JP5865664B2 - Medical image diagnostic apparatus and medical image processing method - Google Patents

Description

  Embodiments of the present invention relate to a medical image diagnostic apparatus and a medical image processing method for displaying ablation points in a time series on a fluoroscopic image when treating arrhythmia by ablation.

  In a conventional X-ray diagnostic apparatus (for example, an angiography apparatus), an X-ray generation unit that generates X-rays on a subject, and X-rays transmitted through the subject are two-dimensionally detected to generate X-ray projection data. An X-ray detection unit is provided. The X-ray generation unit and the X-ray detection unit are supported by an arm (generally called a C-arm), and the C-arm moves in the body axis direction of the subject on the bed or rotates around the body axis of the subject. Thus, the subject can be imaged from various directions.

  Conventionally, arrhythmia treatment by ablation is performed with an X-ray diagnostic apparatus. Ablation is a type of arrhythmia treatment, in which an ablation catheter is inserted into a blood vessel and carried into the heart. The signal is caused by the occurrence of arrhythmia, and the heart wall or pulmonary vein blood vessel that is the signal propagation path. On the other hand, by pressing the tip of the catheter for ablation and releasing high frequency energy, the tissue is cauterized (burned), and signals caused by arrhythmia cannot pass through the heart wall, thereby treating arrhythmia. is there.

  In recent arrhythmia treatment, the development of a three-dimensional potential mapping system such as CARTO has shortened treatment time and improved treatment results by catheter ablation. (Refer nonpatent literature 1).

  In particular, 90% of the signal generation sites that cause atrial fibrillation, a type of arrhythmia, are around the exit of the pulmonary vein to the left atrium, so that the arrhythmia signal does not propagate by cauterizing around the pulmonary vein exit. There are many treatments to make. In order to cauterize around the exit of the pulmonary vein, it is important to leave an image of the history of where the cautery was made.

  However, although ablation is actually progressing while confirming the catheter position, heart position, pulmonary vein exit, etc. on the fluoroscopic image, the ablation history cannot be left on the fluoroscopic image, and the position of the catheter There was a problem that they could not be recognized.

Tokyo Metropolitan Hiroo Hospital: Electro-anatomical mapping method (CARTO system) August 2002 <URL: http://www.byouin.metro.tokyo.jp/hiroo/5_electro.html>

The problem to be solved by the invention is to provide a medical image diagnostic apparatus and a medical image processing method for displaying ablated points on a fluoroscopic image in order to support arrhythmia treatment by ablation.

A medical image diagnostic apparatus according to an embodiment includes a support that supports an X-ray generation unit that emits X-rays to a subject, an X-ray detector that detects X-rays transmitted through the subject, and the subject A control unit that controls to rotate and move the support to see through the subject, and generates a fluoroscopic image based on the fluoroscopy , and the fluoroscopy in the ROI set on the fluoroscopic image display image to recognize the end position of the ablation catheter based on, an image processing unit that generates an image showing the ablation points corresponding to the ablation target position, an image showing the ablation point perspective image of said ROI And a display unit for displaying a LIH (Last Image Hold) image of a fluoroscopic image generated based on the fluoroscopy outside the ROI .

1 is a block diagram showing a configuration of a medical image diagnostic apparatus according to an embodiment. 1 is a perspective view showing an overall structure of a medical image diagnostic apparatus according to an embodiment. The figure explaining catheter ablation treatment roughly. The figure which shows the signal generation location which causes the atrial fibrillation which is a kind of arrhythmia. The flowchart which shows the process which displays the ablation point in the catheter for ablation on a fluoroscopic image. Explanatory drawing explaining the process of the flowchart of FIG. The flowchart which shows the process which displays the ablation point in the catheter for ablation in 2nd Embodiment on a fluoroscopic image. Explanatory drawing explaining the process of the flowchart of FIG.

  Hereinafter, a medical image 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.

  FIG. 1 is a block diagram illustrating a configuration of a medical image diagnostic apparatus according to an embodiment. The medical image diagnostic apparatus in FIG. 1 is an X-ray image diagnostic apparatus 100 called an angio apparatus, for example, and includes an X-ray generation unit 10 that generates X-rays with respect to the subject P, and an X-ray that has passed through the subject P. Are two-dimensionally detected, and an X-ray detection unit 20 that generates X-ray projection data based on the detection result is provided.

  The X-ray generation unit 10 includes an X-ray irradiation unit having an X-ray tube 11 and an X-ray diaphragm 12, a high voltage control unit 13, and a high voltage generator 14. The X-ray tube 11 is a vacuum tube that generates X-rays, and accelerates electrons emitted from a cathode (filament) by a high voltage to collide with a tungsten anode to generate X-rays. The high voltage control unit 13 controls the high voltage generator 14 according to an instruction signal from the system control unit 50 (described later), and the tube current of the X-ray tube 11, tube voltage, X-ray pulse width, irradiation period, imaging period, Control of X-ray irradiation conditions including irradiation time and the like is performed.

  The X-ray detector 20 includes a flat panel detector (FPD) 21, a charge / voltage converter 22 that converts charges read from the flat detector 21 into a voltage, and a charge / voltage converter 22. An A / D converter 23 that converts the output into a digital signal is provided, and X-ray projection data is output from the A / D converter 23.

  The X-ray generator 10 and the X-ray detector 20 are supported by an arm (C arm) 24. The C-arm 24 can move in the body axis direction of the subject P placed on the couch top 25 and can rotate around the body axis of the subject P. The X-ray generation unit 10 and the X-ray detection unit 20 constitute an imaging unit 26. By rotating the C-arm 24, the imaging unit 26 rotates around the subject P and is observed from a plurality of different angular directions. The specimen P can be photographed.

  The X-ray image diagnostic apparatus 100 includes an image processing unit 30. The image processing unit 30 processes the X-ray projection data from the A / D converter 23 to generate and store image data, and includes an image data storage unit 31 and a calculation unit 32. X-ray projection data is sequentially stored in the image data storage unit 31 to generate image data. In addition, the calculation unit 32 performs image processing and calculation for the purpose of contour enhancement and S / N improvement on the generated image data as necessary. Moreover, it has the ECG measurement part 33 which measures the biological signal of the subject P, for example, an ECG signal (electrocardiogram waveform), a heart sound waveform, a pulse wave and the like.

  The image data processed by the image processing unit 30 is read from the image data storage unit 31 and supplied to the display unit 35. The display unit 35 includes a display data generation unit 36, a conversion unit 37, and a monitor 38 in order to display image data. The display data generating unit 36 generates display data by synthesizing incidental information with image data or converting the image data into a predetermined display format. The conversion unit 37 performs D / A (digital / analog) conversion and television format conversion on the display data to generate a video signal, and displays the video signal on a monitor 38 such as a liquid crystal display.

  The image processing unit 30 is connected to the system control unit 50 via the bus line 39. The image data storage unit 31 and the calculation unit 32 process the image data under the control of the system control unit 50.

  The system control unit 50 includes a CPU and a storage circuit (not shown), and each of the X-ray image diagnostic apparatuses 100 via the bus line 39 based on input information, setting information, and selection information supplied from the operation unit 51. A control unit that controls the unit in an integrated manner is configured.

  The operation unit 51 is used by a user such as a doctor to input various commands, and has an interactive interface including a pointing device 52 such as a mouse, a trackball, and a joystick, a keyboard, a display panel, and various switches. In the following description, a mouse is used as an example of the pointing device 52. Further, the operation unit 50 sets the moving direction and moving speed of the top board 25, sets the rotation / moving direction and rotating / moving speed of the imaging system, sets the X-ray irradiation conditions including tube voltage and tube current, and the like. Do.

  Further, the X-ray image diagnostic apparatus 100 includes a moving mechanism unit 40. The movement mechanism unit 40 includes a diaphragm movement control unit 41 and a mechanism control unit 42. The diaphragm movement control unit 41 performs movement control of the diaphragm blades and the like in the X-ray diaphragm 12 and sets an ROI (Region of Interest). The mechanism control unit 42 controls the moving mechanism 43 of the top plate 25 on which the subject P is placed and the rotational moving mechanism 44 that rotates and moves the C arm. The movement mechanism unit 40 operates in response to the operation of the operation unit 51, and performs movement control of each unit under the control of the system control unit 50.

  FIG. 2 is a perspective view showing an overall configuration of the X-ray image diagnostic apparatus 100 (angio apparatus). In FIG. 2, the X-ray generation unit 10 and the X-ray detection unit 20 are supported by a C arm 24 so as to face each other. A couch is arranged with respect to the C arm 24, and a subject (not shown) is placed on the couch top 25. The position and height of the couch 25 can be controlled by the mechanism control unit 42. It is.

  The C arm 24 is supported by, for example, a rail provided on the ceiling, and is movable in the body axis direction from the head (Cranial) to the leg (Caudal) of the subject. The imaging unit 26 (the X-ray generation unit 10 and the X-ray detection unit 20) can rotate around the body axis around the body axis by the rotation of the C-arm 24. Further, the photographing unit 26 can be slid and rotated along the C arm 24.

  The X-ray projection data is processed by the image processing unit 30 and the image data is displayed on the monitor 38. The monitor 38 is attached to the ceiling, for example. An operation unit 511 is attached to the bed, and in response to the operation of the operation unit 511, the system control unit 50 controls the height of the top plate 25, controls the movement / rotation of the C arm 24, and controls the X-ray. Adjustment of irradiation range, control of irradiation timing, etc. are performed.

  FIG. 3 is a diagram schematically illustrating catheter ablation treatment. In FIG. 3, a high frequency generator 60 is provided, and an ablation catheter 61 is inserted from a blood vessel and carried into the heart when treating arrhythmia. In the case of atrial fibrillation, the ablation catheter 61 is carried to the left atrium, and the distal end of the ablation catheter is directed to the source of the signal causing arrhythmia and the heart wall or pulmonary vein blood vessel serving as the signal propagation path. Press down. As shown in the frame A of FIG. 3, the tissue is cauterized (burned) by releasing high-frequency energy from the electrode 62 provided at the distal end of the ablation catheter 61, and a signal caused by arrhythmia passes through the heart wall. Treat arrhythmias without getting through.

  As shown in FIG. 4, 90% of the signal generation locations that cause atrial fibrillation, which is a kind of arrhythmia, are around the outlet of the pulmonary vein to the left atrium (dotted line B) and cauterize around this pulmonary vein outlet. Thus, the arrhythmia signal is treated so as not to propagate.

  By the way, in order to cauterize around the exit of the pulmonary vein, it is important to leave a history of where the cautery has been left in an image. In the embodiment, ablation can be performed while confirming the position of the catheter, the position of the heart, the outlet of the pulmonary vein, and the like on the fluoroscopic image, and ablation history (ablation history) is left.

  Hereinafter, image processing by the image processing unit 30 will be described. The image processing unit 30 displays the ablation point on the ablation catheter on the fluoroscopic image, and performs processing according to the flowchart of FIG.

  In FIG. 5, in step S <b> 1, the photographing unit 26 performs fluoroscopy. When the fluoroscopy is finished, an LIH image is displayed on the monitor 38. That is, in the X-ray diagnostic imaging apparatus 100, “fluoroscopic” in which an X-ray image is obtained by irradiating an X-ray with a small dose, and image data is recorded by irradiating an X-ray with a large dose, and diagnosis is performed from the recorded image data There is "shooting" to get information. In addition, a fluoroscopic image obtained at the end of fluoroscopy may be displayed as a still image on a monitor. This still image is referred to as a LIH (Last Image Hold) image.

  In step S2, an ROI for performing partial imaging (perspective) is selected. Partial imaging (fluoroscopy) is ROI fluoroscopy. In step S3, an unnecessary area for X-ray exposure is covered with a diaphragm blade, and only a necessary area is irradiated with X-rays. In other words, after selecting the area on the image that you want to irradiate with X-rays, pressing a foot switch dedicated to partial imaging (perspective) will cause the diaphragm blades to enter the outside of the automatically set ROI, and only within the ROI. X-ray hits. In addition, the outside of the ROI has diaphragm blades and is a dark image, but the LIH image remains on the outside of the ROI.

  In step S4, the tissue is cauterized by releasing high frequency energy from the electrode 62 provided at the distal end of the ablation catheter 61. Further, the image data seen through the ROI is stored in the image data storage unit 31 for a plurality of frames.

  Next, in step S5, the tip of the ablation catheter is determined on each of the fluoroscopic frames. Originally, in ablation, many catheters such as a catheter for measuring electric potential and an ablation catheter are placed in the heart, and it is difficult to distinguish which is an ablation catheter under normal fluoroscopy. However, in reality, the distal end of the ablation catheter has a special shape and a small number of electrodes, which is advantageous.

  In addition, when performing partial imaging (fluoroscopy), basically, when ablation (cautery) is being performed and the X-ray irradiation area is limited within the ROI setting, recognition of the ablation catheter is performed. Easy to recognize and there are few recognition errors by software. Therefore, the tip of the ablation catheter is recognized from the tip shape learning and the number of electrodes.

  If the tip of the ablation catheter can be recognized, images of a plurality of frames irradiated with X-rays by partial imaging (perspective) are collected and stored in the image data storage unit 31, and the position of the tip of the ablation catheter in each frame is calculated. .

  Thereafter, in step S6, an ablation point is calculated by determining an average position of each position of the distal end of the ablation catheter in a plurality of frames. The ablation point is calculated based on images of a plurality of frames.

  In step S7, an image showing the calculated ablation point is generated and displayed on the fluoroscopic image. Thereafter, the ROI is set in the same manner, the distal end of the ablation catheter is moved to the next ablation point and cauterized, and image data seen through the ROI is stored in the image data storage unit 31 for a plurality of frames. Each ablation point is calculated and images of the ablation points are sequentially generated and displayed on the fluoroscopic image.

  Therefore, each ablation point can be displayed in time series on the fluoroscopic image, and the ablation history can be displayed. Ablation history display makes it difficult to leave ablation due to ablation and enables accurate ablation.

  In addition, it can select whether a shochu point is added to a display by a user's intention. The ablation point may be displayed not only on the perspective image but also on the reference image. The reference image is a fluoroscopic image in a state in which a contrast medium is administered, and is an image that is displayed next to a general fluoroscopic image, for example.

  FIG. 6 is an image example for explaining the processing of the flowchart of FIG. 5, and S <b> 1 to S <b> 7 are matched with the reference numerals of steps S <b> 1 to S <b> 7 of FIG. 5.

  (S1) in FIG. 6 shows an image (LIH image, reference image, or the like) displayed on the monitor after being seen through by the photographing unit 26. Here, an LIH image is shown. (S2) in FIG. 6 shows selection of ROI for performing partial photographing (perspective), and selects ROI from an image (LIH image or reference image) displayed on the monitor. The ROI is selected by controlling the diaphragm movement control unit 41, covering an unnecessary area for X-ray irradiation with diaphragm blades, and irradiating only the necessary area with X-rays. By selecting the ROI, the diaphragm blade enters the outside of the set ROI, and the X-ray hits only within the ROI. In FIG. 6 (S2), the outside of the ROI has a diaphragm blade and is a dark image, but the LIH image is left outside the ROI. That is, only the fluoroscopic image in the ROI is updated.

  Next, the tissue is cauterized by releasing high frequency energy from the electrode 62 provided at the distal end of the ablation catheter 61. The image data seen through the ROI is stored in the image data storage unit 31 for a plurality of frames, and the tip of the ablation catheter is determined on each seen through frame.

  In FIG. 6 (S5a), an image in the ROI is shown enlarged. In FIG. 6 (S5a), the distal end 62 of the ablation catheter 61 is recognized from features such as the distal end shape and the number of electrodes. The heart moves during fluoroscopy. For example, if it moves in the direction of arrow C, the tip 62 of the ablation catheter also moves as shown in FIG. 6 (S5b). Therefore, an average position of each position of the distal end of the ablation catheter in a plurality of frames is calculated. Further, the average position is set as the ablation point, and an image D1 indicating the ablation point is generated as shown in FIG. 6 (S6).

  In the same manner, the distal end of the ablation catheter is moved to the next ablation point and cauterized, and image data seen through the ROI is stored in the image data storage unit 31 for a plurality of frames, and each ablation point is displayed. D1, D2, D3... Are generated.

  Then, as shown in FIG. 6 (S7), images D1, D2, D3... Showing the ablation points are displayed in time series on the fluoroscopic image. Therefore, the ablation history can be displayed on the fluoroscopic image. FIG. 6 (S7a) is an enlarged view of the images D1, D2, D3... Showing the ablation points, and the ablation history can be displayed.

  In the first embodiment, the ablation point by the ablation catheter can be displayed on the fluoroscopic monitor in time series without involving human hands. As a result, the procedure can be advanced while recognizing the ablated place, and the ablation leakage can be reduced. That is, ablation treatment can be performed in a short time, and effects such as reduction of burden on doctors, technicians, nurses, patients, and reduction of exposure can be expected.

  Next, a second embodiment will be described. In the second embodiment, an image showing the ablation point is generated and displayed without recognizing the ablation catheter. In the second embodiment, a signal line 53 between the mouse 52 and the monitor 38 and a signal line 54 between the arithmetic unit 32 and the monitor 38 are added in FIG.

  In the second embodiment, where the tip of the ablation catheter is moved is instructed by the mouse 52 (pointing device), and the cauterization point is designated and cauterization is performed.

  FIG. 7 shows a flowchart when displaying the ablation point in the catheter for ablation on the fluoroscopic image in the second embodiment. In step S <b> 11 of FIG. 7, the photographing unit 26 performs fluoroscopy. When the fluoroscopy is finished, an LIH image is displayed on the monitor 38.

  In step S12, an ROI for performing partial imaging (perspective) is selected. That is, at the time of performing partial imaging (perspective), the pointer is moved on the LIH image using the mouse 52 to designate the tip position of the ablation catheter, and the spot area is set with this as the center of the ROI.

  The center of the selected spot area can be considered as the ablation center position (atrial fibrillation is a treatment of the left atrium, and the myocardium does not move significantly in the left atrium, so this idea can be applied). Accordingly, in step S13, the calculation unit 32 recognizes the position of the pointer as the center of the ROI and recognizes it as the distal end of the ablation catheter. The recognized position is stored in the image data storage unit 31.

  In step S14, an image showing the ablation point at the stored position is generated and displayed on the fluoroscopic image. Thereafter, the ablation history is displayed by sequentially moving the ablation point to recognize the distal end of the ablation catheter and displaying an image showing the ablation point at the recognized position in time series.

  FIG. 8A shows a state in which the ROI is selected, and the pointer E is moved using the mouse 52 to instruct the distal end of the ablation catheter to be at the center position of the ROI.

  FIG. 8B shows a state in which the position of the ROI is changed by shifting the position of the pointer E from E1 to E2. The system control unit 50 recognizes the center of the ROI, that is, the position of the pointer E as the distal end of the ablation catheter, and stores the position in the image data storage unit 31. Therefore, by sequentially changing the position of the pointer E with the mouse 52 and instructing the tip position of the ablation catheter, the images D1 and D2 showing the ablation points can be displayed on the fluoroscopic image.

  FIG. 8C shows a display example of the ablation history, and the images D1, D2, D3... Correspond to FIG. In addition, it can select whether a shochu point is added to a display by a user's intention. The ablation point may be displayed not only on the perspective image but also on the reference image.

  According to the second embodiment, ablation points (ablation history) can be displayed without recognizing the ablation catheter.

  As described above, according to the embodiment of the present invention, the ablation point by the ablation catheter can be displayed on the monitor in time series, and the procedure can be advanced while recognizing the ablated place. Moreover, ablation leakage can be reduced, and ablation treatment can be performed in a short time.

  In the above embodiment, the example in which the flat detector 21 is used in the X-ray detector 20 has been described. However, the X-ray I.D. I. An X-ray detection unit including (Image Intensifier) and an X-ray TV camera can also be used.

  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.

100 ... Medical diagnostic imaging apparatus (X-ray diagnostic imaging apparatus)
DESCRIPTION OF SYMBOLS 10 ... X-ray generation part 11 ... X-ray tube 20 ... X-ray detection part 21 ... Planar detector 24 ... C arm 25 ... Top plate 26 ... Imaging | photography part 30 ... Image processing part 31 ... Image data storage part 32 ... Calculation part 35 ... Display unit 39 ... Bus line 40 ... Movement mechanism unit 41 ... Aperture movement control unit 50 ... System control unit 51 ... Operation unit 52 ... Pointing device

Claims (6)

A support that supports an X-ray generator that irradiates the subject with X-rays and an X-ray detector that detects X-rays transmitted through the subject;
A control unit that controls to rotate and move the support relative to the subject to see through the subject;
Based on the fluoroscopy, a fluoroscopic image is generated , and the tip position of the ablation catheter is recognized based on the fluoroscopic image in the ROI set on the fluoroscopic image, and an ablation point corresponding to the ablation target position is indicated. An image processing unit for generating an image;
A display unit that displays an image showing the ablation point on the fluoroscopic image in the ROI, and displays a LIH (Last Image Hold) image of the fluoroscopic image generated based on the fluoroscopy outside the ROI ;
A medical image diagnostic apparatus comprising: Wherein the image processing unit calculates the average position of the tip of the ablation catheter contained in a fluoroscopic image of said ROI of a plurality of frames, the medical image diagnostic apparatus according to claim 1, wherein for generating an image indicative of the ablation points . A pointing device that indicates with a pointer where to move the tip of the ablation catheter, and indicates the center of the ROI set on the fluoroscopic image with the pointer;
The medical image diagnostic apparatus according to claim 1, wherein the image processing unit sequentially stores a position indicated by the pointer and generates an image indicating the ablation point at the stored position. Rotating and moving a support that supports an X-ray generation unit that emits X-rays to the subject and an X-ray detector that detects X-rays transmitted through the subject, and sees through the subject.
Based on the fluoroscopy, a fluoroscopic image is generated , and the tip position of the ablation catheter is recognized based on the fluoroscopic image in the ROI set on the fluoroscopic image, and an ablation point corresponding to the ablation target position is indicated. Generate an image ,
A medical image processing method for displaying an image showing the ablation point on a fluoroscopic image in the ROI and displaying a LIH (Last Image Hold) image of the fluoroscopic image generated based on the fluoroscopy outside the ROI . 5. The medical image processing method according to claim 4 , wherein an image indicating the ablation point is generated by calculating an average position of a tip image of the ablation catheter included in a fluoroscopic image of the ROI of a plurality of frames. Directs the center of the ROI set on the front Symbol fluoroscopic image by the pointer of the pointing device,
The medical image processing method according to claim 4 , wherein the position indicated by the pointer is sequentially stored, and an image indicating the ablation point is generated at the stored position.