JP2014045943A - Ultrasound diagnostic apparatus and correction method of image data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic apparatus which does not require positioning even when a transmitter or an object to be detected moves.SOLUTION: The ultrasound diagnostic apparatus includes a position information acquisition part which includes sensors attached to a transmitter, an ultrasonic probe, a fixing position, and an object to be detected respectively, receives a reference signal from the transmitter, and acquires position information on three-dimensional spaces of the respective sensors, and the ultrasound diagnostic apparatus positions an arbitrary cross section of the three-dimensional image data and a cross section scanned by an ultrasonic probe on the basis of position information of the three-dimensional image data obtained by another medical image diagnostic apparatus and the ultrasonic probe. The ultrasonic diagnostic apparatus also calculates an amount of movement of the transmitter and a movement amount of the object to be detected and corrects positional deviation between the cross section of the three-dimensional image data and the cross section scanned by the ultrasonic probe on the basis of the movement amount of the transmitter and the amount of movement of the object to be detected.

Description

  Embodiments described herein relate generally to an ultrasound diagnostic apparatus that acquires an ultrasound image using an ultrasound probe, and a cross-sectional image and ultrasound of image data acquired by another medical image diagnostic apparatus using a position sensor system. The present invention relates to an ultrasonic diagnostic apparatus that aligns images and supports diagnosis and treatment of a disease, and an image data correction method.

  Conventionally, an ultrasonic diagnostic apparatus is used as a medical apparatus. The ultrasonic diagnostic apparatus can be connected to various modalities such as an X-ray CT apparatus (X-ray computed tomography apparatus) and an MRI apparatus (magnetic resonance imaging apparatus) via a hospital network. Diagnosis and treatment of diseases are supported by using images acquired by other medical image diagnostic apparatuses.

  For example, a cross section scanned by an ultrasound probe and a CT image or MRI image in which a lesion is detected are aligned using a magnetic position sensor, and the position of the lesion is determined using the CT image or MRI image as a reference image. In addition, an ultrasonic diagnostic apparatus for navigating an ultrasonic probe is known. The magnetic position sensor is provided in a magnetic field formed by a transmitter, for example, and is attached to the ultrasonic probe.

  In alignment using the position sensor system, it is assumed that the transmitter is a reference for the position / angle information (the origin of the coordinate system), and the transmitter does not move. However, when the positioning is completed and inspection / treatment by the ultrasonic diagnostic apparatus is started, if the transmitter position is moved by mistake, the reference of the position / angle information will be shifted, and the cross section of the ultrasonic scan will be Deviation occurs in the cross section of the reference image. In addition, when the subject moves, the alignment state is lost, and there is a risk of performing an erroneous examination or treatment.

JP-A-10-151131

  The problem to be solved by the invention is to provide an ultrasonic diagnostic apparatus and an image data correction method that can eliminate the need for alignment even when a transmitter or a subject moves.

  The ultrasonic diagnostic apparatus according to the embodiment is attached to a transmitter that transmits a reference signal in a three-dimensional space, a first sensor attached to an ultrasonic probe, a second sensor attached to a fixed position, and a subject. A position information acquisition unit that includes a third sensor and receives the reference signal to acquire position information of each sensor in the three-dimensional space; three-dimensional image data generated by a medical image diagnostic apparatus; Based on the position information of the ultrasonic probe acquired by one sensor, an arbitrary cross section of the three-dimensional image data is aligned with a cross section scanned by the ultrasonic probe, and the three-dimensional image data Detecting that the position of the transmitter has changed based on the association information that associates the three-dimensional space with the position information acquired by the second sensor; Based on the first position calculation unit that calculates the movement amount of the transmitter and the position information acquired by the third sensor, the movement of the subject is detected and the movement amount of the subject is calculated. A second position calculation unit, and a correction unit that corrects a positional deviation between a cross section of the three-dimensional image data and a cross section scanned by the ultrasonic probe based on the movement amount of the transmitter and the movement amount of the subject. And a display unit for displaying an image based on the three-dimensional data and an ultrasonic image scanned by the ultrasonic probe.

1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to an embodiment. Explanatory drawing which shows schematically arrangement | positioning of the position sensor in one Embodiment. The figure which shows the reference image and ultrasonic image after the alignment in one Embodiment. Explanatory drawing which shows the operation | movement of the position alignment of the image in the case of performing an ultrasonic diagnosis by making MPR image in one Embodiment into a reference image. 1 is a block diagram showing a specific configuration of an ultrasonic diagnostic apparatus according to an embodiment. Explanatory drawing which shows the 1st correction | amendment process when a transmitter moves in one Embodiment. Explanatory drawing which shows the correction | amendment process when a subject moves in one Embodiment. Explanatory drawing which shows the 2nd correction | amendment process when a transmitter moves in one Embodiment. The flowchart which shows the operation | movement procedure of the ultrasonic diagnosing device in one Embodiment.

  Hereinafter, an ultrasonic diagnostic apparatus according to an embodiment will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected about the same location.

(First embodiment)
FIG. 1 is a block diagram illustrating a schematic configuration of an ultrasonic diagnostic apparatus 10 according to an embodiment. In FIG. 1, a main body 100 of an ultrasonic diagnostic apparatus includes an ultrasonic probe 11 that transmits / receives ultrasonic waves to / from a subject (not shown) and an ultrasonic probe 11 that drives the ultrasonic probe 11 to A transmission / reception unit 12 that performs acoustic wave scanning and a data processing unit 13 that processes reception signals obtained by the transmission / reception unit 2 to generate image data such as B-mode image data and Doppler image data are provided.

 The main body 100 also collects and stores the image generation unit 14 that generates two-dimensional image data based on the image data output from the data processing unit 13 and the image data generated by the image generation unit 14. An image memory 15 is provided.

 The main body 100 further includes a control unit 16 that controls the entire apparatus, a storage unit 17, and an interface unit 18 for connecting the main body 100 to the network 200. The interface 18 is connected to an input unit 19 for inputting various command signals and the like, and a position information acquisition unit 20. The main body 100 is connected to a monitor (display unit) 21 that displays an image generated by the image generation unit 14. The control unit 16 and each circuit unit are connected via a bus line 22.

 The interface 18 can be connected to the network 200 and can store image data acquired by the ultrasonic diagnostic apparatus 10 in an external medical server 201 via the network 200. Note that a medical image diagnostic apparatus 202 such as an MRI apparatus or an X-ray CT apparatus is connected to the network 200, and medical image data acquired by the MRI apparatus or the X-ray CT apparatus can be stored in the medical server 201. it can.

  The ultrasonic probe 11 is for transmitting and receiving ultrasonic waves by bringing its tip surface into contact with the body surface of the subject, and has, for example, a plurality of piezoelectric vibrators arranged one-dimensionally. The piezoelectric vibrator is an electroacoustic transducer, which converts an ultrasonic drive signal into a transmission ultrasonic wave during transmission, and converts a reception ultrasonic wave from the subject into an ultrasonic reception signal during reception. For example, the ultrasonic probe 11 is a sector type, linear type or convex type ultrasonic probe.

 The transmission / reception unit 12 includes a transmission unit 121 that generates an ultrasonic drive signal and a reception unit 122 that processes an ultrasonic reception signal obtained from the ultrasonic probe 11. The transmission unit 121 transmits an ultrasonic drive signal. The signal is generated and output to the ultrasonic probe 11, and the receiving unit 122 outputs an ultrasonic reception signal from the piezoelectric vibrator to the data processing unit 13. When ultrasonic waves are transmitted from the ultrasonic probe 11 to the subject, the transmitted ultrasonic waves are successively reflected by the discontinuous surface of the acoustic impedance in the body tissue of the subject, and a plurality of piezoelectric vibrations are reflected as reflected wave signals. Received by the child.

 The amplitude of the reflected wave signal received by the piezoelectric vibrator depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. The reflected wave signal when the transmitted ultrasonic pulse is reflected by the moving blood flow or the surface of the heart wall depends on the velocity component of the moving object in the ultrasonic transmission direction due to the Doppler effect. , Subject to frequency shift.

  As the ultrasonic probe 11 in this embodiment, when a subject is scanned two-dimensionally with a one-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are arranged in a line, or a plurality of piezoelectric vibrators of a one-dimensional ultrasonic probe This is applicable even when the device is mechanically swung. The present invention can also be applied to a case where a subject is scanned three-dimensionally with a two-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are two-dimensionally arranged in a lattice shape.

  The receiving unit 122 includes an amplifier circuit, an A / D converter, an adder, and the like, and performs various processes on the reflected wave signal received by the ultrasonic probe 11 to generate reflected wave data. The amplifier circuit amplifies the reflected wave signal for each channel and performs gain correction processing. The A / D converter provides a delay time necessary for A / D converting the gain-corrected reflected wave signal to determine the reception directivity. The adder performs an addition process of the reflected wave signal processed by the A / D converter to generate reflected wave data. By the addition processing of the adder, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is emphasized.

  Thus, the transmission / reception unit 12 controls transmission directivity and reception directivity in transmission / reception of ultrasonic waves. Further, the transmission / reception unit 12 has a function capable of instantaneously changing delay information, transmission frequency, transmission drive voltage, number of aperture elements, and the like under the control of the control unit 16.

 The data processing unit 13 includes a B mode processing unit 131 that generates B mode image data from a signal output from the transmission / reception unit 12, and a Doppler processing unit 132 that generates Doppler image data. The B mode processing unit 131 performs envelope detection on the signal from the transmission / reception unit 12 and then performs logarithmic conversion, converts the logarithmically converted signal into a digital signal, generates B mode image data, and generates the image generation unit 14. Output to.

  The Doppler processing unit 132 detects the Doppler shift frequency for the signal from the transmission / reception unit 12 and converts it to a digital signal, and then extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and average velocity, dispersion, Data (Doppler data) obtained by extracting moving body information such as power for multiple points is generated and output to the image generation unit 14.

  The image generation unit 14 generates an ultrasonic image using the B-mode image data, Doppler image data, and the like output from the data processing unit 13. The image generation unit 14 includes a DSC (Digital Scan Converter), performs scan conversion of the generated image data, and generates an ultrasonic image (B-mode image or Doppler image) that can be displayed on the monitor 21.

  The image generation unit 14 generates a three-dimensional image (for example, an MPR image) from the volume data of other modalities stored in the storage unit 17 under the control of the control unit 16.

  The image generation unit 14 includes an image memory 15, stores image data such as a contrast image and a tissue image generated by the image generation unit 14 in the image memory 15, and stores image data read from the image memory 15 in the monitor 21. Output is enabled. Further, the image memory 15 stores three-dimensional image (for example, MPR image) data of other modalities generated by the image generation unit 14.

  Furthermore, the image memory 15 stores an output signal (Radio Frequency) immediately after passing through the transmission / reception unit 12, an image luminance signal, various raw data, image data acquired via the network 200, and the like as necessary. Even if the data format of the image data stored in the image memory 15 is the data format after the video format conversion displayed on the monitor 13, the coordinates are Raw data generated by the B-mode processing unit 131 and the Doppler processing unit 132. The data format before conversion may be used.

 The control unit 16 controls the entire ultrasound diagnostic apparatus 10 and executes various processes. For example, based on various setting requests input from the input unit 19 and various control programs and various setting information read from the storage unit 17, the transmission / reception unit 12, the B-mode processing unit 131, the Doppler processing unit 132, and the image generation unit 14. Control the processing. In addition, control is performed such that the ultrasonic image stored in the image memory 15 is displayed on the monitor 21. In addition, the control unit 16 uses, for example, three-dimensional image data of another medical image diagnostic apparatus 202 (for example, an X-ray CT apparatus, an MRI apparatus, etc.) according to the DICOM (Digital Imaging and Communications in Medicine) standard as a network. 200 is transmitted and received.

 Further, the control unit 16 aligns an arbitrary cross-section of the three-dimensional image data generated by the medical image diagnostic apparatus 202 with a cross-section scanned by the ultrasonic probe, and the three-dimensional image data and the three-dimensional space. Associate with. Details of the association between the three-dimensional image data and the three-dimensional space will be described later.

  The storage unit 17 stores various data such as a control program for performing ultrasonic transmission / reception, image processing, and display processing, diagnostic information (for example, subject ID, doctor's findings, etc.), and a diagnostic protocol. Furthermore, the storage unit 17 is also used for storing images stored in the image memory 15 as necessary. The storage unit 17 also stores volume data acquired by another medical image diagnostic apparatus 202 acquired by the control of the control unit 16. In addition, the storage unit 17 stores various types of information used for processing by the control unit 16.

  The interface unit 18 is an interface that controls the exchange of various types of information between the input unit 19, the position information acquisition unit 20, the network 200, and the main body 100. The input unit 19 includes input devices such as various switches, a keyboard, a trackball, a mouse, and a touch command screen, receives various setting requests from an operator, and transfers the various setting requests to the main body 100. For example, the input unit 19 accepts various operations related to alignment between an ultrasound image and an X-ray CT image.

  For example, the position information acquisition unit 20 acquires position information indicating where the ultrasonic probe 11 is located. As the position information acquisition device 20, for example, a magnetic sensor, an infrared sensor, an optical sensor, a camera, or the like is used. In the following description, an example using a magnetic sensor will be described.

  The monitor 21 displays a GUI (Graphical User Interface) for the operator of the ultrasound diagnostic apparatus 10 to input various setting requests by operating the input unit 19, or the ultrasound image generated in the main body 100 and the X Line CT images etc. are displayed in parallel.

  Next, the position information acquisition unit 20 of the ultrasonic diagnostic apparatus 10 according to an embodiment will be described. In the present embodiment, when the subject is scanned by the ultrasonic probe 11, a CT image or MRI image in which a lesion is detected is displayed as a reference image, and the position of the scanned cross section and the position of the reference image is the same. In order to match, a position information acquisition unit 20 is provided.

  FIG. 2 is an explanatory diagram schematically showing the arrangement of position sensors in the position information acquisition unit 20. That is, the position sensor system of FIG. 2 includes a transmitter 31 (transmitter) and a plurality of position sensors (receivers) 32, 33, 34. The transmitter 31 is, for example, a magnetic transmitter, is attached to a pole 38 or the like at a fixed position, and transmits a reference signal. The transmitter 31 forms a magnetic field outward from the device itself. Further, the three-dimensional magnetic field formed by the transmitter 31 is provided with position sensors 32, 33, and 34 made of, for example, magnetic sensors in an area where the magnetism transmitted from the transmitter 31 can be received.

  The position sensor 32 is attached to the ultrasonic probe 11 and receives the reference signal from the transmitter 31 to acquire position information in the three-dimensional space and detect the position and posture (tilt) of the ultrasonic probe 11. . The position sensor 33 is attached to a fixed position, for example, a predetermined position of the bed 39, and acquires position information in a three-dimensional space by receiving a reference signal from the transmitter 31. Further, when the transmitter 31 moves, its position (moving direction and moving amount) is detected. Furthermore, the position sensor 34 is attached to the subject P, and detects the position (body movement) of the subject P.

  The position information acquisition unit 20 acquires the position information of each sensor 32, 33, 34 on the basis of the position of the transmitter 31 and supplies it to the control unit 16 via the interface unit 18. When the control unit 16 scans the subject with the ultrasonic probe 11, the position of an arbitrary cross-section in the three-dimensional image data generated by the medical image diagnostic apparatus 202 and the cross-section scanned by the ultrasonic probe. The three-dimensional image data and the three-dimensional space are associated with each other. That is, the control unit 16 configures an association unit that associates the three-dimensional image data with the three-dimensional space.

  For example, by attaching the position sensor 32 to the probe 11, based on the detection result of the position sensor 32, at which position and angle of the subject P the currently displayed ultrasonic image (2D image) is acquired. Calculate At this time, the transmitter 31 serves as a reference for the position / angle information (the origin of the coordinate system). The volume data of the CT image or MRI image is read into the ultrasonic diagnostic apparatus 10 and the MPR image is displayed.

  Then, the MPR image and the ultrasonic image are displayed on the same screen, and the registration is performed by registering the position and angle information on the assumption that both images are currently displaying the same position. Thereby, thereafter, the same cross section as the ultrasonic image that changes with the movement of the probe 11 can be displayed as an MPR image. Therefore, a tumor or the like that is difficult to confirm with an ultrasound image can be confirmed with an MPR image, and puncture, RFA treatment, or the like can be performed under the guide of the ultrasound image.

  FIG. 3 shows a reference image (a) and an ultrasonic image (b) after alignment. As the reference image (a), for example, an MPR image (Multi Planer Reconstruction image) generated from volume data collected by an X-ray CT apparatus is used. As a reference image, an image acquired by an MRI apparatus can be used. In the following description, an example using a CT image will be described.

  FIG. 4 is an explanatory diagram illustrating an operation of aligning images when performing an ultrasonic diagnosis using a CT image (MPR image) as a reference image. 4A schematically shows the positional relationship between the transmitter 31 and each of the sensors 32, 33, and 34. FIG. 4B shows the transmit 31. FIG. 4C shows an MPR image generated from CT volume data. (D) shows an ultrasonic image scanned by the ultrasonic probe 11.

  As shown in FIG. 4, the volume data collected by the X-ray CT apparatus and the ultrasound image are associated using the magnetic sensor 32 attached to the ultrasound probe 11. That is, based on the detection result of the magnetic sensor 32 in the three-dimensional magnetic field formed by the transmitter 31, the three axes (X, Y, Z) of the ultrasonic probe 11 and the three axes of the volume data are aligned. Is called. For example, when the ultrasonic probe 11 to which the magnetic sensor 32 is attached is perpendicular to the subject and the set button is pressed in this state, the orientation of the magnetic sensor 32 at that time is set as vertical.

  Next, the ultrasonic probe 11 is moved so that the same characteristic part as the characteristic part drawn on the MPR image is drawn on the ultrasonic image, and the set button is pressed again. Thereby, the position (coordinates) of the magnetic sensor at that time is associated with the position (coordinates) in the volume data. As the characteristic portion, for example, a blood vessel or a xiphoid process is used.

  Then, by associating the direction and coordinates of the magnetic sensor 32 with the coordinates of the volume data, a two-dimensional image at the same position as the current scanning plane of the ultrasonic probe 11 can be generated from the volume data of other modalities. For example, as shown in FIGS. 4C and 4D, an ultrasonic image (right image) that changes as the ultrasonic probe moves and an MPR image (left image) of the same cross section are displayed. Is possible.

  Furthermore, by drawing and registering a feature portion detected in the MPR image, for example, a lesion that is suspected of cancer as a tumor range (ROI) on the MPR image, the feature portion is displayed on the ultrasound image at substantially the same position. A mark 36 indicating coordinates can be given. Alternatively, by drawing the ROI on the ultrasonic image, the mark 37 can be given at substantially the same position in the MPR image. The doctor can perform puncture based on the marks given to both images while comparing the ultrasonic image and the MPR image having different characteristics on the images.

  By the way, since the alignment using the position sensor 32 is based on the premise that the transmitter 31 does not move, if the transmitter 31 moves, accurate alignment cannot be performed. In addition, when the subject P moves, accurate alignment cannot be performed. Therefore, a position sensor 33 is attached to the fixed position, and a position sensor 34 for detecting body movement is provided.

  FIG. 5 is a block diagram illustrating a specific example of the ultrasonic diagnostic apparatus 10 according to an embodiment. In FIG. 5, the structure of the peripheral part relevant to the position information acquisition part 20 including the transmitter 31 and the position sensors 32, 33, 34 is shown.

  In FIG. 5, B-mode image data or Doppler mode image data obtained via the ultrasonic probe 11, the transmission / reception unit 12, and the data processing unit 13 is supplied to the ultrasonic image generation unit 141. The ultrasonic image generation unit 141 is included in the image generation unit 14 of FIG. The ultrasonic image generation unit 141 generates a 2D ultrasonic image and outputs it to the monitor 21.

  In addition, the position information acquisition unit 20 includes a sensor control unit 35 that communicates with the transmitter 31 and the position sensors 32, 33, and 34. Based on the signals received from the position sensors 32, 33, and 34, the sensor control unit 35 calculates the coordinates and orientations of the position sensors 32, 33, and 34 in the space with the transmitter 31 as the origin, and the calculated coordinates and orientations. Information is supplied to the position calculators 42, 43 and 44.

  The position calculation unit 42 calculates the position and inclination of the position sensor 32 attached to the ultrasonic pro unit 11. The position calculation unit 43 calculates the position of the position sensor 33, and calculates the position and direction when the position of the transmitter 31 changes. The position calculation unit 44 detects the body movement of the subject.

  The transmitter position correction unit 45 corrects the position information of the transmitter 31 based on the calculation result of the position calculation unit 43. The correction data from the transmitter position correction unit 45 is supplied to the position calculation unit 42 and the position calculation unit 44, respectively, and the position of the ultrasonic probe 11 and the position of the subject (body movement) when the position of the transmitter 31 is shifted. ) Is corrected. The output of the position calculation unit 44 is connected to the body motion correction calculation unit 46, and corrects the position of the ultrasonic probe 11 when the subject P moves. The output of the position calculation unit 42 is supplied to the alignment control unit 41. In addition, a pointing device 47 is provided to calibrate the coordinates of the feature portion using a trackball or the like.

  The DICOM data storage unit 201 corresponds to the medical server 201 or the storage unit 17 in FIG. 1 and stores CT images and MRI images acquired by the medical image diagnostic apparatus 202 (X-ray CT apparatus or MRI apparatus). The DICOM data read control unit 51 reads CT image data serving as a reference image from the DICOM data storage unit 201 and supplies the CT image data to the MPR image position calculation unit 52. The MPR image position calculation unit 52 calculates the position of an MPR image suitable as a reference image based on the alignment information from the alignment control unit 41. The MPR image generation unit 53 generates an MPR image corresponding to the position calculated by the MPR image position calculation unit 52 and outputs the MPR image to the monitor 21.

  An alignment control unit 41, position calculation units 42, 43, and 44, a transmitter position correction unit 45, and a body motion correction calculation unit 46 are included in the control unit 16 of FIG. 1, and include a DICOM data reading control unit 51, an MPR image position calculation. The unit 52 and the MPR image generation unit 53 are included in the image generation unit 14. The alignment control unit 41 and the MPR image position calculation unit 52 determine the positions of the cross section of the three-dimensional image data and the cross section scanned by the ultrasonic probe 11 based on the movement amount of the transmitter 31 and the movement amount of the subject P. A correction unit that corrects the deviation is configured.

  In FIG. 5, the position of the position sensor 33 does not change unless the transmitter 31 moves. Therefore, if the position and angle detected by the fixed sensor 33 change, it means that the position of the transmitter 31 has changed. Therefore, the position information of the position sensor 33 is monitored, and if the position information changes by a predetermined threshold value or more, a new coordinate system of the transmitter 31 is defined based on the original coordinate system based on the amount of movement. The reason why the threshold is provided is that when the position sensor 33 is a magnetic sensor, the position information that can be acquired fluctuates. Therefore, when the set threshold is exceeded, it is determined that the position of the transmitter 31 has changed.

  Here, as a correction method for alignment, the position information based on the new coordinate system of the transmitter 31 may be converted into the original coordinate system so that the Registration information can be used as it is (first correction process), The position / angle information defined in the coordinate system may be redefined in the new coordinate system, and the position / angle information may be re-registered as Registration information (second correction process).

  The position sensor 33 needs to be arranged in the magnetic field region of the transmitter 31. However, when a magnetic sensor is used as the position sensor 33, the position information cannot be obtained correctly due to distortion if placed near a metal or the like. It is necessary to avoid fixing it to the pole of the bed.

  Hereinafter, the first correction process of the ultrasonic diagnostic apparatus 10 in FIG. 5 will be described with reference to FIGS. 6 and 7. In the following description, for convenience, the position sensor 32 is called a probe sensor, the position sensor 33 is called a fixed sensor, and the position sensor 34 is called a body motion sensor. First, it is assumed that the position of the body motion sensor 34 is not changed.

  6, assuming that the ultrasonic probe 11 is not moved from the aligned state, the center coordinates (X1 ′, Y1 ′) of the MPR image of FIG. 6A1 and the superordinate of FIG. 6C1 are assumed. The center coordinates (X0, Y0) of the sound wave image are aligned.

At this time, as shown in FIG. 6B1, the coordinates of the position of the probe sensor 32 calculated by the position calculation unit 42 are (X1, Y1). The fixed sensor 33 is fixed in the magnetic field of the transmitter 31, and the coordinates of the position of the fixed sensor 33 calculated by the position calculation unit 44 are (X3, Y3). Further, the coordinates of the position of the body motion sensor 34 calculated by the position calculation unit 43 are (X5, Y5). Information on each coordinate is stored in the storage unit 17.

  On the other hand, when the transmitter 31 moves after the alignment, the three-dimensional space of the magnetic field formed by the transmitter 31 is shifted, so that the coordinates of the positions of the probe sensor 32, the fixed sensor 33, and the body motion sensor 34 are shifted. Changes. For example, as shown in FIG. 6 (b2), the position of the probe sensor 32 moves to the coordinates (X2, Y2), the position of the fixed sensor moves to the coordinates (X4, Y4), and the position of the body motion sensor changes to the coordinates. Move to (X6, Y6).

  At this time, the position calculation unit 43 acquires the coordinates (X4, Y4) of the fixed sensor 33 and calculates the amount of change from the initial coordinates (X3, Y3) stored in the storage unit 17. Here, when the calculated amount of change exceeds a predetermined threshold, the position calculation unit 43 determines that the position of the transmitter 31 has changed.

Then, the transmitter position correction unit 45 generates a conversion coefficient “M1” for converting the coordinates (X4, Y4) of the fixed sensor 33 into the initial coordinates (X3, Y3), and the probe sensor calculated by the position calculation unit 42 The coordinates of the probe sensor 32 are converted to (X1, Y1) by multiplying the coordinates (X2, Y2) of 32 by the conversion coefficient “M ₁ ”. Thereby, the coordinates of the probe sensor 32 acquired after the position of the transmitter 31 is changed can be returned to the coordinates before the position of the transmitter 31 is changed.

  Similarly, the coordinates of the body motion sensor 34 are converted to (X5, Y5) by multiplying the coordinates (X6, Y6) of the body motion sensor 34 calculated by the position calculation unit 44 by the conversion coefficient M1. Thereby, the coordinates of the body motion sensor 34 acquired after the position of the transmitter 31 is changed can be returned to the coordinates before the position of the transmitter 31 is changed.

  The alignment control unit 41 controls the MPR image position calculation unit 52 based on the result of coordinate conversion by the position calculation unit 42. Since the coordinates of the probe sensor 32 change when the position of the transmitter 31 changes, the MPR image position calculation unit 52 operates so as to change the cross-sectional position of the MPR image accordingly. However, since the coordinates of the probe sensor 32 are returned to the initial coordinates as a result of the coordinate conversion by the position calculation unit 42, the cross-sectional position of the MPR image is recalculated accordingly.

  The MPR image generation unit 53 generates an MPR image at the cross-sectional position calculated by the MPR image position calculation unit 52 based on the volume data, and outputs the MPR image to the monitor 21. Therefore, when the ultrasonic image (c2) from the ultrasonic image generation unit 41 is displayed on the monitor 21, the MPR image (a2) at substantially the same position as the scanning surface by the ultrasonic probe 11 can be displayed. Further, when the transmitter 31 is intentionally moved, the calculation can be performed similarly.

  Next, an operation when the body motion sensor 34 changes, that is, when the subject P moves will be described with reference to FIG.

  7, assuming that the ultrasonic probe 11 is not moved from the aligned state, the center coordinates (X1 ′, Y1 ′) of the MPR image of FIG. 7A1 and the superordinate of FIG. The center coordinates (X0, Y0) of the sound wave image are aligned.

At this time, as shown in FIG. 7B1, the coordinates of the position of the probe sensor 32 calculated by the position calculation unit 42 are (X1, Y1). The coordinates of the position of the fixed sensor 33 calculated by the position calculation unit 43 are (X3, Y3). Further, the coordinates of the position of the body motion sensor 34 calculated by the position calculation unit 44 are (X5, Y5). Information on each coordinate is stored in the storage unit 17.

  On the other hand, after the alignment, when the subject P moves and the position of the body motion sensor 34 changes, the coordinates of the position of the body motion sensor 34 change. Naturally, the position of the ultrasonic probe 11 also changes. For example, as shown in FIG. 7 (b2), it is assumed that the position of the body motion sensor has moved to coordinates (X8, Y8) and the coordinate of the probe sensor 32 has moved to (X7, Y7).

  At this time, the position calculation unit 43 acquires the coordinates (X8, Y8) of the body motion sensor 34 and calculates the amount of change from the initial coordinates (X5, Y5) stored in the storage unit 17. Here, when the calculated amount of change exceeds a predetermined threshold, the body motion correction calculation unit 46 determines that the subject P has moved.

  The body motion correction calculation unit 46 generates a conversion coefficient “N1” for converting the coordinates (X8, Y8) to the initial coordinates (X5, Y5), and the coordinates of the probe sensor 32 calculated by the position calculation unit 42 By multiplying (X7, Y7) by the conversion coefficient “N1”, the coordinates of the probe sensor 32 are converted to (X1, Y1). Thereby, the coordinates of the probe sensor 32 acquired after the subject P moves can be returned to the coordinates before the subject P moves. The coordinates (X3, Y3) of the fixed sensor 33 calculated by the position calculation unit 43 do not need to be converted.

  The alignment control unit 41 controls the MPR image position calculation unit 52 based on the result of the coordinate conversion by the position calculation unit 42 (conversion coefficient N1). When the position of the body motion sensor 34 changes, the coordinates of the probe sensor 32 also change, so that the MPR image position calculation unit 52 operates so as to change the cross-sectional position of the MPR image accordingly. However, since the coordinates of the probe sensor 32 are returned to the initial coordinates as a result of the coordinate conversion by the position calculation unit 42, the cross-sectional position of the MPR image is recalculated accordingly.

  The MPR image generation unit 53 generates an MPR image at the cross-sectional position calculated by the MPR image position calculation unit 52 based on the volume data, and outputs the MPR image to the monitor 21. Therefore, when the ultrasonic image (c2) from the ultrasonic image generation unit 41 is displayed on the monitor 21, the MPR image (a2) at substantially the same position as the scanning surface by the ultrasonic probe 11 can be displayed.

  When the subject P moves and the position of the transmitter 31 changes, the position calculation unit 42 performs coordinate conversion using both the conversion coefficient N1 and the conversion coefficient M1.

  FIG. 8 is an explanatory diagram showing a second correction process of the ultrasonic diagnostic apparatus of FIG.

  In the second correction process, as in FIG. 6, it is determined that the position of the transmitter 31 has changed when the amount of change in the coordinates of the fixed sensor 33 exceeds the threshold value. For example, as shown in FIG. 8 (a1), the coordinates (X1, Y1) of the probe sensor 32 in the space formed by the transmitter 31 and the coordinates (X1 ′, Y1 ′) of the MPR image are aligned, It is assumed that the coordinates (X3, Y3) of the fixed sensor 33 are acquired.

  Here, when the position of the transmitter 31 changes, the transmitter position correction unit 43 converts the initial coordinates (X3, Y3) of the fixed sensor 33 into coordinates (X4, Y4) as shown in (b2) of FIG. The conversion coefficient “M2” is created, and the coordinates (X2, Y2) are calculated by multiplying the coordinates (X1, Y1) of the probe sensor 32 by the conversion coefficient “M2”. The coordinates (X6, Y6) are calculated by multiplying the coordinates (X5, Y5) of the body motion sensor 34 by the conversion coefficient “M2”.

  Further, the alignment control unit 41 aligns the calculated coordinates (X2, Y2) with the MPR image coordinates (X1 ', Y1') again. Thereby, the coordinates in the magnetic field after the position of the transmitter 31 is changed and the MPR image of the volume data can be associated again. That is, in the second correction process, it is not necessary to perform the correction process every time the coordinates of the probe sensor 32 are acquired, and an increase in processing load can be suppressed.

  FIG. 9 is a flowchart showing an operation procedure of the ultrasonic diagnostic apparatus 10 according to the first embodiment. In step S1 of FIG. 9, it is determined whether or not the coordinates of the volume data and the coordinates of the ultrasonic image are aligned. After the alignment, in step S 2, the position information (coordinates in the magnetic field) of the fixed sensor 33 is acquired and stored in the storage unit 17.

  The acquisition timing of the position information in the fixed sensor 33 can be arbitrarily set. For example, when the scan is executed, the position information of the fixed sensor 32 may be always acquired. . Alternatively, when the freeze button is pressed, the acquisition of the position information may be interrupted, and the position information may be acquired when the freeze is released. Further, a correction mode on / off button may be provided in the input unit 19 so that position information may be acquired when the operator operates the correction mode on button.

  In step S3, it is determined whether or not the transmitter 31 has moved based on the position information acquired by the fixed sensor 33. When the position information of the fixed sensor 33 is acquired at the timing described above, the position calculation unit 43 determines that the transmitter 31 has moved when the amount of change from the initial coordinate information exceeds the threshold value. If the position calculation unit 43 determines that the transmitter 31 has moved, the position calculation unit 43 calculates the amount of change in the coordinates of the fixed sensor 33 in step S4. In step S <b> 5, the transmitter position correction unit 45 multiplies the position calculation unit 42 by the coordinate conversion coefficient M <b> 1, and the position of the ultrasonic probe 11, i.e., the probe sensor, based on the coordinate change amount of the fixed sensor 33. The coordinates acquired by 32 are corrected.

  In step S3, when it is determined that the transmitter 31 has not moved, it is determined whether the transmitter 31 has continuously moved based on the amount of change in the coordinates of the fixed sensor 33.

  In step S6, it is determined whether or not the subject P has moved based on the position information acquired by the body motion sensor 34. The position calculation unit 44 determines that the subject P has moved when the amount of change from the initial coordinate information exceeds a threshold value. Further, the position calculation unit 44 calculates the amount of change in the coordinates of the body motion sensor 34 in step S7. In step S <b> 8, the body motion correction unit 46 multiplies the position calculation unit 42 by the coordinate conversion coefficient N <b> 1 and corrects the coordinates acquired by the probe sensor 32 based on the amount of change in the coordinates of the body motion sensor 34. To do.

  If it is determined in step S6 that the subject P has not moved, it is determined whether the subject P has continuously moved based on the amount of change in the coordinates of the body motion sensor 34.

  Moreover, although the case where the 1st correction process (FIG. 6, FIG. 7) is performed is shown in the procedure of the process mentioned above, when the 2nd correction process (FIG. 8) is performed, step S5 is performed. Then, based on the amount of change in the position of the fixed sensor 33, the coordinates of the MPR image of the volume data and the corrected coordinates of the probe sensor 32 are associated again to perform alignment.

  As described above, according to the first embodiment, a change in the position of the transmitter 31 can be detected by detecting a change in the coordinates of the fixed sensor 33. Further, the transmitter 31 converts the coordinate of the probe sensor 32 based on the change amount of the coordinate of the fixed sensor 33 to correct the positional deviation between the cross section of the medical image and the cross section scanned by the ultrasonic probe 11. It is not necessary to align each time it moves, and the efficiency of diagnosis performed while referring to the reference image can be improved.

(Second Embodiment)
Although the first embodiment has been described above, various different embodiments can be employed in addition to the first embodiment described above. Hereinafter, the second embodiment will be described.

(1) Method for Detecting Change in Transmitter Position In the first embodiment, an example has been described in which the movement of the transmitter 31 is detected by detecting that the position of the fixed sensor 33 has changed beyond a threshold. The movement of the arm 38 for fixing the transmitter 31 may be mechanically measured to detect that the transmitter 31 has moved.
For example, a gear is arranged in the movable range of the arm 38 that fixes the transmitter 31, a detection device that detects how much the gear has moved is set, and when the arm 38 moves, the movement of the gear is detected by the detection device and detected. The detected movement of the gear is detected as a change in the position of the transmitter 31.
Further, a change in the position of the transmitter 31 may be detected by an image processing apparatus using a camera. In this case, the ultrasonic diagnostic apparatus 10 captures the transmitter 31 and a target at a fixed position with a camera. Then, the relative positional relationship between the transmitter 31 and the target is specified from the image captured by the camera by pattern matching for image recognition, and the transmitter 31 is changed according to the change in the correspondence (for example, distance) between the target and the target. A change in the position of 31 is detected.

(2) Position sensor In the first embodiment, the example in which the position sensors 32, 33, and 34 made of magnetic sensors are arranged in the three-dimensional magnetic field formed by the transmitter 31 is described. However, an infrared sensor can also be used. . In this case, infrared rays are emitted from the transmitter 31, and the position sensors 32, 33, and 34 are constituted by sensors that detect infrared rays. Further, as the transmitter 31 and the position sensors 32, 33, 34, a gyro sensor, GPS, or the like can be used.
In the first embodiment, the example in which only one fixed sensor 33 is arranged has been described. However, a plurality of fixed sensors 33 may be provided. When a plurality of fixed sensors are provided, an average value of position information of the plurality of fixed sensors is obtained, and the positional deviation is corrected based on the coordinates indicated by the average value. Alternatively, the sensor information with the highest accuracy among the plurality of fixed sensors may be preferentially adopted.

(3) Display of warning message The control unit 16 may display a message on the monitor 21 when it is determined that the position of the transmitter 31 or the subject P has changed. For example, the monitor 21 is warned such as “the transmitter has moved” or “the subject has moved”. Further, when the positional deviation is corrected, a message such as “corrected positional deviation due to movement of the transmitter” may be displayed on the monitor 21.

  According to the ultrasonic diagnostic apparatus of at least one embodiment described above, even when the transmitter or the subject moves, the positional deviation between the cross section of the reference image and the cross section scanned by the ultrasonic probe 11 is corrected. Therefore, alignment can be eliminated, diagnostic efficiency can be improved, and accurate inspection can be performed.

  As mentioned above, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 10 ... Ultrasound diagnostic apparatus 11 ... Ultrasonic probe 12 ... Transmission / reception part 13 ... Data processing part 14 ... Image generation part 15 ... Image memory 16 ... Control part 17 ... Memory | storage part 18 ... Interface part 19 ... Input part 20 ... Acquisition of positional information Part 21 ... Monitor (display part)
22 ... Bus line 31 ... Transmitter 32, 33, 34 ... Position sensor 41 ... Positioning control unit 42, 43, 44 ... Position calculation unit 45 ... Transmitter position correction unit 46 ... Body motion correction calculation unit 52 ... MPR image position calculation unit 53 ... MPR image generation unit 100 ... ultrasonic diagnostic apparatus 200 ... network 202 ... medical image diagnostic apparatus

Claims (10)

A transmitter for transmitting a reference signal in a three-dimensional space; a first sensor attached to an ultrasonic probe; a second sensor attached to a fixed position; and a third sensor attached to a subject; And a position information acquisition unit that acquires position information of each sensor in the three-dimensional space;
Based on the three-dimensional image data generated by the medical image diagnostic apparatus and the position information of the ultrasonic probe acquired by the first sensor, an arbitrary cross section of the three-dimensional image data and the ultrasonic probe are scanned. And an associating unit that associates the three-dimensional image data with the three-dimensional space;
A first position calculation unit that detects a change in the position of the transmitter based on position information acquired by the second sensor and calculates a movement amount of the transmitter;
A second position calculation unit that detects that the subject has moved based on the position information acquired by the third sensor and calculates a movement amount of the subject;
A correction unit that corrects a positional deviation between a cross section of the three-dimensional image data and a cross section scanned by the ultrasonic probe based on the movement amount of the transmitter and the movement amount of the subject;
A display unit for displaying an image based on the three-dimensional data and an ultrasonic image scanned by the ultrasonic probe;
An ultrasonic diagnostic apparatus comprising:   The correction unit generates a conversion coefficient for returning the coordinates after the change of the transmitter to the coordinates before the change based on the movement amount of the transmitter calculated by the first position calculation unit, The coordinates of the position of the probe calculated by the first sensor and the coordinates of the position of the subject calculated by the third sensor are converted according to the conversion coefficient, and the cross section of the three-dimensional image and the ultrasonic probe are used. The ultrasonic diagnostic apparatus according to claim 1, wherein a positional deviation from a scanned cross section is corrected. The associating unit redefines a new coordinate system after the change of the transmitter position based on the movement amount of the transmitter calculated by the first position calculating unit, and based on the new coordinate system And again aligning the cross section of the three-dimensional image data and the cross section scanned by the ultrasonic probe,
The correction unit converts the coordinates of the position of the probe calculated by the first sensor based on the new coordinate system of the transmitter, and scans the cross section of the three-dimensional image data and the ultrasonic probe. The ultrasonic diagnostic apparatus according to claim 1, wherein a positional deviation from a cross section to be corrected is corrected.   The first position calculation unit calculates a movement amount of the transmitter when the position of the transmitter changes to a preset threshold value or more based on position information acquired by the second sensor. An ultrasonic diagnostic apparatus according to 1.   The ultrasonic diagnostic apparatus according to claim 4, wherein a warning message is displayed on the display unit when a movement amount of the transmitter changes to the threshold value or more. A position information acquisition unit including a transmitter that transmits a reference signal in a three-dimensional space, a first sensor attached to the ultrasonic probe, a second sensor attached to a fixed position, and a third sensor attached to the subject. From the position information in the three-dimensional space where the respective sensors received the reference signal,
Based on the three-dimensional image data generated by the medical image diagnostic apparatus and the position information of the ultrasonic probe acquired by the first sensor, an arbitrary cross section of the three-dimensional image data and the ultrasonic probe are scanned. And aligning the three-dimensional image data with the three-dimensional space by the associating unit,
Based on the position information acquired by the second sensor, it detects that the position of the transmitter has changed and calculates the amount of movement of the transmitter,
Based on the position information acquired by the third sensor, the movement of the subject is calculated by detecting that the subject has moved,
Based on the amount of movement of the transmitter and the amount of movement of the subject, the positional deviation between the cross section of the three-dimensional image data and the cross section scanned by the ultrasonic probe is corrected,
An image data correction method for displaying an image based on the three-dimensional data and an ultrasonic image scanned by the ultrasonic probe on a display unit. The correction of the positional deviation is based on the amount of movement of the transmitter calculated by the first position calculator, and generates a conversion coefficient for returning the coordinate after the change of the transmitter to the coordinate before the change. ,
The coordinates of the position of the probe calculated by the first sensor and the coordinates of the position of the subject calculated by the third sensor are converted according to the conversion coefficient,
The image data correction method according to claim 6, wherein a positional deviation between a cross section of the three-dimensional image and a cross section scanned by the ultrasonic probe is corrected. The association unit redefines a new coordinate system after the position of the transmitter is changed based on the movement amount of the transmitter, and based on the new coordinate system, the cross-section of the three-dimensional image data Perform alignment with the cross section scanned by the ultrasonic probe again,
The correction of the positional deviation is performed by converting the coordinates of the position of the probe calculated by the first sensor based on the new coordinate system of the transmitter, and the cross section of the three-dimensional image data and the ultrasonic probe. The image data correction method according to claim 6, wherein a positional deviation from a cross section scanned by the correction is corrected.   The image data correction method according to claim 6, wherein the movement amount of the transmitter is calculated when the position of the transmitter changes to a preset threshold value or more based on position information acquired by the second sensor.   The image data correction method according to claim 9, wherein a warning message is displayed on the display unit when a movement amount of the transmitter changes to the threshold value or more.

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