JP2010115317A - Image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save trouble and time for diagnostic imaging of a myocardial bridge. <P>SOLUTION: A memory unit 2 stores a volume data set relative to the heart of a subject. A blood vessel specifying unit 42 specifies the blood vessel region included in the volume data set. A myocardial bridge determining unit 45 determines whether the blood vessel region includes a myocardial bridge region or not on the basis of volume pixel values of several volume pixels surrounding the blood vessel region. A display 6 indicates information relative to the result of determination by the myocardial bridge determining unit 45. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus for diagnosing a myocardial bridge.

  A coronary artery runs through the heart wall. Normal coronary arteries pass outside the myocardium. However, some abnormal coronary arteries pass through the myocardium. This coronary artery that passes through the myocardium is called myocardial bridge. Myocardial bridging is most commonly seen in the middle of the left anterior descending coronary artery. Myocardial cross-linking is usually asymptomatic and is thought to be a long-term problem. On the other hand, there are reports that suggest an association with unstable angina, myocardial infarction, arrhythmia, and sudden death. Detection of myocardial cross-linking is difficult without the accuracy and image quality of a multi-row X-ray computed tomography apparatus having 64 rows or more. For this reason, examples of detection of myocardial cross-linking by image diagnosis are limited, and research is ongoing.

As described above, the myocardial bridge is specified by a multi-row X-ray computed tomography apparatus having 64 rows or more. In general, the presence or absence of myocardial cross-linking is diagnosed on a CT image generated by a multi-row X-ray computed tomography apparatus by a doctor's interpretation. Moreover, in order to generate an image used for evaluation of myocardial cross-linking, an engineer or a doctor sets image parameters by groping. Therefore, it takes a lot of time for engineers and doctors. In addition, the influence of myocardial cross-linking on hemodynamics is evaluated by CAG (angiography) using an X-ray diagnostic apparatus after the myocardial cross-linking is specified on a CT image. Since CAG uses a contrast medium and a catheter, the degree of invasiveness is higher than that of an X-ray computed tomography apparatus. Therefore, the examination by CAG places a heavy burden on the patient. In addition, performing inspection with a plurality of modalities is not only time-consuming but also time-consuming.
MDCT evaluation of Myocardial Bridge, Zeina AR: AJR2007; 188: 1069-1073 (May. 2007) Suppression of coronary atherosclerosis and myocardial ischemia by myocardial bridging, THE JOUNAL of JAPANESE COLLEGE of ANGIOLOGY 2003, Vol.43, No11, pp691-698

  An object of the present invention is to provide an image processing apparatus that can reduce labor and time relating to image diagnosis of myocardial cross-linking.

  An image processing apparatus according to a first aspect of the present invention includes a storage unit that stores a volume data set related to a heart of a subject, a blood vessel specifying unit that specifies a blood vessel region included in the volume data set, and surrounds the blood vessel region A determination unit that determines whether or not the blood vessel region includes a myocardial bridging region based on voxel values of a plurality of voxels to be displayed, and a display unit that displays information on a determination result by the determination unit.

  An image processing apparatus according to a second aspect of the present invention relates to a heart of a subject, a storage unit that stores a plurality of volume data sets related to a plurality of time phases, and an instruction from a user among the plurality of volume data sets. Whether or not the blood vessel region includes a myocardial bridging region based on a voxel value of a plurality of voxels surrounding the blood vessel region and a blood vessel specifying unit that specifies a blood vessel region included in a specific volume data set specified according to A determination unit for determining whether or not, and a display unit for displaying information on a determination result by the determination unit.

  According to the present invention, it is possible to reduce labor and time relating to image diagnosis of myocardial cross-linking.

  Hereinafter, an image processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. First, myocardial cross-linking for image diagnosis using the image processing apparatus according to the present embodiment will be described.

  Myocardial bridging is believed to be associated with paroxysmal atrioventricular block, ventricular fibrillation, ventricular tachycardia, WPW syndrome, hypertrophic cardiomyopathy, unstable angina, myocardial infarction, arrhythmia, and sudden death.

  Myocardial bridging has no genetic background and is a congenital and accidental anatomical variant. On average, about half of those who died of myocardial infarction and were dissected were found to have myocardial cross-linking. Myocardial bridging compresses the coronary arteries during systole, causing abnormal blood flow in the arteries and resulting myocardial ischemia. On the other hand, in the coronary artery intima covered with myocardium, the generation and progression of arteriosclerotic lesions are suppressed by the increase in blood flow shear stress.

  In cases where LAD stenosis due to compression of myocardial bridging during systole shows 75% or more, myocardial ischemic changes occur with increasing heart rate. The occurrence of myocardial ischemia due to myocardial cross-linking is strongly related to hemodynamic displacement caused by arterial compression of myocardial cross-linking during cardiac contraction. That is, blood reflux from the myocardial bridge during the systole to the ascending side, a decrease in the diameter of the coronary artery under the myocardial bridge during diastole (dilatation delay), and an increase in the blood flow velocity occur. Therefore, it is considered that myocardial ischemia occurs due to a decrease in myocardial blood flow and an imbalance in blood flow distribution. On the other hand, the insertion of a stent into the myocardial cross-linked portion and the removal of the surgical myocardial cross-linking result in avoiding milking effects and myocardial ischemic changes. These results may be evidence that myocardial cross-linking was involved.

  As a mechanism of myocardial ischemia due to myocardial cross-linking, it is considered that spasm of the arteries under myocardial cross-linking and subsequent blood vessel formation at the same site are involved. Myocardial ischemic symptoms often appear when the stenosis rate of the arteries under myocardial bridge during the systole is high, that is, when the myocardial bridge is thick. In addition, there are long-term observation cases in which coronary artery compression findings of myocardial bridging have become obvious due to the progression of cardiac hypertrophy, and follow-up is also necessary in myocardial bridging cases that do not show ischemic changes.

(First embodiment)
The image processing apparatus 1 according to the first embodiment of the present invention automatically determines the presence or absence of myocardial bridge and evaluates the position, length, and thickness of the myocardial bridge. FIG. 1 is a diagram illustrating a configuration of an image processing apparatus 1 according to the first embodiment. As illustrated in FIG. 1, the image processing apparatus 1 includes a storage unit 2, an input unit 3, an image processing unit 4, an image generation unit 5, a display unit 6, and a control unit 7.

  The storage unit 2 stores a plurality of volume data sets relating to a plurality of time phases. These volume data sets relate to the subject's heart. It is assumed that myocardial bridging occurs in the coronary artery (coronary artery) of the subject's heart. Assume that these volume data sets are generated by an X-ray computed tomography apparatus or a magnetic resonance imaging apparatus.

  The input unit 3 receives various commands and information input from the user. Specifically, the input unit 3 inputs a specific time phase from among a plurality of time phases in order to specify a volume data set to be determined for the presence or absence of myocardial cross-linking in response to an instruction from the user. . A specific time phase is one time phase. As the input unit 3, a pointing device such as a mouse or a trackball, a selection device such as a mode switch, or an input device such as a keyboard can be used as appropriate.

  The image processing unit 4 reads the volume data set related to the specific time phase input by the input unit 3 from the storage unit 2 and performs image processing to determine the presence or absence of myocardial cross-linking and evaluate myocardial cross-linking. Specifically, the image processing unit 4 includes a myocardial identification unit 41, a blood vessel identification unit 42, a segmentation unit 43, a core line identification unit 44, a myocardial bridge determination unit 45, a myocardial bridge position calculation unit 46, a myocardial bridge length calculation unit 47, And a myocardial cross-linking thickness calculator 48.

  The myocardial specifying unit 41 specifies the myocardial region included in the volume data set related to the specific time phase. The blood vessel specifying unit 42 specifies a blood vessel region included in the volume data set related to the specific time phase. The segmentation unit 43 segments (classifies) the identified blood vessel region according to the position of the part. The core line specifying unit 44 specifies the core line of the specified blood vessel region. The myocardial bridge determination unit 45 determines whether or not the blood vessel region includes a myocardial bridge region based on the voxel values of a plurality of voxels surrounding the specified blood vessel region. The myocardial cross-linking position calculation unit 46 calculates the position of the myocardial cross-linking area. The myocardial bridge length calculating unit 47 calculates the length of the myocardial bridge region. The myocardial cross-linking thickness calculation unit 48 calculates the thickness of the myocardial cross-linking region.

  The image generator 5 generates display image data based on the volume data set. For example, the image generation unit 5 generates SVR image data by performing SVR (Shaded Volume Rendering) processing on the volume data set, or generates CPR image data by performing CPR (Curved Multiple Planer Reconstruction) processing on the volume data set. To do.

  The display unit 6 displays information related to the determination result of the presence or absence of the myocardial bridge. When there is a myocardial bridge, the display unit 6 displays not only the determination result of the presence or absence of the myocardial bridge but also information regarding the position, length, and thickness of the myocardial bridge. Typically, the display unit 6 may display the display image together with the determination result of the presence or absence of myocardial cross-linking in a predetermined display layout.

  The control unit 7 functions as the center of the image processing apparatus 1. Upon receiving a request for starting myocardial cross-linking determination processing from the input unit 3, the control unit 7 controls each unit in the image processing apparatus 1 and executes myocardial cross-linking image diagnosis processing.

  Next, myocardial bridging image diagnosis processing performed under the control of the control unit 7 will be described. FIG. 2 is a diagram showing a typical flow of diagnostic imaging processing for myocardial cross-linking.

  It is assumed that the volume data set generated by the X-ray computed tomography apparatus, the magnetic resonance imaging apparatus, or the like is stored in the storage unit 2 before step SA1.

  At the start of the myocardial cross-linking image diagnostic process, the control unit 7 waits for information related to the time phase of the volume data set to be processed (step SA1). The time phase of the volume data set to be processed is, for example, a systole during which myocardial cross-linking is easily detected.

  The control unit 7 causes the myocardial specifying unit 41 to perform myocardial specifying processing when the user inputs information on the time phase via the input unit 3 (step SA1: YES). In the myocardial specifying process, the myocardial specifying unit 41 reads the input volume data set related to the time phase from the storage unit 2 and specifies the myocardial region included in the read volume data set (step SA2). Specifically, the myocardial specifying unit 41 extracts voxels having voxel values of the myocardial region from the voxels constituting the volume data set by threshold processing. Then, the myocardial specifying unit 41 writes the extracted myocardial region position (coordinate) information in the storage unit 2. The range of the voxel values in the myocardial region is not particularly described but is generally known.

  Moreover, the control part 7 makes the blood vessel specific | specification part 42 perform a blood vessel specific process triggered by the information regarding a time phase being input via the input part 3 by a user (step SA1: YES). In the blood vessel specifying process, the blood vessel specifying unit 42 reads out the volume data set related to the input time phase from the storage unit 2, and specifies the blood vessel region included in the read volume data set (step SA3). In particular. The blood vessel specifying unit 42 extracts voxels having a voxel value of the blood vessel region from each voxel constituting the volume data set by threshold processing. Then, the blood vessel specifying unit 42 writes the extracted position (coordinate) information of the blood vessel region in the storage unit 2. The range of the voxel value of the blood vessel region is generally known although not particularly described.

  When the blood vessel region is specified, the control unit 7 causes the segmentation unit 43 to perform segmentation processing. In the segmentation process, the segmentation unit 43 segments each of the plurality of branch portions constituting the blood vessel region for each classification name (step SA4). Specifically, the segmentation unit 43 determines the connection from the continuity of the voxel values from the start point of the blood vessel region input by the user via the input unit 3, and determines a series of voxels determined to be connected. Segment the vessel region as. For example, the coronary artery is classified into a left anterior descending branch, a left circumflex branch, a right coronary artery, and the like according to its anatomical position. In many cases, the myocardial cross-linking occurs in the vicinity of the proximal portion of the left anterior descending branch. The storage unit 2 stores the blood vessel region and the classification name in association with each other.

  When the blood vessel region is segmented, the control unit 7 causes the core line specifying unit 44 to perform the core line specifying process. In the core line specifying process, the core line specifying unit 44 specifies the blood vessel core line of the segmented blood vessel region (step SA5). Conventionally, various methods for identifying a blood vessel core have been developed. The core wire specifying unit 44 according to this embodiment may specify the blood vessel core wire using any of these conventional methods. For example, the core specifying unit 44 extracts a blood vessel core line by thinning the blood vessel region, and writes the extracted position (coordinate) information of the blood vessel core line in the storage unit 2. FIG. 3 is a diagram showing a positional relationship among the myocardial region 61, the blood vessel region 62, and the blood vessel core 63. As shown in FIG. 3, the blood vessel core line 63 of the blood vessel region 62 is extracted as a point sequence. The occurrence site of myocardial cross-linking is surrounded by a myocardial region 61. The extracted position information of the blood vessel region 62 is written in the storage unit 2.

  When the myocardial region and the blood vessel core line are specified, the control unit 7 causes the myocardial bridge determination unit 45 to perform determination processing. In the determination process, the myocardial bridge determination unit 45 determines whether or not the blood vessel region includes the myocardial bridge region based on the voxel values of a plurality of voxels surrounding the blood vessel region (step SA6).

  Hereinafter, the determination process by the myocardial bridge determination unit 45 will be described in detail. FIG. 4 is a diagram schematically showing a blood vessel region 62A (hereinafter referred to as a myocardial cross-linking region) related to myocardial cross-linking in a cross section orthogonal to the blood vessel core line 63 (hereinafter referred to as an orthogonal cross-section). As shown in FIG. 4, the myocardial bridge region 62 </ b> A penetrates into the myocardial region 61. Accordingly, the myocardial bridging region 62A is surrounded by the myocardial region 61 in the orthogonal cross section. In other words, the myocardial region 61 is located in the entire circumferential direction of the myocardial bridging region 62A (blood vessel core 63) in the orthogonal cross section. . As long as the myocardial bridging region 62A is surrounded by the myocardial region 61, the myocardial region 61 may or may not touch the myocardial bridging region 62A. That is, another region (for example, a fat tissue region (not shown) or the like) may be positioned between the myocardial bridging region 62A and the myocardial region 61.

  FIG. 5 is a diagram schematically showing a normal blood vessel region 62B in the orthogonal cross section. As shown in FIG. 5, the normal blood vessel region 62 </ b> B is distributed on the surface of the myocardial region 61. Therefore, the normal blood vessel region 62B is not surrounded by the myocardial region 61 in the orthogonal cross section, in other words, the myocardial region 61 is distributed only in a part of the entire circumferential direction in the orthogonal cross section. At this time, similarly to the case of the myocardial bridge, the myocardial region 61 may or may not be in contact with the myocardial bridge region 62B. That is, another region (for example, an adipose tissue region (not shown) or the like) may be located between the myocardial bridge region 62B and the myocardial region 61.

  The myocardial cross-linking determination unit 45 performs myocardial cross-linking determination processing using the arrangement relationship between the myocardial cross-linking region and the myocardial region. In the determination process, first, the myocardial bridge determination unit 45 reads position information on the myocardial region, the blood vessel region, and the blood vessel core line stored in the storage unit 2. Based on the read position information, an orthogonal cross section orthogonal to the traveling direction of the blood vessel core line is set for each voxel constituting the blood vessel core line (hereinafter referred to as a core line voxel). The myocardial bridging determination unit 45 is surrounded by a plurality of voxels having a voxel value of the myocardial region (hereinafter referred to as a myocardial voxel) within each orthogonal cross section set, that is, It is determined whether or not the myocardial region is distributed in the radial direction. The orthogonal cross section to be set does not need to be set for all the core voxels, and may be set for every predetermined number, for example.

  In actual processing, the myocardial bridge determination unit 45 determines that the core line voxel surrounded by a plurality of myocardial voxels is a voxel constituting the myocardial bridge region (hereinafter referred to as a bridged voxel), If the voxel is not surrounded by the myocardial voxel, it is determined that the core voxel is not a bridging voxel. More specifically, first, one myocardial voxel is automatically or manually set as the start voxel of the region growth process within the orthogonal cross section of the blood vessel core line, and voxels having voxel values of the myocardial region are integrated one after another. . It is determined based on the shape of the integrated region whether the integrated region (myocardial region) after the region growth process forms a closed curve outside the core voxel in the orthogonal cross section of the blood vessel core line. When the integrated region forms a closed curve outside the core voxel, it is determined that the core voxel is a bridging voxel. The bridge voxel is flagged as a myocardial bridge. On the other hand, when the integrated region does not form a closed curve outside the blood vessel region, it is determined that the core voxel is not an overhead voxel. The bridge voxel is flagged as a myocardial bridge. The myocardial bridge determination unit 45 performs this determination process for all the core voxels.

  FIG. 6 is a diagram showing a bridging voxel 63A that is flagged and a normal core voxel 63B that is not flagged. When the determination process by the myocardial bridge determination unit 45 is completed, as shown in FIG. 6, for each core wire voxel 63, the bridge voxel 63A or the normal core wire voxel 63B is determined.

  Thereafter, as shown in FIG. 7, when a predetermined number or more of the bridging voxels 63 </ b> A continue, the myocardial bridging determination unit 45 sets the blood vessel region in the range of the plurality of consecutive bridging voxels 63 </ b> A as the myocardial bridging region 62 </ b> A. This predetermined number can be arbitrarily set by the user via the input unit 3 or the like. Hereinafter, the setting process of the myocardial bridge region 62A by the myocardial bridge determination unit 45 will be described in detail. First, a plurality of bridging voxels 63A that are continuous for a predetermined number or more are traced to identify the overhead voxels at both ends of the plural bridging voxels 63A. Both end surfaces that include the identified overhead line voxels at both ends and are orthogonal to the core line are set. Then, the blood vessel region sandwiched between the set both end faces is set as the myocardial bridging region 62A. A flag indicating that myocardial cross-linking is set is set in the myocardial cross-linking region 62A. The position information of the myocardial bridge region 62A is stored in the storage unit 2.

  In addition, the setting method of a myocardial bridge | crosslinking area | region is not limited only to the said method. For example, the blood vessel region in the range of all the overhead voxels may be set as the myocardial bridge region.

  The myocardial bridge determination unit 45 may determine the blood vessel region as a myocardial bridge region only when the blood vessel region is surrounded by a myocardial region having a predetermined thickness or more in the orthogonal cross section of the blood vessel core line. This predetermined thickness can be arbitrarily set by the user via the input unit 3 or the like.

  When it is determined that the myocardial bridge region is included (step SA7: YES), the control unit 7 sends the myocardial bridge region to the myocardial bridge position calculation unit 46, the myocardial bridge length calculation unit 47, and the myocardial bridge thickness calculation unit 48. The position, length, and thickness are calculated.

  In the position calculation process, the myocardial bridge position calculating unit 46 calculates the position of the myocardial bridge area (step SA8). The position is defined as the length of the blood vessel core line from the reference point of the blood vessel region to the myocardial bridge region. The reference point of the blood vessel region is, for example, the left coronary artery input portion of the coronary arteries. Specifically, the myocardial bridge position calculating unit 46 calculates the length of the blood vessel core line from the voxel closest to the left coronary artery input part to the left coronary artery input part among the voxels constituting the myocardial bridge. Typically, the length of the blood vessel core line is calculated based on the number of core line voxels.

  In the length calculation process, the myocardial bridge length calculation unit 47 calculates the length of the myocardial bridge region (step SA8). The length is defined as the length of the blood vessel core line included in the myocardial bridge region. Specifically, the myocardial bridge length calculation unit 47 counts the core voxels included in the myocardial bridge region, and calculates the path length of the blood vessel core line in the myocardial bridge region based on the counted value.

  In the thickness calculation processing, the myocardial cross-linking thickness calculation unit 48 calculates the thickness of the myocardial cross-linking region (step SA8). There are multiple patterns in the definition of thickness. For example, there are the following three patterns.

  As shown in FIG. 8, the first thickness is defined as the radius of a sphere 65 that is inscribed in the outer wall surface 64 of the myocardial region with each core voxel included in the myocardial bridging region 62A as the center.

  As shown in FIG. 9, the second thickness is defined as a point P1 intersecting with the heart outer wall surface 64 and a point P2 intersecting with the blood vessel outer wall surface 65 on a straight line A2 orthogonal to the long axis A1 of the heart and passing through the core wire. Defined as the distance between. Specifically, the myocardial cross-linking thickness calculation unit 48 first approximates the heart region to an ellipsoid and calculates the major axis A1 of the ellipsoid. The myocardial bridge thickness calculating unit 48 calculates the second thickness of each core voxel included in the myocardial bridge region 62A according to the above-described definition of the second thickness.

  As shown in FIG. 10, the third thickness is between a point P4 that intersects the outer heart wall surface 64 and a point P5 that intersects the outer blood vessel wall surface 65 on a straight line A3 passing through the center P3 and the core wire 63 of the heart region. Stipulated as the distance. Specifically, the myocardial bridge thickness calculation unit 48 first approximates the heart region to an ellipsoid and calculates the center position P3 of the heart. This center position P3 is defined by, for example, the intersection of the major axis A1 and the minor axis A4 of the ellipsoid. Next, the myocardial bridge thickness calculating unit 48 calculates the third thickness of each core voxel included in the myocardial bridge region 62A according to the above-described definition of the third thickness.

  When calculating the thickness of the myocardial region for each myocardial voxel, the myocardial bridge thickness calculating unit 48 specifies the maximum thickness and the position of the calculated thickness.

  When the position, length, and thickness of the myocardial bridge region are calculated, the control unit 7 causes the image generation unit 5 to perform image generation processing. In the image generation process, the image generation unit 5 generates display image data including the myocardial bridge region from the volume data set (step SA9). Specifically, the image generation unit 5 calculates the line-of-sight direction in which the myocardial bridge region can be seen based on the position of the blood vessel core line and the position of the myocardial bridge region. Then, the image generation unit 5 generates CPR image and SVR image data from the volume data set based on the calculated line-of-sight direction.

  When the display image data is generated, the control unit 7 causes the display unit 6 to perform the first display process. In the first display process, the display unit 6 displays the generated display image in a predetermined display layout (step SA10). The display unit 6 displays quantitative numerical values such as the position, length, and thickness calculated together with the display image as character information. The display conditions such as the display layout of images and character information, the image type such as CPR image and SVR image, the color, size and position of each character information, and the presence / absence of display can be set via the input unit 3. is there.

  FIG. 11 is a diagram showing a display layout example of the display screen displayed in step SA10. As shown in FIG. 11, the display unit 6 displays a CPR image, an SVR image, and character information indicating the position, length, and thickness of the myocardial bridge. The CPR image has a good list of blood vessels. SVR images show good anatomical features with no distortion in shape, size, and positional relationship.

  On the other hand, when the myocardial bridge determination unit 45 determines that there is no myocardial bridge region (step SA7: NO), the control unit 7 causes the display unit 6 to perform the second display process. In the second display process, the display unit 6 displays a message indicating that the myocardial bridging region is not included in the blood vessel region (step SA11).

  This completes the myocardial bridging diagnostic imaging process according to the first embodiment.

  According to the above configuration, the image processing apparatus 1 automatically determines the presence or absence of a myocardial bridge region in a volume data set generated by an X-ray computed tomography apparatus or a magnetic resonance imaging apparatus, and displays the determination result. When there is a myocardial cross-linking region, the image processing apparatus 1 performs quantitative evaluation represented by the position, length, thickness, and the like of the myocardial cross-linking region and displays the evaluation result. Thus, according to the first embodiment, it is possible to reduce labor and time related to diagnostic imaging of myocardial bridge.

  The image processing apparatus 1 may be a computer apparatus for performing image diagnosis, examination, or observation, or may be incorporated in a medical image diagnosis apparatus such as an X-ray computed tomography apparatus or a magnetic resonance imaging apparatus. good.

(Second Embodiment)
Since blood vessels are compressed by the myocardium at the site of myocardial cross-linking, changes in blood flow due to Milking may be observed. At the site where milking occurs, blood flow from the myocardial bridge to the ascending side and an increase in blood flow velocity to the descending side occur during systole. In addition, the myocardial cross-linking blood vessel is compressed by the myocardium during the systole, so that stenosis may occur temporarily. Therefore, it is clinically meaningful to compare stenosis rates calculated at different time phases. An image processing apparatus according to the second embodiment of the present invention analyzes hemodynamics of a blood vessel region included in a volume data set related to a plurality of time phases generated by a magnetic resonance imaging apparatus, and displays the analysis result. is there.

  Hereinafter, a second embodiment of the present invention will be described. In the following description, components having substantially the same functions as those of the present embodiment are denoted by the same reference numerals, and redundant description will be given only when necessary. FIG. 12 is a diagram showing the configuration of the image processing apparatus 20 according to the second embodiment of the present invention. As illustrated in FIG. 12, the image processing apparatus 20 includes a storage unit 2, an input unit 3, an image processing unit 4, an image generation unit 5, a display unit 6, and a control unit 7.

  The storage unit 2 stores a plurality of volume data sets related to a plurality of time phases generated by a magnetic resonance imaging apparatus using an MRA (MR Angiography) method. MRA is a blood flow analysis method in a magnetic resonance imaging apparatus. MRA is an imaging method in which only a blood vessel is imaged using the fact that components of an MR signal derived from a stationary substance and an MR signal derived from blood flow are different. One of the pulse sequence methods peculiar to this MRA is a PC (Phase Contrast) method. The blood flow velocity information can be imaged by the PC method. That is, the storage unit 2 stores a plurality of volume data sets related to a plurality of time phases generated using the PC method by the magnetic resonance imaging apparatus.

  The image processing unit 4 reads the volume data set relating to the specific time phase input by the input unit 3 from the storage unit 2 and performs various image processing for determining the presence or absence of myocardial bridging and evaluating myocardial bridging. . Furthermore, the image processing unit 4 performs blood flow analysis based on a plurality of volume data sets, determines the presence or absence of stenosis in the myocardial bridge region, and calculates the stenosis rate. Specifically, the image processing unit 4 includes a myocardial specifying unit 41, a blood vessel specifying unit 42, a segmentation unit 43, a core specifying unit 44, a myocardial bridge determination unit 45, a myocardial bridge position calculating unit 46, and a myocardial bridge length calculating unit 47. In addition to the myocardial cross-linking thickness calculation unit 48, a blood flow analysis unit 49 and a stenosis analysis unit 50 are included. The blood flow analysis unit 49 performs blood flow analysis on a plurality of volume data sets related to a plurality of time phases. The stenosis analysis unit 50 analyzes the stenosis state of the myocardial bridge region.

  Next, myocardial bridging image diagnosis processing performed under the control of the control unit 7 will be described. FIG. 13 is a diagram showing a typical flow of diagnostic imaging processing for myocardial cross-linking.

  It is assumed that a plurality of volume data sets related to a plurality of time phases generated by using the PC method by a magnetic resonance imaging apparatus or the like are stored in the storage unit 2 before step SB1.

  At the start of the myocardial cross-linking image diagnosis process, the control unit 7 waits for information related to the time phase of the volume data set to be processed (step SB1).

  The control unit 7 causes the myocardial specifying unit 41 to perform myocardial specifying processing when the user inputs information related to the time phase via the input unit 3 (step SB1: YES). In the myocardial specifying process, the myocardial specifying unit 41 reads the input volume data set related to the time phase from the storage unit 2 and specifies the myocardial region included in the read volume data set (step SB2).

  Moreover, the control part 7 makes the blood-vessel specific | specification part 42 perform a blood-vessel specific process triggered by the information regarding a time phase being input via the input part 3 by a user (step SB1: YES). In the blood vessel specifying process, the blood vessel specifying unit 42 reads the input volume data set related to the time phase from the storage unit 2 and specifies the blood vessel region included in the read volume data set (step SB3).

  When the blood vessel region is specified, the control unit 7 causes the segmentation unit 43 to perform segmentation processing. In the segmentation process, the segmentation unit 43 segments each of the plurality of portions constituting the blood vessel region for each classification name (step SB4).

  When the blood vessel region is segmented, the control unit 7 causes the core line specifying unit 44 to perform the core line specifying process. In the core line specifying process, the core line specifying unit 44 specifies the core line of the segmented blood vessel region (step SB5).

  When the myocardial region and the blood vessel core line are specified, the control unit 7 causes the myocardial bridge determination unit 45 to perform determination processing. In the determination process, the myocardial bridge determination unit 45 determines whether or not the blood vessel region includes the myocardial bridge region based on the voxel values of a plurality of voxels surrounding the blood vessel region (step SB6).

  When it is determined that the myocardial bridge region is included (step SB7: YES), the control unit 7 sends the myocardial bridge position calculation unit 46, myocardial bridge length calculation unit 47, and myocardial bridge thickness calculation unit 48 to the myocardial bridge position. The calculation processing of the position, length, and thickness of the area is performed. In the position calculation process, the myocardial bridge position calculating unit 46 calculates the position of the myocardial bridge area (step SB8). In the length calculation process, the myocardial bridge length calculation unit 47 calculates the length of the myocardial bridge region (step SB8). In the thickness calculation process, the myocardial cross-linking thickness calculation unit 48 calculates the thickness of the myocardial cross-linking region (step SB8).

  When the position, length, and thickness of the myocardial bridge region are calculated, the control unit 7 causes the blood flow analysis unit 49 to perform blood flow analysis processing. In the blood flow analysis process, the blood flow analysis unit 49 reads a plurality of volume data sets related to a plurality of time phases including the specific time phase input in step SA1, performs image processing on the read plurality of volume data sets, and performs blood processing. A flow analysis is performed (step SB9). Specifically, the difference between the voxel values of the same anatomical part included in the volume data set relating to the specific time phase and the other volume data set is calculated. This same portion is automatically or manually designated, and is, for example, a blood vessel region specified in step SB3. Each difference value calculated in each voxel corresponds to a change in blood flow velocity in each voxel. Based on this difference value, a region in which blood is flowing backward is specified in the blood vessel region. The reverse flow region is, for example, a region where the blood flow is directed upward from the myocardial bridge region. The blood flow velocity information is stored in the storage unit 2. Further, the position information of the backflow region is also stored in the storage unit 2.

  When blood flow analysis is performed, the control unit 7 causes the stenosis analysis unit 50 to perform stenosis analysis processing. In the stenosis analysis process, the stenosis analysis unit 50 analyzes the stenosis state of the myocardial bridge region (step SB10). More specifically, the stenosis analysis unit 50 determines the presence or absence of stenosis in the myocardial bridge region, and calculates the stenosis rate. These stenosis analyzes are performed in each cross section set in step SB5 (step SA5) in order to determine the myocardial bridge region, that is, in each orthogonal cross section set in the blood vessel core line. A method for determining the presence or absence of stenosis and a method for calculating the stenosis rate are performed using known methods. For example, the stenosis rate is calculated based on the cross-sectional area or blood vessel diameter of the myocardial bridging region in the orthogonal cross section.

  When the stenosis analysis is performed, the control unit 7 causes the image generation unit 5 to perform image generation processing. In the image generation process, the image generation unit 5 generates display image data including the myocardial bridge region from the volume data set (step SB11). The image generation unit 5 generates morphological image data such as an SVR image and a CPR image based on the volume data set. The image generator 5 generates functional image data representing hemodynamics. The functional image is generated by assigning the blood flow velocity and direction calculated in step SB9 to each pixel. The cross section of the generated morphological image and the cross section of the functional image are the same cross section.

  When the display image data is generated, the control unit 7 causes the display unit 6 to perform the third display process. In the third display process, the display unit 6 highlights and displays the backflow region included in the generated display image (step SB12). Specifically, the display unit 6 aligns and displays the morphological image generated in step SB11 and the function image.

  FIG. 14 is a diagram showing a display layout example of the display screen displayed in step SB12. As shown in FIG. 14, the display unit 6 explicitly displays the backflow region identified in step SB9 on the CPR image or SPR image. The display unit 6 displays the maximum stenosis rate calculated in step SB10 as character information. At this time, the display unit 6 may explicitly display the position of the maximum stenosis rate, for example, the cross section where the maximum stenosis rate is calculated.

  On the other hand, when it is determined in step SB7 that there is no myocardial bridge region (step SB7: NO), the control unit 7 causes the display unit 6 to perform the second display process. In the second display process, the display unit 6 displays a message indicating that the myocardial bridge region is not included in the blood vessel region (step SB13).

  Thus, the myocardial bridging diagnostic imaging process according to the second embodiment is completed.

  Thus, according to the second embodiment, it is possible to reduce labor and time related to diagnostic imaging of myocardial bridge.

(Modification of the second embodiment)
The image processing apparatus according to the modification of the second embodiment analyzes the hemodynamics of the blood vessel region included in the volume data set related to a plurality of time phases generated by the X-ray computed tomography apparatus, and displays the analysis result. Is. Hereinafter, an image processing apparatus according to a modification of the second embodiment will be described. In the following description, components having substantially the same functions as those of the first embodiment or the second embodiment are denoted by the same reference numerals, and redundant description is provided only when necessary.

  In step SB9 of FIG. 13, the blood flow analysis unit 49 according to the modification of the second embodiment calculates the blood flow velocity in the blood vessel region extracted in step SB3 based on the difference between the volume data sets regarding a plurality of time phases. To do. More specifically, the blood flow analysis unit 49 specifies the start position of the contrast region in the coronary artery of the myocardial bridge based on the pixel value of the contrast region for each of two temporally adjacent volume data sets. . Then, the blood flow analysis unit 49 calculates the blood flow velocity from the movement amounts of the two specified head positions and the time intervals between the two volume data sets.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a diagram showing a configuration of an image processing apparatus according to a first embodiment of the present invention. The figure which shows the typical flow of the image diagnosis process of the myocardial bridge | bridging performed under control of the control part of FIG. FIG. 3 is a supplementary diagram of step SA5 in FIG. 2. FIG. 3 is a supplementary view of step SA6 of FIG. FIG. 3 is a supplementary view of step SA6 of FIG. FIG. 3 is a supplementary view of step SA6 of FIG. FIG. 3 is a supplementary view of step SA6 of FIG. The figure which shows the 1st thickness calculated in step SA8 of FIG. The figure which shows the 2nd thickness calculated in step SA8 of FIG. The figure which shows the 3rd thickness calculated in step SA8 of FIG. The figure which shows the example of a display layout of the display screen displayed in step SA10 of FIG. The figure which shows the structure of the image processing apparatus concerning 2nd Embodiment of this invention. The figure which shows the typical flow of the image diagnosis process of the myocardial bridge | bridging performed under control of the control part of FIG. It is a figure which shows the example of a display layout of the display screen displayed in step SB12 of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 2 ... Memory | storage part, 3 ... Input part, 4 ... Image processing part, 5 ... Image generation part, 6 ... Display part, 7 ... Control part, 41 ... Myocardial specific part, 42 ... Blood vessel specific part, DESCRIPTION OF SYMBOLS 43 ... Segmentation part, 44 ... Core wire specific | specification part, 45 ... Myocardial bridge determination part, 46 ... Myocardial bridge position calculation part, 47 ... Myocardial bridge length calculation part, 48 ... Myocardial bridge thickness calculation part

Claims (7)

A storage unit for storing a volume data set relating to the heart of the subject;
A blood vessel specifying unit for specifying a blood vessel region included in the volume data set;
A determination unit that determines whether or not the vascular region includes a myocardial bridging region based on a voxel value of a plurality of voxels surrounding the vascular region;
A display unit for displaying information on a determination result by the determination unit;
An image processing apparatus comprising: An image generator for generating display image data including at least a portion of the myocardial bridge region based on the volume data set;
The display unit displays the generated display image and the determination result;
The image processing apparatus according to claim 1. A first calculator that calculates the position, length, and thickness of the myocardial bridge region;
The display unit displays the calculated position, length, and thickness;
The image processing apparatus according to claim 1. A second calculation unit for calculating a stenosis rate based on a cross-sectional area or a blood vessel diameter of the myocardial cross-linking region,
The display unit displays the calculated stenosis rate.
The image processing apparatus according to claim 1. A storage unit that stores a plurality of volume data sets related to a plurality of time phases with respect to the heart of the subject;
A blood vessel specifying unit for specifying a blood vessel region included in a specific volume data set specified in accordance with an instruction from a user among the plurality of volume data sets;
A determination unit that determines whether or not the vascular region includes a myocardial bridging region based on a voxel value of a plurality of voxels surrounding the vascular region;
A display unit for displaying information on a determination result by the determination unit;
An image processing apparatus comprising: A blood flow analysis unit that calculates a change in blood flow velocity of the blood vessel region included in each of the plurality of volume data sets;
The display unit displays information regarding the change in the calculated blood flow velocity.
The image processing apparatus according to claim 5. An image generator for generating display image data including at least a portion of the myocardial bridging region based on the specific volume data set;
The blood flow analysis unit identifies, from the blood vessel region, a reverse flow region in which blood flows backward based on the change in the calculated blood flow velocity.
The display unit highlights and displays the backflow region in the generated display image.
The image processing apparatus according to claim 6.

Images