JP2012000323A - 3d image forming apparatus, 3d image forming program and 3d image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a 3D image data for three-dimensionally showing the distribution of the movement of blood vessels.SOLUTION: An image acquiring section 42 chronologically acquires 3D image data three-dimensionally showing the structure of the body of a subject to which an angiography agent is prescribed in linkage with the acquisition of electrocardiogram waveform data by an electrocardiogram waveform acquiring section 41. An extracting section 43 extracts regions indicating the blood vessels on the basis of voxel values for each of a plurality of 3D image data acquired by the image acquiring section 42 at one pulse cycle indicated by the electrocardiogram waveform data to extract 3D blood vessel image data. A distribution image generating section 44 generates movement distribution image data for three-dimensionally indicating the movement distribution of the blood vessels by superimposing the 3D blood vessel image data generated by the extracting section 43.

Description

  The present invention relates to a technique for processing three-dimensional image data of a blood vessel imaged using an X-ray CT apparatus or the like.

  Estimating the degree of progression of cerebral vascular arteriosclerosis and rupture of the wall of a cerebral aneurysm is one of the most important concerns for doctors involved in cerebrovascular disorders. In recent years, with the development of CT scan, MRI, and the like, it has become possible to display the internal structure of the blood vessels of the brain as a three-dimensional image. We estimated the degree of progression and the prediction of rupture of the wall of the cerebral aneurysm. Such estimation often relies on the experience and intuition of doctors, and is difficult for inexperienced doctors. If the movement of each part of the blood vessel, that is, the distribution of the movement of the blood vessel can be quantitatively shown based on the three-dimensional image, such an estimation can be easily performed. Based on this, the distribution of the movement of blood vessels has not been quantitatively shown.

  For example, in Patent Document 1, an X-ray tube that irradiates a subject with X-rays and an X-ray detector that detects X-rays transmitted through the subject are rotated around the subject to obtain projection data. A volume image is generated by reconstructing each projection data set from a plurality of projection data acquired in series and obtained from the X-ray tube angle from 0 ° to 180 ° + α. An X-ray computed tomography apparatus that displays the generated volume image in time series according to the heartbeat time phase is disclosed.

  In Patent Document 2, a subject is irradiated with a magnetic field, magnetic resonance signal data is acquired, three-dimensional volume data is generated from the acquired magnetic resonance signal data, and stored in a storage unit. There is disclosed an image display device that reads out and displays three-dimensional volume data corresponding to a designated time phase from a storage unit when the time phase is designated.

  In Patent Literature 3, a mask image (M) is obtained by irradiating a subject with radiation before the injection of the angiographic contrast agent, and a time-series live image ( L1 to Li), subtract images are generated by subtracting the mask image M from the acquired live images (L1 to Li), peak hold processing is performed on each generated substruction image, and peak hold is performed. An image obtained by generating an image (P1 to Pi), generating a plurality of PTID images by taking a difference between two peak hold images moving back and forth in time series, and superimposing the generated plurality of PTID images Is disclosed.

  In recent years, blood vessels in the brain are visualized non-invasively and three-dimensionally using MRA or CTA (for example, Non-Patent Documents 1 and 2).

JP 2008-132313 A JP 2009-153966 A Japanese Patent Laid-Open No. 6-165035

Ross JS, Masaryk TJ, Modic MT, Harik SI, Wiznitzer M, & Selman WR (1989) Neurology 39, 1369-1376. 7. Ross JS, Masaryk TJ, Modic MT, Ruggieri PM, Haacke EM, & Selman WR (1990) AJR Am J Roentgenol 155, 159-165.

  However, the techniques described in Patent Documents 1 and 2 merely display volume images in time series according to the heartbeat time phase, and do not show the distribution of blood vessel movement at all. In addition, the technique described in Patent Document 3 is intended to generate an image showing the flow of a contrast agent, and no image showing a blood vessel motion distribution is generated at all.

  Further, in each of the methods of Non-Patent Documents 1 and 2, since the three-dimensional image data of the blood vessel is statically generated and the three-dimensional image data of the blood vessel is not generated in time series, the movement of the blood vessel It is impossible to calculate the distribution of.

  An object of the present invention is to provide a three-dimensional image forming apparatus or the like that generates three-dimensional image data that three-dimensionally shows the distribution of blood vessel motion.

  (1) A three-dimensional image forming apparatus according to the present invention includes an electrocardiographic waveform acquisition unit that acquires electrocardiographic waveform data of a subject, and angiography in conjunction with the acquisition of the electrocardiographic waveform data by the electrocardiographic waveform acquisition unit. Acquired by the image acquisition unit in a predetermined period indicated by the electrocardiographic waveform data, and an image acquisition unit that acquires, in a time series, three-dimensional image data indicating the internal structure of the subject to which the agent is administered in three dimensions For each of a plurality of three-dimensional image data, an extraction unit that extracts a region indicating a blood vessel based on a voxel value and generates three-dimensional blood vessel image data; and the three-dimensional blood vessel image data generated by the extraction unit A distribution image generation unit that generates motion distribution image data that is superimposed and generates a three-dimensional motion distribution of the blood vessels.

  The three-dimensional image forming program according to the present invention includes an electrocardiographic waveform acquisition unit that acquires electrocardiographic waveform data of a subject, and an angiographic agent in conjunction with the acquisition of the electrocardiographic waveform data by the electrocardiographic waveform acquisition unit. An image acquisition unit that acquires, in a time series, three-dimensional image data indicating the structure of the body of the subject to which a dose is administered, and a plurality of images acquired by the image acquisition unit in a predetermined period indicated by the electrocardiogram waveform data A three-dimensional blood vessel image data generated by the extraction unit that extracts a region indicating a blood vessel and generates three-dimensional blood vessel image data based on the voxel value is superimposed on each of the three-dimensional image data Then, the computer is caused to function as a distribution image generating unit that generates motion distribution image data that three-dimensionally shows the distribution of the blood vessel motion.

  Further, in the three-dimensional image forming method according to the present invention, the computer acquires an electrocardiographic waveform acquisition step in which the electrocardiographic waveform data of the subject is acquired, and the computer interlocks with the acquisition of the electrocardiographic waveform data in the electrocardiographic waveform acquisition step An image acquisition step of acquiring in time series three-dimensional image data indicating a three-dimensional structure of the body of the subject to which the angiographic agent is administered, and a computer in a predetermined period indicated by the electrocardiographic waveform data An extraction step for generating a three-dimensional blood vessel image data by extracting a region indicating a blood vessel based on a voxel value for each of a plurality of three-dimensional image data acquired by the image acquisition step; The 3D blood vessel image data extracted in the step is superimposed, and the motion distribution image data showing the blood vessel motion distribution in 3D. And a distribution image generating step of generating.

  According to these configurations, a region indicating a blood vessel is extracted from the three-dimensional image data acquired in time series by the image acquisition unit in a predetermined period indicated by the electrocardiogram waveform data, and three-dimensional blood vessel image data is generated. Here, since the three-dimensional image data is generated by photographing a subject to whom an angiographic agent is administered, there is a significant difference between the voxel values of the blood vessel region and the voxel values of other regions. is doing. Therefore, a region indicating a blood vessel can be extracted from the three-dimensional image data based on the voxel value.

  Then, within a certain period, the three-dimensional blood vessel image data acquired in time series is superimposed, and motion distribution image data indicating the blood vessel motion distribution three-dimensionally is generated. Since the motion distribution image data is generated by superimposing the three-dimensional blood vessel image data acquired in time series within a certain period, the voxel value of the place where the blood vessel always exists shows the highest value, and the blood vessel The voxel value at the moved position is 1 or more and less than the maximum value, and the voxel values at other positions are 0.

  Therefore, the motion distribution image data can be expressed by distinguishing between locations where blood vessels always exist and locations indicating the motion of blood vessels, and is generated as image data indicating the distribution of blood vessel motion three-dimensionally. As a result, the user can easily visually recognize how much the blood vessel has moved at each position by comparing the size of the region where the blood vessel is always present and the region indicating the movement of the blood vessel.

  (2) The distribution image generation unit extracts, from the motion distribution image data, a trunk region indicating a region where the blood vessel does not move and a moving region indicating a region where the blood vessel moves based on a voxel value. It is preferable to do.

  According to this configuration, a region having no blood vessel movement is extracted as a trunk region from a voxel value of the motion distribution image data, and a region having blood vessel movement is extracted as a movement region. Therefore, by distinguishing and displaying these regions, it is possible to provide the user with motion distribution image data that quantitatively indicates the distribution of blood vessel motion.

  (3) It is preferable to further include an elasticity calculation unit that calculates the elasticity of the blood vessel based on the trunk region and the moving region.

  According to this configuration, since the motion distribution image data is generated by superimposing the three-dimensional blood vessel image data for a certain period, the moving area is represented so as to cover the trunk area. For this reason, a position where the width of the moving region is large indicates that the blood vessel moves greatly and the elasticity of the wall is high. On the other hand, a position where the width is small indicates that the movement of the blood vessel is small and the elasticity of the wall is low. Therefore, for example, if the volume ratio between the trunk region and the moving region is obtained, the elasticity of the blood vessel can be calculated.

  (4) It is preferable that the distribution image generation unit displays the motion distribution image data by distinguishing the trunk region and the moving region.

  According to this configuration, since the trunk region and the moving region are displayed separately, the user can easily recognize the distribution of blood vessel movement.

  (5) It is preferable that the extraction unit sets one heartbeat cycle of the electrocardiographic waveform data as the predetermined period.

  According to this configuration, since the motion distribution image data is generated using the three-dimensional image data acquired in time series in one heartbeat cycle of the electrocardiogram waveform data, the motion distribution indicating the blood vessel movement in one heartbeat cycle. Image data can be obtained, and motion distribution image data in which blood vessel features are accurately represented can be obtained.

  (6) Preferably, the one heartbeat period is a period from when an R wave peak appears until a next R wave peak appears.

  According to this configuration, since one heartbeat cycle is detected by detecting a peak of an R wave having a steep peak in one heartbeat cycle of the electrocardiographic waveform data, one heartbeat cycle can be detected with high accuracy. Can do.

  (7) It is preferable that the image acquisition unit acquires three-dimensional image data of the subject's brain.

  According to this configuration, it is possible to obtain motion distribution image data indicating the distribution of blood vessels in the brain.

  According to the present invention, it is possible to generate three-dimensional image data that three-dimensionally shows the distribution of blood vessel motion.

1 is a block diagram illustrating an overall configuration of a three-dimensional image forming apparatus according to an embodiment of the present invention. 3 is a flowchart showing an operation of the three-dimensional image forming apparatus. It is the figure which showed the acquisition timing of electrocardiogram waveform data and three-dimensional image data. (A) is the figure which showed typically a mode that 3D blood-vessel image data was extracted from 3D image data. (B) is a diagram schematically showing how motion distribution image data is generated from three-dimensional blood vessel image data. It is the screen figure which showed an example of the motion distribution image. It is the graph which showed the calculation result of the elasticity of each site | part of the blood vessel of the brain calculated by the elasticity calculation part. 5 is a graph showing changes in blood vessel volume when the left PCA is a region of interest in the three-dimensional image data obtained according to the present embodiment. It is the graph which showed the change of the volume of the blood vessel in each of eight site | parts of the blood vessel of a brain.

  Hereinafter, a three-dimensional image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a three-dimensional image forming apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the three-dimensional image forming apparatus 1 includes a three-dimensional image photographing device 10, an operation unit 20, a display unit 30, and a calculation unit 40.

  The 3D image capturing apparatus 10 includes an electrocardiogram waveform measuring unit 11 and a 3D image capturing unit 12. The three-dimensional image capturing apparatus 10 can employ, for example, a CT scan. In this embodiment, Aquilion ONE (registered trademark) manufactured by Toshiba Medical Systems Co., Ltd. is employed. This CT scan has 320 rows of area detectors, can capture 3D image data inside the subject's body without moving the subject, and can acquire 3D image data with a high S / N ratio at high speed. Can do.

  The electrocardiogram waveform measurement unit 11 is constituted by, for example, an electrocardiograph, detects an electrocardiogram waveform representing a time change of an action potential reflecting the heartbeat (heartbeat motion) of the subject, and outputs an electrocardiogram as electrocardiogram waveform data. Output to the shape acquisition unit 41. Here, the electrocardiogram waveform data is a data group in which the value of the action potential at each time is represented as a digital value, and is composed of a data group in which a digital value at each time is associated with a time code indicating the measurement time. Yes.

  The three-dimensional image capturing unit 12 uses a X-ray tube that irradiates the subject with X-rays, an area detector that detects X-rays transmitted through the subject, and two-dimensional image data obtained by the area detector. A reconstruction unit for generating data is provided. In the present embodiment, the three-dimensional image capturing unit 12 has a frame rate set so that, for example, ten pieces of three-dimensional image data can be acquired in one heartbeat cycle of the electrocardiographic waveform data. In the present embodiment, the three-dimensional image photographing unit 12 photographs a subject to whom an angiographic agent is administered, and generates CTA that is three-dimensional CT image data subjected to angiography.

  The operation unit 20 is configured by an input device such as a keyboard and a mouse, for example, and accepts various operation commands from the user. In the present embodiment, the operation unit 20 includes an operation command indicating the start of shooting from the user, an operation command for displaying the captured 3D image data on the display unit 30, and the captured 3D image data as a 2D image. An operation command for setting a line of sight for display and an operation command for displaying a motion distribution image on the display unit 30 are received.

  The calculation unit 40 is configured by a computer including, for example, a CPU, a ROM, a RAM, a recording medium driving device, and a hard disk, and includes an electrocardiogram waveform acquisition unit 41, an image acquisition unit 42, an extraction unit 43, a distribution image generation unit 44, An elasticity calculation unit 45 and a display control unit 46 are provided. These functions are realized by the CPU executing a three-dimensional image forming program for causing the computer to function as the three-dimensional image forming apparatus 1.

  This three-dimensional image forming program may be provided to the user by storing it on a computer-readable recording medium such as a CD-ROM, or may be provided to the user by downloading it from a server via a network. Good. Alternatively, a commercially available CT scan program module may be mounted on the CT scan, or may be integrated and mounted on the CT scan.

  The electrocardiogram waveform acquisition unit 41 acquires the electrocardiogram waveform data output from the electrocardiogram waveform measurement unit 11. The image acquisition unit 42 acquires 3D image data captured by the 3D image capturing unit 12. In the present embodiment, the image acquisition unit 42 is linked to the acquisition of the electrocardiogram waveform data by the electrocardiogram waveform acquisition unit 41, and is a three-dimensional image that shows the structure in the body of the subject to which the angiographic contrast agent is administered in three dimensions. Get data in time series. Hereinafter, the image acquisition unit 42 acquires three-dimensional image data of the subject's brain.

  Specifically, when the extraction unit 43 detects an R wave peak, the image acquisition unit 42 receives a synchronization command from the extraction unit 43. Then, the image acquisition unit 42 outputs a data output command for outputting the three-dimensional image data to the three-dimensional image photographing unit 12 at a constant time interval synchronized with the input timing of the synchronization command, and outputs the three-dimensional image photographing unit 12 12 to output 3D image data synchronized with the peak timing of the R wave. Thereby, the image acquisition unit 42 can acquire 10 pieces of three-dimensional image data synchronized with the peak timing of the R wave.

  Here, the three-dimensional image data is image data in which a plurality of voxels having a minute rectangular parallelepiped shape or a cubic shape are three-dimensionally arranged in a predetermined number of vertical × horizontal × height directions. Each voxel represents the internal structure of the subject's brain using a predetermined number of bits of voxel values. In the present embodiment, since the three-dimensional image photographing unit 12 photographs a subject to whom an angiographic contrast agent has been administered, in the three-dimensional image data, a voxel value in a blood vessel region and a voxel value in another region Appears with a significant difference. Hereinafter, it is assumed that the blood vessel region has a higher voxel value than the other regions.

  The extraction unit 43 extracts a region indicating a blood vessel based on the voxel value for each of a plurality of three-dimensional image data acquired by the image acquisition unit 42 in one heartbeat cycle indicated by the electrocardiogram waveform data. Dimensional blood vessel image data is generated. In the present embodiment, ten pieces of three-dimensional image data are acquired in one heartbeat period, and thus the extraction unit 43 generates ten pieces of three-dimensional blood vessel image data.

  Here, when the extraction unit 43 detects the peak timing of the R wave appearing in the electrocardiogram waveform data, the extraction unit 43 outputs a synchronization command to the image acquisition unit 42. Then, the extraction unit 43 sets the 10 pieces of image data acquired by the image acquisition unit 42 in synchronization with the peak timing of the R wave as a group of image data sets.

  Then, the extraction unit 43 performs a process of extracting a region indicating a blood vessel for each of the three-dimensional image data constituting the group of image data sets, and the three-dimensional blood vessel image corresponding to each three-dimensional image data Generate data.

  Here, as a process of extracting a region indicating a blood vessel, for example, a predetermined threshold value is compared with each voxel value constituting the three-dimensional image data, and “1” is set for a voxel having a voxel value equal to or larger than the threshold value. For example, a binarization process in which a voxel value is less than a threshold value and labeled with “0” can be employed.

  Since the 3D image capturing unit 12 captures the subject to whom the angiographic contrast agent is administered, the 3D image data has a higher voxel value in the voxel indicating the blood vessel region than in the voxel indicating the other region. is doing. Therefore, by the binarization processing, the blood vessel region is indicated by 1 and the other regions are indicated by 0, and three-dimensional blood vessel image data that three-dimensionally shows the blood vessel region can be obtained. As the threshold value, a value slightly lower than the voxel value assumed to indicate a blood vessel portion in the three-dimensional image data obtained when a subject to whom an angiographic contrast agent is administered is taken may be adopted. As described above, a group of blood vessel image data sets composed of three-dimensional blood vessel image data corresponding to the respective three-dimensional image data constituting the group of image data sets is obtained.

  The distribution image generation unit 44 superimposes the 10 pieces of three-dimensional blood vessel image data constituting the group of blood vessel image data sets generated by the extraction unit 43, thereby moving the movement of the blood vessels in a three-dimensional manner. Distribution image data is generated.

  Here, the blood vessel image data has a voxel value of 1 for a region indicating a blood vessel and 0 for other regions. Therefore, in the motion distribution image data, the voxel where the blood vessel always exists has a voxel value of “10”, the voxel where the blood vessel moved has a voxel value of 1 to 9, and other voxels. Has a voxel value of zero.

  The distribution image generation unit 44 extracts a region composed of voxels having a voxel value of “10” as a trunk region (hereinafter referred to as “CORE region”), and a region composed of voxels having a voxel value of 1 to 9 inclusive. It is extracted as a moving area (hereinafter referred to as “HALO area”).

  Then, the distribution image generation unit 44 displays the motion distribution image on the display unit 30 while distinguishing between the CORE region and the HALO region. Thereby, a motion distribution image in which the HALO area is represented so as to cover the CORE area is displayed. Therefore, the user can recognize how much the blood vessel has moved from the size of the HALO area with respect to the CORE area, and can provide a motion distribution image in which the movement is quantitatively shown. Here, the movement of the blood vessel includes expansion and contraction of the blood vessel for circulating blood and movement of the position of the blood vessel itself. In addition, as a display mode when the CORE region and the HALO region are displayed separately, for example, a mode in which both regions are displayed in different colors or a mode in which light and shade are displayed according to the voxel value may be employed.

  The elasticity calculation unit 45 calculates the elasticity of the blood vessel based on the ratio between the CORE area and the HALO area indicated by the motion distribution image data. Here, the elasticity calculation unit 45 sets the region of interest in the motion distribution image data, for example, according to the user's operation command, and calculates the elasticity by calculating HALO / (HALO + CORE) in the region of interest. That's fine.

  The display control unit 46 renders the motion distribution image data generated by the distribution image generation unit 44 and displays the motion distribution image on the display unit 30. The display unit 30 is configured by a display device such as a liquid crystal panel, a plasma panel, or an organic EL panel, and displays a motion distribution image.

  Next, the operation of the three-dimensional image forming apparatus 1 will be described. FIG. 2 is a flowchart showing the operation of the three-dimensional image forming apparatus 1. First, the electrocardiogram waveform acquisition unit 41 causes the electrocardiogram waveform measurement unit 11 to start measuring electrocardiogram waveform data and starts acquiring electrocardiogram waveform data (step S1).

  Next, the extraction unit 43 detects the peak of the R wave from the electrocardiogram waveform data acquired by the electrocardiogram waveform acquisition unit 41 (step S2). FIG. 3 is a diagram showing the acquisition timing of the electrocardiographic waveform data and the three-dimensional image data.

  The upper graph shows an example of the electrocardiogram waveform W1. One heartbeat period TM of the electrocardiogram waveform W1 is composed of an R wave, an S wave, a T wave, a P wave, and a Q wave. Here, the R wave has a steep and convex peak. Therefore, by setting the peak of the R wave, it is possible to detect the start timing of one heartbeat cycle with high accuracy.

  Returning to FIG. 2, in step S <b> 3, the image acquisition unit 42 receives the synchronization command from the extraction unit 43 and causes the 3D image capturing unit 12 to start outputting 3D image data, thereby acquiring the 3D image data. To start. Here, as shown in FIG. 3, when the elapsed time from the start time of one heartbeat period TM is 0%, that is, when an R wave is detected, the image acquisition unit 42 detects the first three-dimensional image data. When GD1 is acquired and the elapsed time from the start time of one heartbeat period TM is 10%, the second three-dimensional image data GD2 is acquired, and so on in the one heartbeat period TM, Three-dimensional image data GD1 to GD10 are acquired as a group of image data sets. The acquired three-dimensional image data GD1 to GD10 are stored in a memory (not shown).

  Next, the extraction unit 43 extracts a region indicating a blood vessel from each of the three-dimensional image data GD1 to GD10 acquired in step S3, and generates three-dimensional blood vessel image data GE1 to GE10 (step S4).

  FIG. 4A is a diagram schematically illustrating how the three-dimensional blood vessel image data GE1 to GE10 are extracted from the three-dimensional image data GD1 to GD10. As shown in FIG. 4A, it can be seen that three-dimensional blood vessel image data GE1 to GE10 corresponding to each of the three-dimensional image data GD1 to GD10 are obtained.

  Next, the distribution image generation unit 44 generates motion distribution image data GF by superimposing the three-dimensional blood vessel image data GE1 to GE10 (step S5). FIG. 4B is a diagram schematically showing how the motion distribution image data GF is generated from the three-dimensional blood vessel image data GE1 to GE10. In FIG. 4B, ten disc-shaped objects indicate blood vessel regions BR1 to BR10 that appear in the three-dimensional blood vessel image data GE1 to GE10. As shown in FIG. 4B, three-dimensional blood vessel image data GE1 to GE10 are superimposed to generate one piece of motion distribution image data GF.

  Next, the distribution image generation unit 44 extracts the CORE region and the HALO region from the motion distribution image data GF (step S6). In FIG. 4B, the region B1 is composed of voxels having a voxel value of 10 because the blood vessel regions BR1 to BR10 are always located. Therefore, the area B1 is extracted as a CORE area. On the other hand, the region B2 is composed of voxels having voxel values 1 to 9 because the blood vessel regions BR1 to BR10 exist once, but the blood vessel regions BR1 to BR10 do not always exist. Therefore, the area B2 is extracted as a HALO area.

  Next, the distribution image generation unit 44 outputs a drawing command for displaying the motion distribution image in which the CORE region and the HALO region are color-coded on the display unit 30 to the display control unit 46, and the display control unit 46. Renders the motion distribution image data based on the viewpoint designated by the user to generate a motion distribution image and displays it on the display unit 30 (step S7).

  FIG. 5 is a screen diagram illustrating an example of a motion distribution image. The motion distribution image shown in FIG. 5 shows PCAs (Posterior Cerebral arteries) on both sides. As shown in FIG. 5, it can be seen that the HALO area is displayed so as to cover the CORE area. Therefore, the user can recognize the movement of each position of the blood vessel from the width WD1 of the HALO region. That is, the position where the width WD1 is large indicates that the blood vessel moves greatly and the elasticity of the wall is high. On the other hand, a position where the width WD1 is small indicates that the movement of the blood vessel is small and the elasticity of the wall is low. In this way, the user can recognize the elasticity of each position of the blood vessel.

  Next, when the operation unit 20 receives an operation command for setting an impression area (ROI) from the user (YES in step S8), the elasticity calculation unit 45 calculates the volume of the CORE area and the volume of the HALO area in the ROI. And the elasticity of ROI is obtained by calculating HALO / (HALO + CORE) (step S9). Here, the user may set the ROI by, for example, operating the operation unit 20 and performing an operation of designating a desired ROI among the motion distribution images displayed on the display unit 30. As an operation for setting the ROI, an operation of drawing a rectangular parallelepiped outline on the display screen by dragging the mouse and surrounding a desired region with the outline may be adopted. Alternatively, the elasticity calculator 45 may automatically calculate the elasticity for a predetermined blood vessel site.

  The cerebral blood vessels include left (Lt) right (Rt) internal carotid arteries (ICA), left and right MCA (middle cerebral arteries), Acom (Acom complex), BA (basilar artery bifurcation), and left and right PCAs. Exists. Therefore, the elasticity calculation unit 45 divides the motion distribution image data by a predetermined area where each of these areas is estimated, and obtains HALO / (HALO + ROI) in each divided area. What is necessary is just to calculate the elasticity of a site | part.

  On the other hand, if the operation unit 20 does not accept an operation command for designating ROI in step S8 (NO in step S8), the process returns to step S8. In addition, when the aspect in which the elasticity calculation part 45 calculates the elasticity of each predetermined area | region is employ | adopted, you may abbreviate | omit the process of step S8.

  FIG. 6 is a graph showing the calculation result of the elasticity of each part of the cerebral blood vessel calculated by the elasticity calculator 45, where the vertical axis indicates the elasticity and the horizontal axis indicates the part. As the sites, eight ICA of left and right ICA, left and right MCA, Acom, BA, and left and right PCA were adopted, and the average value of 10 subjects was plotted for each site.

  The age of 10 subjects is 53-77 years, the average age is 69 years, and the median is 70 years. As an angiographic agent, Optiray (registered trademark) manufactured by Covidien Japan was used. This contrast agent was administered to each patient via a 20G IV catheter using Dual-Shot GX (registered trademark) manufactured by Nemoto Kyorindo.

  In Aquilion ONE (registered trademark) adopted as the three-dimensional image capturing apparatus 10, various parameters are set such that the tube voltage is 120 kV, the tube current is 270 mA, the gantry rotation period is 350 msec, and 10 frames are set for one heartbeat period. Three-dimensional image data was generated. As the three-dimensional image data, volume data composed of 512 × 512 × 640 voxels was adopted.

  0.206, 0.201, 0.315, 0.311, 0.322, 0.336, 0.394, 0.398 for left and right ICA, left and right MCA, Acom, BA, and left and right PCA, respectively The degree of elasticity was calculated. From this result, it can be seen that the left and right PCAs have a thicker HALO region and higher elasticity than other parts.

  If the left and right ICAs are group GR1, the left and right MCA, Acom, and BA are group GR2, and the left and right PCAs are group GR3, the P values of groups GR1 and GR2 are P <0.05, and groups GR1 and GR3 The P value was P <0.001, and a significant difference was observed in each group.

  In addition, it is known that each part of the group GR1 has less blood vessel movement than each part of the group GR2, and each part of the groups GR1 and GR2 has less blood vessel movement than the group GR3. It is known. Therefore, it can be seen from these empirical rules and the P value that the elasticity calculated by the present embodiment indicates an appropriate movement index according to each part of the blood vessel of the brain.

  FIG. 7 is a graph showing changes in blood vessel volume when the left PCA is the region of interest in the three-dimensional image data obtained according to the present embodiment, and the vertical axis shows the blood vessel volume. The horizontal axis indicates the elapsed time of one heartbeat cycle in%. Note that the time of 0% indicates the peak time of the R wave. In FIG. 7, the volume of the blood vessel is calculated in each of 10 pieces of three-dimensional image data acquired at a time of 0%, 10%, 20%,. .

  In calculating the volume, as described above, ten pieces of three-dimensional blood vessel image data are generated from ten pieces of three-dimensional image data, and the number of voxels having a voxel value of 1 in the obtained three-dimensional blood vessel image data is counted. What is necessary is just to calculate.

  As shown in FIG. 7, a convex peak is obtained when the elapsed time is 30% to 40%, a convex peak is obtained when the elapsed time is 60%, and a wave having two characteristic peaks. Has been observed.

  FIG. 8 is a graph showing changes in blood vessel volume in each of the eight regions of the blood vessels of the brain, with the vertical axis showing the change in blood vessel volume and the horizontal axis showing each region. Here, the change in the volume of the blood vessel is the difference between the upwardly convex peak and the downwardly convex peak in the graph of FIG. As shown in FIG. 8, in the change of the volume of the blood vessel, no significant difference was observed for each part.

  In the above flowchart, the ROI is specified after the motion distribution image is displayed. However, the present invention is not limited to this, and may be performed before obtaining the three-dimensional image data. In this case, the imaging range of the subject is narrowed, the number of voxels in the 3D image data is reduced, and the processing burden when generating 3D image data, 3D blood vessel image data, and motion distribution image data can be reduced. .

  In the above embodiment, the motion distribution image data for only one heartbeat cycle is generated. However, the present invention is not limited to this, and one motion distribution image data is generated every time one heartbeat cycle elapses. The distribution image data may be generated continuously in time series.

  In the above embodiment, motion distribution image data of blood vessels in the brain is generated. However, the present invention is not limited to this, and motion distribution image data of blood vessels in the body of the subject other than the brain may be generated.

  In the above embodiment, 3D image data generated by CT scan is used. However, the present invention is not limited to this, and 3D image data generated by another 3D medical image generation device such as MRA is used. May be.

  In the above embodiment, 10 pieces of 3D image data are acquired in one heartbeat cycle. However, the present invention is not limited to this, and 2 to 9 pieces of 11 or more pieces of 3D image data may be acquired.

DESCRIPTION OF SYMBOLS 1 3D image formation apparatus 10 3D image imaging device 11 ECG waveform measurement part 12 3D image imaging part 20 Operation part 30 Display part 40 Calculation part 41 Electrocardiogram waveform acquisition part 42 Image acquisition part 43 Extraction part 44 Distribution image generation Unit 45 elasticity calculation unit 46 display control unit

Claims (9)

An electrocardiographic waveform acquisition unit for acquiring electrocardiographic waveform data of the subject;
In conjunction with the acquisition of the electrocardiographic waveform data by the electrocardiographic waveform acquisition unit, an image acquisition unit that acquires, in time series, three-dimensional image data that shows in three dimensions the internal structure of the subject to which the angiographic contrast agent has been administered. When,
For each of a plurality of three-dimensional image data acquired by the image acquisition unit in a predetermined period indicated by the electrocardiogram waveform data, a region indicating a blood vessel is extracted based on the voxel value to obtain the three-dimensional blood vessel image data. An extractor to generate;
A three-dimensional image forming apparatus comprising: a distribution image generation unit configured to superimpose the three-dimensional blood vessel image data generated by the extraction unit and generate motion distribution image data indicating the distribution of the blood vessel motion three-dimensionally.   The distribution image generation unit extracts, from the motion distribution image data, a trunk region indicating a region where the blood vessel does not move and a moving region indicating a region where the blood vessel moves based on a voxel value. The three-dimensional image forming apparatus according to 1.   The three-dimensional image forming apparatus according to claim 2, further comprising an elasticity calculation unit that calculates the elasticity of the blood vessel based on the trunk area and the moving area.   The three-dimensional image forming apparatus according to claim 2, wherein the distribution image generation unit displays the motion distribution image data by distinguishing the trunk region and the moving region.   The three-dimensional image forming apparatus according to any one of claims 1 to 4, wherein the extraction unit sets one heartbeat cycle of the electrocardiographic waveform data as the predetermined period.   6. The three-dimensional image forming apparatus according to claim 5, wherein the one heartbeat period is a period from when an R wave peak appears until a next R wave peak appears.   The three-dimensional image forming apparatus according to claim 1, wherein the image acquisition unit acquires three-dimensional image data of the subject's brain. An electrocardiographic waveform acquisition unit for acquiring electrocardiographic waveform data of the subject;
In conjunction with the acquisition of the electrocardiographic waveform data by the electrocardiographic waveform acquisition unit, an image acquisition unit that acquires, in time series, three-dimensional image data that shows in three dimensions the internal structure of the subject to which the angiographic contrast agent has been administered. When,
For each of a plurality of three-dimensional image data acquired by the image acquisition unit in a predetermined period indicated by the electrocardiogram waveform data, a region indicating a blood vessel is extracted based on the voxel value to obtain the three-dimensional blood vessel image data. An extractor to generate;
A three-dimensional image forming program for causing a computer to function as a distribution image generation unit that superimposes the three-dimensional blood vessel image data generated by the extraction unit and generates motion distribution image data that three-dimensionally represents the distribution of blood vessel motion. An electrocardiogram waveform acquisition step in which the computer acquires electrocardiogram waveform data of the subject;
In conjunction with the acquisition of the electrocardiographic waveform data in the electrocardiographic waveform acquisition step, the computer acquires three-dimensional image data showing the structure of the body of the subject to which the angiographic contrast agent is administered in three dimensions in time series. An image acquisition step;
A computer extracts a region indicating a blood vessel based on a voxel value for each of a plurality of three-dimensional image data acquired by the image acquisition step in a predetermined period indicated by the electrocardiogram waveform data, thereby generating a three-dimensional blood vessel. An extraction step for generating image data;
A three-dimensional image forming method comprising: a distribution image generating step in which a computer superimposes the three-dimensional blood vessel image data extracted in the extracting step and generates motion distribution image data indicating the distribution of blood vessel motion in three dimensions.