the specified observation object S by the designated point P _1, specifies the designated point P ₃ corresponding to the central to the B-mode image of the next frame (gravity center) position P ₂ By doing this, the observation target S specified in the previous frame can be made to follow even in the next frame. Thereafter, the area S1 of the observed object to be followed is calculated, and the area of interest in the next frame is set by comparing the area ratio with the area ratio. Similar follow-up processing and setting processing of the region of interest are performed on the B-mode image of the subsequent frame. Therefore, it is possible to follow even if the position of the previous frame and the observation target is different, and the region of interest is set each time even if the size (area) of the observation target of the previous frame is different. The color information determined by the relative relationship between the size of and the size of the observation target can be made constant between frames.

  According to the embodiment of the present invention described above, the area S1 of the observation target is calculated, and the region of interest is set to have a predetermined area ratio with respect to the area S1. Even if the area of the observation target changes, the area ratio between the observation target and the region of interest can be made constant. As a result, color information (elastography image) determined by the relative relationship between the size of the region of interest and the size of the observation target is made constant between frames, and the measurement result according to the information (elasticity information) of the hardness of the observation target It is possible to suppress the decrease in the reproducibility of

  Further, according to one embodiment of the present invention, in the B-mode image data of the region of interest setting target, the center (centroid) position of the observation target extracted in the previous frame in time is determined, and the center (centroid) Since the observation target in the B-mode image data of the region of interest setting target is specified based on the position, the same observation target between the frames can be automatically extracted and followed.

  In the embodiment described above, the B-mode image data of one frame before is extracted and the following processing of the observation target is performed based on the designated point in the extracted B-mode image data. The B-mode image data before the frame may be extracted, or the designated B-mode image data may be extracted.

In the embodiment described above, two straight lines parallel to the sound ray and circumscribed to the observation target S and arcs connecting both ends of the two straight lines with equal depths are connected. has been described as moving at least one of the two curves in contact with the observation object S to increase the area of interest for the minimum area of interest R _11, the process of setting the region of interest is not limited to this . For example, the area of the region of interest may be adjusted by extracting a previously stored region of interest of a predetermined size, and making the region of interest larger or smaller. At this time, the shape of the region of interest is not limited to a fan shape, and for example, the operator sets the area increasing or decreasing area of the region of interest via the input unit 38, and the shape of the region of interest according to the area May be adjusted. In addition to the setting method described above, the setting of the region of interest may be formed based on the set and input conditions.

  Further, in the embodiment described above, in addition to the area ratio stored in the region of interest setting information storage unit 391, the area ratio set and input by the operator via the input unit 38 may be appropriately adopted. .

  Further, in the embodiment described above, the shape of the region of interest is not limited to the fan shape, and may be a square shape, a circle, an oval shape, or the like. The region of interest setting unit 37 sets the region of interest so as to obtain the calculated area by adjusting the set place with respect to the set shape.

(Modification of the embodiment)
Subsequently, a modification of the embodiment of the present invention will be described. FIG. 11 is a diagram for explaining a process of setting a region of interest performed by the ultrasound observation apparatus according to the modification of the embodiment of the present invention. In the above-described embodiment, two straight lines parallel to the sound ray and circumscribed to the observation target S, and arcs connecting both ends of the two straight lines with equal depths are formed. has been described as to increase the area of interest for the minimum area of interest R ₁₁ is moved at least one of the two curves in contact with the object S, in this modification, the shape of the minimum region of interest R ₁₁ While maintaining it, the region of interest is expanded to a predetermined area. That is, a relation between the minimum ROI R ₁₁ and after setting the ROI, analogous relation holds.

Specifically, the region of interest setting unit 37 extracts the region of interest set in the previous frame, for example, the region of interest R ₁₀ of the B mode image W1 shown in FIG. depending on the area of the set region of interest, while maintaining the shape of the region of interest R _10, it is adjusted to a predetermined area. Thereby, the region of interest R ₁₃ in which the area ratio is maintained can be set for the observation target S in the B-mode image W 4 shown in FIG. Note that when the region of interest protrudes from the display screen, the color information can be made constant between frames by generating color information related to elastography, including the region of interest that has overflowed. Even if the region of interest is larger than the display region, only a part of the region of interest is displayed for display, but the area of all regions of interest is used for elastography calculation.

  Also in the present modification, the shape of the region of interest is not limited to the fan-like shape, and may be angular, circular, or elliptical. The region of interest setting unit 37 sets the region of interest so as to obtain the calculated area while maintaining a similar relationship to the set shape.

  Although the embodiments for carrying out the present invention have been described above, the present invention should not be limited only by the above-described embodiments. For example, although it has been described by way of example that the observation target is a living tissue, the present invention can be applied to an industrial endoscope that observes the characteristics of a material. The ultrasonic observation apparatus according to the present invention is applicable to either the inside or the outside of the body. In addition to ultrasonic waves, infrared rays may be irradiated to transmit and receive signals to be observed.

  In the ultrasonic observation apparatus, the circuits having the respective functions may be connected by a bus, or some of the functions may be incorporated in the circuit structure of the other functions. .

  In the present embodiment, the ultrasonic probe is described using an ultrasonic endoscope having an optical system such as a light guide. However, the present invention is not limited to the ultrasonic endoscope and does not have an imaging optical system and an imaging element. It may be an ultrasonic probe. Furthermore, as an ultrasonic probe, an ultrasonic miniature probe with a small diameter without an optical system may be applied. The ultrasonic miniature probe is usually inserted into the biliary tract, biliary duct, pancreatic duct, trachea, bronchus, urethra, ureter and used to observe surrounding organs (pancreas, lung, prostate, bladder, lymph nodes, etc.).

  In addition, as an ultrasound probe, an extracorporeal ultrasound probe that applies ultrasound from the body surface of the subject may be applied. Extracorporeal ultrasound probes are usually used in direct contact with the body surface when observing abdominal organs (liver, gallbladder, bladder), breast (especially mammary gland), thyroid.

The ultrasonic transducer may be a linear transducer, a radial transducer, or a convex transducer. When the ultrasonic transducer is a linear transducer, its scanning area is rectangular (rectangular, square), and when the ultrasonic transducer is a radial transducer or a convex transducer, its scanning area Are fan-shaped or ring-shaped. FIG. 12 is a diagram for explaining an example of a region of interest set when the ultrasonic transducer is a linear transducer. If ultrasonic vibrator is a linear type vibrator, for example, with respect to the observation object S in the B-mode image W5 shown in FIG. 12, the region of interest R ₁₄ forming a rectangle is set. In addition, the ultrasound endoscope may mechanically scan the ultrasound transducers, or a plurality of elements are provided in an array as the ultrasound transducers, and the elements involved in transmission and reception are switched electronically. Alternatively, scanning may be performed electronically by delaying transmission and reception of each element.

  Thus, the present invention can include various embodiments without departing from the technical concept described in the claims.

Reference Signs List 1 ultrasound diagnostic system 2 ultrasound endoscope 3 ultrasound observation apparatus 4 display device 21 ultrasound transducer 31 transmission / reception unit 32 signal processing unit 33 image processing unit 34 frame memory 35 observation target extraction unit 36 calculation unit 37 region of interest setting Unit 38 Input unit 39 Storage unit 40 Control unit 391 Region of interest setting information storage unit

Claims (9)

An ultrasonic image based on an ultrasonic signal received from an ultrasonic transducer that transmits an ultrasonic wave to an observation object and receives an ultrasonic wave reflected by the observation object, and in a region of interest set in the ultrasonic image An image processing unit that generates elasticity information of the observation target;
The ultrasound image of the temporally previous frame of the ultrasound image of the region of interest setting object is extracted, and based on the reference position of the observation object extracted in the extracted ultrasound image, the ultrasound image of the object of interest region setting object is An observation target extraction unit that extracts an observation target of an acoustic image ;
The area of the region of interest is calculated based on the calculated area of the object to be observed and the area of the region to be observed and the area of the region of interest while calculating the area of the object to be observed in the ultrasound image. A calculation unit that calculates
A region of interest setting unit configured to set the region of interest in accordance with the area of the region of interest calculated by the calculation unit;
An ultrasonic observation device characterized by comprising. The region of interest connects a line segment parallel to the direction of the sound ray forming the ultrasound image and the ends of the line segment and connects the same position from the surface of the ultrasound transducer at the same depth. The ultrasonic observation device according to claim 1, wherein the region is The region of interest connects a line segment parallel to the direction of the sound ray forming the ultrasound image and the ends of the line segment and connects the same position from the surface of the ultrasound transducer at the same depth. The ultrasonic observation apparatus according to claim 1, wherein the ultrasonic observation apparatus is a fan-shaped area surrounded by the curved lines. The region of interest setting unit sets a minimum region of interest circumscribing the observation target, moves at least one of the line segment and the curve with respect to the minimum region of interest, and calculates the interest calculated by the calculation unit. The ultrasonic observation apparatus according to claim 3, wherein the region of interest is set by adjusting the size to be the area of the region. The region of interest setting unit extracts an ultrasound image of a previous frame of the ultrasound image of the region of interest setting target, and maintains a similar relationship to the shape of the region of interest set in the extracted ultrasound image. The setting of the region of interest is performed by adjusting the size of the region of interest of the region of interest setting target to a size that is the area of the region of interest calculated by the calculation unit. The ultrasonic observation apparatus of description. It further comprises an input unit for receiving a setting input for setting the ratio of the areas,
The ultrasound observation apparatus according to claim 1, wherein the region of interest setting unit sets the region of interest based on the ratio of the areas received by the input unit. The region of interest, and the superimposed elastic information of the observation target in the function center region with ultrasound images, claims and further comprising a control unit which performs control to display the ratio of the area on a display device The ultrasound observation apparatus of claim 1. An operation method of an ultrasound observation apparatus for generating an ultrasound image based on an ultrasound signal, comprising:
The observation target extraction unit extracts an ultrasonic image of a temporally previous frame of the ultrasonic image of the target region setting target, and based on the reference position of the observation target extracted in the extracted ultrasonic image, An observation target extraction step of extracting an observation target of an ultrasound image of a target region setting target ;
Calculation unit, calculates the area of the observation target in the ultrasound image, based on the area of the observation target issued the calculated and the ratio of the area of the area and associated cardiac region of the observation target, the Calculating the area of the region of interest;
An area of interest setting step of setting the area of interest according to the area of the area of interest calculated by the calculation unit;
An image processing step of generating elasticity information of an observation target in the region of interest set in the region of interest setting step;
A method of operating an ultrasonic observation apparatus, comprising: An operating program of an ultrasonic observation apparatus for generating an ultrasonic image based on an ultrasonic signal, comprising:
The observation target extraction unit extracts an ultrasonic image of a temporally previous frame of the ultrasonic image of the target region setting target, and based on the reference position of the observation target extracted in the extracted ultrasonic image, An observation target extraction procedure for extracting an observation target of an ultrasound image of a target region setting target ;
Calculation unit, calculates the area of the observation target in the ultrasound image, based on the area of the observation target issued the calculated and the ratio of the area of the area and associated cardiac region of the observation target, the Calculation procedure for calculating the area of the region of interest;
A region of interest setting step of setting the region of interest according to the area of the region of interest calculated by the calculation unit;
An image processing procedure of generating elasticity information of an observation target in the region of interest set in the region of interest setting procedure;
An operating program for the ultrasonic observation apparatus, which is executed by the ultrasonic observation apparatus.

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