JP5159299B2 - X-ray CT apparatus and medical image processing apparatus - Google Patents

Description

  The present invention relates to an X-ray CT apparatus and a medical image processing apparatus having a cardiac resynchronization therapy execution function for evaluating a synchronized state of heart motion.

  If the electrical conduction system of the heart is abnormal and the transmission of electrical signals is poor, the left ventricle may be delayed or may not move at all. In such a case, cardiac resynchronization therapy (Patent Document 1) is known as a method of activating movement by applying electrical stimulation to an abnormal portion of the left ventricle.

By the way, in the conventional cardiac resynchronization therapy, an ultrasonic diagnostic apparatus is used as a means for evaluating the synchronized state of the movement of the left ventricular wall (endocardium). In this method, ultrasonic waves are transmitted / received to / from the heart portion of the patient, and an image of the target portion is generated and displayed on the monitor.
Special table 2007-500550 gazette

  However, since the ultrasonic diagnostic apparatus used so far transmits and receives ultrasonic waves from the outside of the patient, the range in which the observation field is narrow and the synchronization state can be evaluated is limited, and an ultrasonic wave that transmits and receives ultrasonic waves is limited. Since there is a lack of anatomical information about the heart portion obtained from the mounting position of the acoustic probe, it is difficult to evaluate a synchronized state with high accuracy and stability. Furthermore, the target portion may not be visible depending on the skill level of the operator of the ultrasonic diagnostic apparatus, and there is a problem that the observation result is not reproducible and difficult to use.

  The present invention has been made in view of the above circumstances, and provides an X-ray CT apparatus and a medical image processing apparatus having a cardiac resynchronization therapy execution function capable of stably evaluating the synchronization state of heart motion. With the goal.

X-ray CT apparatus according to the present invention radiates X-rays to a subject, wherein the X-ray CT apparatus for obtaining image data by X-rays transmitted through the subject, at least one heartbeat of the heart than the previous SL image data A distance change amount from a predetermined position is calculated for each of a plurality of regions on the myocardial wall of the left ventricular lumen from image data of a plurality of volumes captured for the minute, and the periodic change of the distance change amount for each of the regions of being a deviation amount calculation means for calculating a phase shift amount, and a display image generating means for generating a parameter map or change the graph represents the displacement amount before Symbol phase, characterized by comprising a.

The medical image processing apparatus according to the present invention, the medical image processing apparatus that displays an image based on the medical image acquired by the X-ray CT apparatus, a plurality volumes to be taken for at least one heartbeat of the heart A shift for calculating the amount of change in distance from a predetermined position for each of a plurality of regions on the myocardial wall of the left ventricular lumen from the image data, and determining the amount of phase shift of the periodic change of the distance change for each of the regions is the amount calculating means, a display image generating means for generating a parameter map or change the graph represents the displacement amount before Symbol phase, characterized by comprising a.

  ADVANTAGE OF THE INVENTION According to this invention, the X-ray CT apparatus and medical image processing apparatus which have a cardiac resynchronization therapy execution function which can perform the evaluation of the synchronous state of a heart motion stably can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of an X-ray CT apparatus according to a first embodiment of the present invention.

  In this case, the X-ray CT apparatus includes a gantry device 10, a couch device 20, and a console unit 30. The gantry 10 includes a rotating gantry 11, and an X-ray source 12 and an X-ray detector 13 are arranged to face each other with the rotating gantry 11 interposed therebetween. Further, the gantry device 10 is provided with a high voltage generation unit 14, a gantry driving unit 15, an aperture driving unit 16, and a data collecting unit (DAS) 17.

  The rotary base 11 holds the X-ray source 12 and the X-ray detector 13, and is centered on a rotation axis located at the midpoint of a straight line connecting the X-ray source 12 and the X-ray detector 13 by the base drive unit 15. And rotated. The gantry driving unit 15 rotates the rotating gantry 11 based on a gantry control signal output by the control unit 31 described later.

  The high voltage generator 14 supplies a high voltage according to the imaging conditions to the X-ray source 12 based on a control signal from the controller 31. In this case, the X-ray source 12 exposes an X-ray beam such as a fan shape or a cone shape by the high voltage supplied from the high voltage generator 14. The aperture drive unit 16 moves the X-ray shielding plate according to the imaging conditions, and adjusts the exposure range in the X-ray slice direction.

  The X-ray detector 13 detects an X-ray beam that has been exposed from the X-ray source 12 and transmitted through the subject P, and outputs a detection signal. Here, when the X-ray CT apparatus is, for example, a single slice CT apparatus, the X-ray detector 13 is configured by arranging, for example, 1000 channels of X-ray detection elements in a row in a fan shape or a linear shape. In addition, these X-ray detection elements are configured as a unit that is grouped into a plurality of channels, for example, every 24 channels, and a plurality of these units are arranged.

  On the other hand, the couch device 20 has a couch top 21 on which the subject P is placed. The bed top 21 is supported by a bed base 22 having a bed driving unit 23.

  The couch driving unit 23 calculates the movement amount of the couch top 21 per rotation of the rotating gantry 11 based on the couch movement control signal output from the control unit 31, and the couch is calculated with the calculated movement amount at the time of scanning. The top plate 21 is moved. In this case, the bed top plate 21 is moved in the vertical direction by the bed driving unit 23 with the subject P placed thereon, and is movable in the body axis direction of the subject P.

  The console unit 30 has a control unit 31. The control unit 31 is connected to the above-described high voltage generation unit 14, gantry driving unit 15, aperture driving unit 16, data collection unit 17, and bed driving unit 23. In addition to the control unit 31, the console unit 30 includes a console I / F (interface) unit 32, a reconstruction processing unit 33, an image storage unit 34, an image processing unit 35, a display device 36, and an input unit 37. ing.

  The control unit 31 controls the entire apparatus. In this case, the control unit 31 outputs an X-ray beam generation control signal for controlling the X-ray beam generation to the high voltage generation unit 14, and instructs the gantry driving unit 15 to start diagnosis, and A gantry control signal for controlling the driving of the rotating gantry 11 is output. Further, the control unit 31 outputs a data acquisition control signal for controlling the data acquisition drive to the data acquisition unit 17, and outputs an aperture control signal for controlling the aperture of the X-ray beam to the aperture drive unit 16. Output. Then, a diagnosis start instruction and a bed movement control signal for controlling the bed movement are output to the bed driving unit 23.

  The console I / F unit 32 receives transmission data from the data collection unit 17 that has collected the detection signals of the X-ray detector 13 by the gantry device 10. The reconstruction processing unit 33 reconstructs an image for the subject P based on the collected data of the data collecting unit 17 input via the console I / F unit 32 and outputs the image data. The image storage unit 34 temporarily stores the tomographic image data reconstructed by the reconstruction processing unit 33. The image processing unit 35 generates CT image data from the data stored in the image storage unit 34 and causes the display device 36 to display the CT image data. Further, the image processing unit 35 has a cardiac resynchronization therapy execution function for evaluating the synchronization state of the heart motion. Details of the cardiac resynchronization therapy execution function in the image processing unit 35 will be described later. The input unit 37 inputs various imaging condition settings, an instruction to start cardiac resynchronization therapy, and the like.

  As shown in FIG. 2, the image processing unit 35 includes a shift amount calculation unit 351, a parameter map generation unit 352 that constitutes a display image generation unit, and a overlap display unit 353 as a cardiac resynchronization therapy execution function. Based on the image data stored in the image storage unit 34, the deviation amount calculation means 351 is a predetermined position in the left ventricular lumen of the heart, for example, the distance from the central axis (heart axis) of the myocardial motion to each region (position) of the myocardial wall. The amount of change in the time direction (heartbeat phase direction) is obtained, and the periodic change of this distance change amount, that is, the distance change amount is converted into a periodic function to obtain a periodic change, and an asynchronous region in which the period is shifted is detected, The deviation amount is calculated. The parameter map generation unit 352 generates, for example, a two-dimensional (or three-dimensional) parameter map that represents the amount of shift in the period in the non-periodic area detected by the non-periodic area detection unit 351. The overlapping display unit 353 displays the parameter map generated by the parameter map generation unit 352 on the overlay display device 36 on the three-dimensional image of the heart obtained from the CT image data.

  Next, the operation of the embodiment configured as described above will be described.

  First, various imaging conditions for cardiac examination are set by the input unit 37. In this state, when an X-ray beam generation control signal is output from the control unit 31 to the high voltage generation unit 14, X-rays are exposed from the X-ray source 12. The X-ray beam passes through the subject P and is detected by the X-ray detector 13. When detecting the X-ray beam, the X-ray detector 13 outputs a detection signal. This detection signal is collected by the data collection unit 17 and input to the reconfiguration processing unit 33 via the console I / F unit 32 of the console unit 30. The reconstruction processing unit 33 reconstructs an image of the subject P (here, a CT image of the heart) based on the collected data from the data collecting unit 17 and stores the image in the image storage unit 34.

  In this state, when an instruction to start cardiac resynchronization therapy is input from the input unit 37, the flowchart shown in FIG. 3 is executed.

  First, in step 301, the CT image data of the heart stored in the image storage unit 34 is taken into the deviation amount calculation unit 351 of the image processing unit 35 (first unit). In this case, CT image data captures a plurality of volumes (for example, 20 volumes or more) for at least one heartbeat. Next, in step 302, CT image data is displayed on the display device 36, and the left ventricle lumen 41 shown in FIG. 4A is detected. Then, the process proceeds to step 303 to detect the cardiac axis 42 which is the center of the myocardial movement in the left ventricular lumen 41 (second means). In step 304, the myocardial inner wall 43 is detected as a myocardial wall that serves as a measurement standard for the distance from the cardiac axis 42. In this case, the myocardial wall may be not the myocardial inner wall 43 but the outer wall of the left ventricular lumen 41 or an intermediate position between the inner wall and the outer wall.

  Next, proceeding to step 305, the left ventricular myocardium is normalized for each volume for one heartbeat. In this case, the myocardial inner wall 43 detected in step 304 is divided into a plurality of regions, and each region is associated with all volumes. In step 306, the distance from the cardiac axis 42 in each region (each left ventricular myocardial position) of the myocardial inner wall 43 associated (normalized) for all volumes is calculated.

  Next, the process proceeds to step 307. In step 307, for each region of the normalized myocardial inner wall 43, the distance change amount from the heart axis 42 for one heartbeat is plotted as a curve, for example, a distance change graph shown in FIG. 4B is created. . In this case, in FIG. 4B, the change graph a1 corresponds to the region b1 of the myocardial inner wall 43, the change graph a2 corresponds to the region b2 of the myocardial inner wall 43, and the change graph an similarly represents the myocardial inner wall 43. Corresponds to the region bn. In the above description, one heartbeat is used, but if there are a plurality of heartbeats, a change graph is created by averaging or approximating the plot results for each heartbeat.

  Next, in step 308, a curve (change graph) of the distance change amount from the central axis 42 is converted into a periodic function by Fourier transform or the like (third means). In step 309, a positive (or negative) peak is detected from the change amount periodic function. In this case, positive and negative peaks may be detected.

  Next, the process proceeds to step 310. In step 310, the time of the positive (or negative) peak detected in step 309 is set as the value of each region of the myocardial inner wall 43, and there is a significant difference between the values set in these regions. Is detected as a deviation. In this case, for the determination of the significant difference, for example, a relative value such as (heart rate × (1/20) msec) used as a criterion for determining myocardial abnormality in ultrasonic diagnosis or the like, Statistical standard deviation values that are statistically obtained from the entire regions are used as threshold values.

  Here, when the latter statistical standard deviation value is adopted, the most frequent period in each region of the myocardial inner wall 43 is, for example, the statistical standard deviation value “100”, and the deviation from the value (period) is different. A certain region is determined as an “unsynchronized (asynchronous)” region, and the phase (period) shift amount at this time is quantified (fourth means).

  Next, the process proceeds to step 311. In step 311, the parameter map generation unit 352 generates a two-dimensional (or three-dimensional) parameter map from the phase (period) shift amount quantified in step 310. In this case, a numerical value corresponding to the amount of phase (period) deviation is associated with, for example, a color gradation, and this color display represents the degree of phase (period) deviation in the non-periodic region of the myocardial inner wall 43. ing. The amount of phase (period) deviation can also be displayed by color coding.

  Then, the process proceeds to step 312. In step 312, the 3D image 52 of the heart obtained from the CT image data by the overlay display unit 353, as shown in FIG. 5, is obtained from the CT image data by the two-dimensional (or three-dimensional) parameter map 51 generated by the parameter map generation unit 352. The images are superimposed on each other and displayed on the display device 36. In this case, for the three-dimensional image 52 of the heart, cardiac CT image data for one volume generated from data stored in the image storage unit 34 is used. In this case, it is desirable that the three-dimensional image 52 of the heart displays the coronary artery 53 and the coronary vein 54.

  Therefore, in this way, an X-ray diagnostic apparatus that exposes a subject to X-rays and obtains image data by X-rays transmitted through the subject, wherein at least one of the heart is obtained from the obtained image data. Capture multiple volumes of image data for the heart rate, detect the heart axis that is the center of the heart's left ventricular chamber movement from this image data, and from the heart axis to different region positions on the myocardial wall of the left ventricular lumen The distance change amount is converted into a periodic function, and a region of the myocardial wall whose period is shifted is detected based on the periodic function, and the shift amount is obtained. As a result, it is possible to accurately know the region of the myocardial wall in the left ventricular cavity that is out of period, and from this result, it is possible to stably evaluate the synchronized state with high accuracy.

  Also, a two-dimensional or three-dimensional parameter map 51 representing the amount of period deviation is generated, and this parameter map is displayed superimposed on the three-dimensional image 52 of the heart obtained from CT image data. As a result, the synchronization of the motion of the heart can be visualized and displayed, so that the parameter map 51 is superimposed on the three-dimensional image 52 of the heart on which the coronary artery 53, the coronary vein 54, and the like are displayed, thereby synchronizing with the anatomical information. Information can be observed at the same time, and can be used for treatment planning, such as being able to be used as a guide for the electrode installation position for applying electrical stimulation to abnormal parts during treatment.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, in the above-described embodiment, the period deviation amount is displayed in the parameter map, but may be represented by a change graph.

  Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

1 is a diagram showing a schematic configuration of an X-ray diagnostic apparatus according to a first embodiment of the present invention. FIG. 3 is a diagram illustrating a schematic configuration of an image processing unit applied to the first embodiment. The flowchart for demonstrating the effect | action of 1st Embodiment. The figure explaining the change graph which shows the distance variation | change_quantity from the axis of 1st Embodiment. The figure which shows the state which superimposed the parameter map on the three-dimensional image of the heart of 1st Embodiment.

Explanation of symbols

P ... object 10 ... gantry device 11 ... rotating gantry 12 ... X-ray source 13 ... X-ray detector 14 ... high voltage generator 15 ... gantry driving unit 16 ... diaphragm driving unit 17 ... data collecting unit 20 ... Bed device 21 ... Bed top plate, 22 ... Bed base 23, Bed bed drive unit, 30 ... Console unit 31 ... Control unit, 32 ... Console I / F unit 33 ... Reconstruction processing unit, 34 ... Image storage unit 35 ... Image processing unit, 351 ... displacement amount calculating means 352 ... parameter map generating means 353 ... overlapping display means, 36 ... display device 37 ... input unit, 41 ... left ventricular lumen 42 ... cardiac axis, 43 ... myocardial inner wall 51 ... parameter Map, 52 ... 3D image

Claims (7)

In an X-ray CT apparatus that exposes X-rays to a subject and acquires image data by X-rays transmitted through the subject,
A distance change amount from a predetermined position is calculated for each of a plurality of regions on the myocardial wall of the left ventricular cavity from image data of a plurality of volumes taken for at least one heartbeat of the heart from the image data, A deviation amount calculating means for obtaining a phase deviation amount of the periodic change of the distance change amount ,
Display image generation means for generating a parameter map or a change graph representing the phase shift amount;
An X-ray CT apparatus comprising: 2. The display image generating unit according to claim 1, further comprising a superimposed display unit that superimposes and displays a parameter map representing the phase shift amount on a three-dimensional image of the heart obtained from the image data. X-ray CT system. The shift amount calculation means, from the image data, the first means for capturing image data of a plurality volumes for at least one heartbeat of the heart as a subject, the movement of the left ventricle cavity of the heart from the image data A second means for detecting a central axis, a third means for calculating a periodic function based on a distance change amount from the axis to each of the plurality of areas , and the calculated for each of the areas The X-ray CT apparatus according to claim 1, further comprising: a fourth unit that detects a region of the myocardial wall having a phase shift of a periodic function and obtains the phase shift amount. Myocardial wall of the left ventricle cavity is divided into a plurality of regions,
The X-ray CT apparatus according to claim 3 , wherein each of the plurality of regions is associated with the plurality of volumes. The periodic function to detect positive and negative at least one peak from the, set said detected peak time as each value of the plurality of regions, what is a significant difference for the set value of the phase The X-ray CT apparatus according to claim 3, wherein the X-ray CT apparatus detects the deviation.   For the determination of the significant difference, a relative value of (heart rate × (1/20) msec) or a statistical standard deviation value statistically obtained from each whole region of the myocardial wall is used as a threshold value. The X-ray CT apparatus according to claim 5. In a medical image processing apparatus that displays an image based on a medical image collected by an X-ray CT apparatus,
A distance change amount from a predetermined position is calculated for each of a plurality of regions on the myocardial wall of the left ventricular cavity from image data of a plurality of volumes captured for at least one heartbeat of the heart, and the distance change for each of the regions A deviation amount calculating means for obtaining a phase deviation amount of the periodic change of the quantity;
A medical image processing apparatus, comprising: a display map generating unit configured to generate a parameter map or a change graph representing the phase shift amount.

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