JP5491729B2 - Image processing apparatus and stenosis analysis program - Google Patents

Description

  The present invention relates to an image processing apparatus and a stenosis state analysis program for evaluating a stenosis rate of a blood vessel.

  The heart has a coronary artery that runs coronally around it. The constriction of the coronary artery can be considered as permanent stenosis or temporary stenosis. A typical cause of permanent stenosis is a soft plaque adhering to the inside of a blood vessel. A typical cause of temporary stenosis is myocardial bridging that causes abnormal blood flow in the artery and myocardial ischemia due to compression of the coronary artery during systole.

With the recent development of medical image collection technology, pseudo-periodic data of the heart is created by combining the data related to different periods from the time-series data collected by the image diagnostic device using the periodicity of the heart motion. It became possible. Further, Patent Literature 1 is disclosed as a technique for calculating a stenosis rate of a blood vessel. However, there is no display method for presenting a stenosis state over a plurality of time phases in an easily understandable manner to the user. There is also no display method for simply presenting images of time phases and blood vessel cross-sectional positions expected by the user. For this reason, the accuracy and efficiency of image diagnosis in a stenotic state is not improved as compared with the degree of development of medical image collection technology.
JP 2007-283373 A

  An object of the present invention is to provide an image processing apparatus and a stenosis rate analysis program that can improve accuracy and efficiency of image diagnosis in a stenosis state.

An image processing apparatus according to a first aspect of the present invention includes a storage unit that stores a plurality of volume data sets relating to a plurality of time phases, an extraction unit that extracts a blood vessel region from each of the plurality of volume data sets, and the extraction A calculation unit for calculating an index value indicating a degree of stenosis based on the shape of the blood vessel region for each of a plurality of cross sections substantially orthogonal to the core line of the blood vessel region, and an analysis for analyzing the calculated index value in time series And a display unit for displaying an analysis result of the time series analysis , wherein the analysis unit shows a clinically characteristic value among the calculated index values Based on the time phase / position specifying part for specifying the time phase and the cross-sectional position of the cross section, and the time phase and the cross-sectional position of the specified cross section, the time phase and the cross-sectional position where the stenosis is generated are two-dimensional Raw map shown above And, and a generation unit for outputting map said generated as a result of the analysis, characterized in that.

The stenosis state analysis program according to the second aspect of the present invention provides a computer with an extraction function for extracting a blood vessel region from each of a plurality of volume data sets relating to a plurality of time phases, and substantially orthogonal to the core line of the extracted blood vessel region. A calculation function for calculating an index value representing vascular properties based on a shape of the blood vessel region, an analysis function for analyzing the calculated index value in time series, and an analysis of the time series analysis A stenosis analysis program for realizing a display function for displaying a result , wherein the analysis function includes a time phase and a cross-sectional position of a cross-section indicating a clinically characteristic value of the calculated index values Based on the time phase / position specifying function for specifying the cross-section, and the time phase and cross-sectional position of the specified cross-section, a map representing the time phase and cross-sectional position where the stenosis occurred on a two-dimensional plane is generated. , And a generation function of outputting the map said generated as a result of the analysis, characterized in that.

  According to the present invention, it is possible to provide an image processing apparatus and a stenosis state analysis program that can improve accuracy and efficiency of image diagnosis in a stenosis state.

  Hereinafter, an image display apparatus and a stenosis state analysis program according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an image processing apparatus 1 according to an embodiment of the present invention. As shown in FIG. 1, the image processing apparatus 1 includes a processing data storage unit 10, a blood vessel extraction unit 12, a same blood vessel association unit 14, a stenosis index value calculation unit 16, a stenosis index value analysis unit 18, a display control unit 20, and a display. Unit 22, operation unit 24, program storage unit, and system control unit 28. The image processing apparatus 1 is typically a computer for image processing.

  The processing data storage unit 10 stores a plurality of volume data sets relating to a plurality of time phases generated by a multi-slice type X-ray computed tomography apparatus. Each of the stored multi-phase volume data sets relates to the heart of a subject suspected of having a stenosis in the coronary artery. These multiple time phase volume data sets are time series data for reproducing at least one heartbeat of the subject's heart.

  The blood vessel extraction unit 12 extracts a plurality of time phase blood vessel regions from a plurality of time phase volume data sets by threshold processing or the like. This embodiment can be applied to any extracted blood vessel region relating to a blood vessel in any part. However, in order to specifically describe the following, it is assumed that the extracted blood vessel region relates to a coronary artery in which an effect specific to the present embodiment is particularly likely to appear.

  The same blood vessel association unit 14 associates anatomically identical portions between the extracted coronary artery regions of a plurality of time phases.

  The stenosis index value calculation unit 16 calculates an index value indicating the degree of stenosis (hereinafter referred to as a stenosis index value) for each of a plurality of orthogonal sections (sections orthogonal to the blood vessel core line) set in each coronary artery region. To do. As a result, for each time phase (each volume data set), a graph indicating the stenosis index value that changes according to the position on the coronary artery region (hereinafter referred to as a stenosis index value graph) is calculated. The stenosis index value is calculated based on the shape of the blood vessel region on the orthogonal cross section. The stenosis index value is a blood vessel diameter or cross-sectional area of a blood vessel region on an orthogonal cross section, a stenosis rate, or the like.

  The stenosis index value analysis unit 18 performs time series analysis on the calculated stenosis index value. Specifically, the stenosis index value analysis unit 18 includes a stenosis section specifying unit 181 and a stenosis map generation unit 182. The stenosis region specifying unit 181 specifies a stenosis index value having a clinically characteristic value from a plurality of stenosis index values, and determines the cross-sectional position and time phase of the orthogonal cross section where the specified stenosis index value is calculated. Identify. This range of clinically distinct values varies depending on the type of stenosis index value. The cross-sectional position of the orthogonal cross section for which the stenosis index value within this range is calculated is the position of the stenosis site. The stenosis map generation unit 182 maps the position and time phase of the specified stenosis site on a two-dimensional plane, and generates a stenosis index value map (hereinafter referred to as a stenosis map). The generated stenosis map shows a time phase and a cross-sectional position at which a stenosis site is generated.

  The display control unit 20 displays the result of the time series analysis on the display unit 22. Specifically, the display control unit 20 displays a stenosis map on the display unit 22. As the display unit 22, for example, a display device such as a CRT display, a liquid crystal display, an organic EL display, or a plasma display can be used as appropriate.

  The operation unit 24 receives various commands and information input from the operator. As the operation unit 24, a pointing device such as a mouse or a trackball, a selection device such as a mode change switch, or an input device such as a keyboard can be used as appropriate.

  The program storage unit 26 stores a stenosis state analysis program for a stenosis state analysis process described later.

  The system control unit 28 reads out the stenosis state analysis program stored in the processing data storage unit 10, develops it on the memory, and controls each unit of the image processing apparatus 1, thereby controlling the stenosis state analysis process unique to the present embodiment. Execute.

  FIG. 2 is a diagram showing a typical flow of a stenosis state analysis process performed under the control of the system control unit 28.

  When the user gives an instruction to start the stenosis analysis process via the operation unit 24, the system control unit 28 starts the process. First, the system control unit 28 reads a volume data set having a plurality of time phases from the processing data storage unit 10 (step SA1). The read multiple volume data sets are supplied to the blood vessel extraction unit 12 by the system control unit 28.

  When the supply of volume data sets of a plurality of time phases is completed, the system control unit 28 causes the blood vessel extraction unit 12 to perform coronary artery extraction processing. In the extraction process, the blood vessel extraction unit 12 extracts a plurality of time phase coronary artery regions from a plurality of time phase volume data sets. Specifically, first, the blood vessel extraction unit 12 automatically specifies the base of the coronary artery region based on the shape of the heart region included in the volume data set. Then, the blood vessel extraction unit 12 automatically extracts a coronary artery region connected to the base using the identified base as a starting point using a coronary artery search engine. This extraction process is performed for all volume data sets read in step SA1. Therefore, a plurality of time-phase coronary artery regions are extracted by the extraction process. The extracted coronary artery region data is supplied to the same blood vessel association unit 14 by the system control unit 28.

  When the coronary artery region is extracted, the system control unit 28 causes the same blood vessel association unit 14 to perform association processing of the same part of the coronary artery region. In the association processing, the same blood vessel association unit 14 associates anatomically identical parts between the extracted coronary artery regions of a plurality of time phases (step SA3). Specifically, the same blood vessel association unit 14 identifies a plurality of anatomical feature points included in each of a plurality of time-phase coronary artery regions. Next, the same blood vessel association unit 14 generates data of the coronary artery tree based on the plurality of identified feature points for each of the plurality of time phase coronary artery regions. Then, the same blood vessel association unit 14 associates anatomically identical parts included in the coronary artery regions of the plurality of time phases using the generated coronary artery tree of the plurality of time phases.

  FIG. 3 is a diagram illustrating an example of the structure of the coronary artery region. As shown in FIG. 3, the coronary artery region CA is divided into a starting point (base portion) s1 that is an end point on the aorta side, a plurality of end points e1, e2, e3, and e4 that are other end points on the coronary artery region CA, and two directions. It has a plurality of anatomical feature points such as a plurality of branch points n1, n2, and n3. In the feature point identification process, the same blood vessel association unit 14 identifies feature points such as the start point s1, the end points e1, e2, e3, e4, and the branch points n1, n2, n3. More specifically, the same blood vessel association unit 14 traces the coronary artery region CA from the start point s1 designated automatically or by the user via the operation unit 24, and branches n1, n2, n3 and end points e1, e2, e3 and e4 are specified. Once the feature points are identified, coronary tree data is generated.

  FIG. 4 is a diagram illustrating an example of a coronary artery tree related to the coronary artery region in FIG. 3. As shown in FIG. 4, the coronary artery tree is composed of coronary artery path information and feature point coordinate information. The coronary artery route information indicates the route of the coronary artery region from the start point to each end point via a plurality of branch points. The coronary artery path is identified by tracing the coronary artery region from the start point to each end point. In FIG. 4, path 1: start point s 1 → branch point n 1 → branch point n 2 → end point e 1, path 2: start point s 1 → branch point n 1 → branch point n 2 → branch point n 3 → end point e 2, path 3: start point s 1 → branch point n1.fwdarw.branch point n2.fwdarw.branch point n3.fwdarw.end point e3, and path 4: Four paths of start point s1.fwdarw.branch point n1.fwdarw.end point e4 are shown. The feature point coordinate information indicates the coordinates of the start point s1, the end points e1, e2, e3, e4, and the branch points n1, n2, n3. When the data of the coronary artery tree is generated, the same part of the coronary artery region, that is, the same path is associated.

  FIG. 5 is a diagram for explaining the association processing. As shown in FIG. 5, for example, the correlating process is performed by, for example, a coronary artery tree of a time phase (t1) to be processed (hereinafter referred to as a reference tree) and a coronary artery of the next time phase (t1 + Δt). This is performed using a tree (hereinafter referred to as a comparison tree). First, the degree of coincidence between one of a plurality of coronary artery paths constituting the reference tree and all the coronary artery paths constituting the comparison tree is calculated. Assume that the coronary artery paths of the reference tree having the minimum coincidence among all the calculated degrees of coincidence and the coronary artery paths of the comparison tree are anatomically identical, and the coronary artery paths are associated with each other. In this way, association is performed for all coronary artery paths in the reference tree. This association process is performed for all volume data sets.

  A specific method for calculating the degree of coincidence will be specifically described by taking the coronary artery path 1 of the reference tree as an example. First, the distance between the start point of the coronary artery path 1 of the reference tree and the start point of the coronary artery path 1 of the comparison tree, the distance between the end point of the coronary artery path 1 of the reference tree and the end point of the coronary artery path 1 of the comparison tree, and the coronary artery path 1 of the reference tree And the branch point of the coronary artery path 1 of the comparison tree is calculated. Here, the “distance” is a geometric distance between points in the volume data. When the distance between each point is calculated, the total value of the calculated distance is calculated. Similarly, the distances between the start point, end point, and branch point of the coronary artery path 1 of the reference tree and the start point, end point, and branch point of the coronary artery path 2 of the reference tree are calculated, and the total value of the distances is calculated. Similarly, the coronary artery path 1 of the reference tree and the coronary artery path 2 of the comparison tree, the coronary artery path 1 of the reference tree and the coronary artery path 3 of the comparison tree, and the coronary artery path 1 of the reference tree and the coronary artery path 4 of the comparison tree are the same. The distance between the start points, the end points, and the branch points is calculated, and the total value is calculated. Then, a minimum value is specified from a plurality of total values, and a combination of coronary artery paths having the specified minimum value is regarded as being anatomically identical and associated.

  When the association is performed, the system control unit 28 causes the stenosis index value calculation unit 16 to calculate the lumen cross-sectional area. In the lumen cross-sectional area calculation process, the stenosis index value calculation unit 16 sets a plurality of orthogonal sections for each of a plurality of time-phase coronary artery areas, and the area of the lumen of the coronary artery region on the set plurality of orthogonal sections (Luminous cross-sectional area) is calculated (step SA4). The method for calculating the lumen cross-sectional area is a known technique disclosed in, for example, Patent Document 1, and thus the description thereof is omitted. Note that the lumen cross-sectional area calculation process is performed for each coronary artery path. The calculated lumen cross-sectional area is stored in the processing data storage unit 10 in association with the coronary artery path identification number data and time phase data.

  When the lumen cross-sectional area is calculated, the system control unit 28 causes the stenosis index value calculation unit 16 to calculate the cross-sectional area of the virtual normal blood vessel wall. In the calculation processing of the cross-sectional area of the virtual normal blood vessel wall, the stenosis index value calculation unit 16 estimates the virtual normal blood vessel region for each of the plurality of time-phase coronary artery regions, and performs virtual normal on the orthogonal cross section of the estimated virtual normal blood vessel region. The area within the closed curve formed by the blood vessel wall (the cross-sectional area of the virtual normal blood vessel wall) is calculated (step SA5). Since the method for calculating the cross-sectional area of the virtual normal blood vessel wall is a known technique disclosed in Patent Document 1, for example, description thereof is omitted. The calculation process of the cross-sectional area of the virtual normal blood vessel wall is performed for each coronary artery path. The calculated cross-sectional area of the virtual normal blood vessel wall is stored in the processing data storage unit 10 in association with the data of the identification number of the coronary artery path and the data of the time phase.

  When the cross-sectional area of the virtual normal blood vessel wall is calculated, the system control unit 28 causes the stenosis index value calculation unit 16 to perform stenosis rate calculation processing. In the stenosis rate calculation process, the stenosis index value calculation unit 16 calculates the stenosis rate based on the lumen cross-sectional area calculated in step SA4 and the virtual normal blood vessel wall cross-sectional area calculated in step SA5 (step SA6). ). The stenosis rate is calculated for each orthogonal cross section of the coronary artery region.

  FIG. 6 is a graph showing a stenosis rate (hereinafter, referred to as a stenosis rate graph) that changes according to the position on the coronary artery region (the position of the orthogonal cross section). As shown in FIG. 6, the horizontal axis of the stenosis rate graph is defined as the cross-sectional position, and the vertical axis is defined as the stenosis rate. Here, the cross-sectional position is the distance from the starting point to the orthogonal cross-section on one coronary artery path. Since the calculation method of the stenosis rate is disclosed in, for example, Patent Document 1, description thereof is omitted. The calculated stenosis rate is stored in the processing data storage unit 10 in association with the data of the identification number of the coronary artery path and the data of the time phase.

  When the stenosis rate is calculated, the system control unit 28 causes the stenosis index value analysis unit 18 to perform time series analysis processing of the stenosis index value. In the time series analysis process, the stenosis index value analysis unit 18 performs time series analysis on the stenosis rate calculated in step SA6 and outputs an analysis result (step SA7).

  Hereinafter, the stenosis index value time series analysis process by the stenosis index value analysis unit 18 will be described in detail. In the time-series analysis processing, first, a stenosis site is specified by the stenosis site specifying unit 181 of the stenosis index value analysis unit 18, and then stenosis map data is generated by the stenosis map generation unit 182 of the stenosis index value analysis unit 18. .

  FIG. 7 is a diagram for explaining the stenosis site specifying process by the stenosis site specifying unit 18, and is a diagram illustrating an example of a stenosis rate graph of a plurality of time phases. First, the stenosis region specifying unit 181 reads out the stenosis rates of a plurality of time phases (time phase A to time phase B to time phase C) related to the same coronary artery path from the storage unit 10. When the stenosis rate is read, the stenosis site specifying unit 181 determines whether or not the stenosis rate is within a predetermined range Th set in advance for each orthogonal cross section of the coronary artery region. The predetermined range Th of the stenosis rate is a range of values expected to have the stenosis rate of the stenosis site. For example, in the stenosis rate graph related to time phase A, the stenosis rate is within the predetermined range Th in the cross-section position range R1. In the stenosis rate graph regarding the time phase B, the stenosis rate is within the predetermined range Th not only in the cross-section position range R1 but also in the cross-section position range R2. As described above, when it is determined that the stenosis rate is within the predetermined range Th, the position of the orthogonal cross section (for example, the cross-sectional position in the range R1 or R2) where the stenosis rate is calculated is specified as the position of the stenosis site. . Similarly, the stenosis site specifying unit 181 specifies the position and time phase of the stenosis site for all coronary artery paths in all time phases. The data of the position of the identified stenosis site is stored in the processing data storage unit 10 in association with the time phase data. Further, the position control data and the temporal data are supplied to the stenosis map generation unit 182 by the system control unit 28. The predetermined range Th is a range derived from experience, and can be arbitrarily set automatically or by the user via the operation unit 24.

  The stenosis map generation unit 182 generates stenosis map data based on the position and time phase of the stenosis site with respect to the same coronary artery path. FIG. 8 is a diagram illustrating an example of the stenosis map I1 generated by the stenosis map generation unit 182. Note that the time phases A, B, and C in FIG. 8 and the time phases A, B, and C in FIG. The stenosis map I1 is a two-dimensional plane in which the vertical axis is defined as the cross-sectional position of the orthogonal cross section and the horizontal axis is defined as the time phase. The stenosis map generation unit 182 maps the position of the stenosis site specified by the stenosis site specification unit 181 on the stenosis map in time series.

  Hereinafter, a procedure for generating a stenosis map will be described using time phase A as a specific example. First, a pixel row (parallel to the vertical axis) on the stenosis map I1 corresponding to the time phase A is specified. Next, the pixel on the stenosis map I1 corresponding to the position of the stenosis site is specified in the specified pixel row. A pixel value “1” is assigned to the identified pixel. On the other hand, a pixel value “0” is assigned to a pixel that does not correspond to the position of the stenosis in the pixel column. The pixel assigned the pixel value “1” and the pixel assigned the pixel value “0” are displayed in different colors on the screen by the display control unit 20. This stenosis map I2 is generated by performing the pixel value assignment processing for all time phases. The generated stenosis ratio map data is supplied to the display control unit 20 by the system control unit 28. The data of the stenosis rate map is stored in the processing data storage unit 10 in association with a code indicating the coronary artery path number.

  When the stenosis map data is generated, the system control unit 28 causes the display control unit 20 to perform display processing. In the display process, the display control unit 20 displays the stenosis map on the display unit 22 (step SA8).

  The stenosis map can represent the part where the stenosis has occurred and the time phase on one two-dimensional plane. As is clinically known, there are two types of stenosis: one derived from plaque and the other derived from myocardial cross-linking. As shown in FIG. 8, stenosis derived from plaque constantly appears in all time phases. On the other hand, stenosis resulting from myocardial cross-linking appears discretely in a specific time phase (typically, systole) as shown in FIG. That is, the user can diagnose that the stenosis at the part where the stenosis mark is shown over all the time phases on the stenosis map is derived from the plaque. In addition, the user can diagnose that the stenosis at the part where the stenosis mark is shown only in a specific time phase on the stenosis map is derived from the myocardial bridge. Thus, by observing one stenosis map, the user can know the temporal change of the stenosis site.

  When the stenosis map is displayed in step SA8, the system control unit 28 ends the stenosis state analysis process.

  Thus, the image processing apparatus and the stenosis state analysis program according to the present embodiment improve the accuracy and efficiency of the image diagnosis in the stenosis state.

  In the above embodiment, the stenosis rate is calculated based on the cross-sectional area of the lumen and the cross-sectional area of the virtual normal blood vessel wall. However, the present embodiment need not be limited to this. For example, the stenosis rate may be calculated based on the blood vessel diameter of the lumen and the blood vessel diameter of the virtual normal blood vessel.

  In the above embodiment, the stenosis site is specified based on the stenosis rate. However, the present embodiment need not be limited to this. For example, the stenosis site may be specified based on the lumen cross-sectional area calculated in step SA4. Moreover, you may specify based on the blood vessel diameter of the above-mentioned lumen | bore.

  Further, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

(Modification 1)
In this embodiment, the stenosis rate is calculated based on the lumen cross-sectional area and the virtual normal blood vessel wall cross-sectional area. However, it is not necessary to limit to this. The image processing apparatus according to the first modification calculates the stenosis rate based on the lumen cross-sectional area and the cross-sectional area of the blood vessel outer wall. Hereinafter, an image processing apparatus according to Modification 1 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. 9 is a diagram illustrating a typical flow of a stenosis state analysis process according to the first modification of the present embodiment. As shown in FIG. 9, steps SA1 to SA4 of the stenosis state analysis process according to Modification 1 are the same as steps SA1 to SA4 of the stenosis state analysis process (FIG. 2) according to the present embodiment. Description is omitted.

  When the lumen cross-sectional area is calculated in step SA4, the system control unit 28 causes the stenosis index value calculation unit 16 to perform processing for calculating the cross-sectional area of the blood vessel outer wall. In the calculation process of the cross-sectional area of the blood vessel outer wall, the stenosis index value calculation unit 16 calculates the area in the blood vessel outer wall of the coronary artery region on the orthogonal cross section (blood vessel outer wall cross-sectional area) on each of the plurality of orthogonal cross sections set in the coronary artery region. Are respectively calculated (step SB5). The blood vessel outer wall is specified by the stenosis index value calculation unit 16 using a known technique. The identified blood vessel outer wall cross-sectional area forms a closed curved surface on the orthogonal cross section. The area within the closed curved surface formed by the blood vessel outer wall is calculated as the blood vessel outer wall cross-sectional area. In addition, the calculation process of the blood vessel outer wall cross-sectional area is performed for each coronary artery path. The calculated blood vessel outer wall cross-sectional area is stored in the processing data storage unit 10 in association with the coronary artery path identification number data and the time phase data.

  When the cross-sectional area of the blood vessel outer wall is calculated, the system control unit 28 causes the stenosis index value calculation unit 16 to perform stenosis index value calculation processing. In the stenosis rate calculation process, the stenosis index value calculation unit 16 calculates a stenosis rate (so-called arterial index) based on the lumen cross-sectional area calculated in step SA4 and the blood vessel outer wall cross-sectional area calculated in step SB5. (Step SB6).

  The processing after step SB6 is the same as that from step SA7 to step SA8 in FIG.

  Thus, the image processing apparatus 1 and the stenosis state analysis program according to the first modification of the present embodiment improve the accuracy and efficiency of image diagnosis in a stenosis state.

(Modification 2)
The image processing apparatus 1 and the stenosis state analysis program according to the present embodiment displayed only a stenosis map. The image processing apparatus 2 and the stenosis state analysis program according to the second modification of the present embodiment display not only a stenosis map but also a display image including a stenosis site. Furthermore, it is also possible to display a mark indicating the time phase of the heartbeat phase, the cross-sectional position of the display image, and the time phase so as to overlap the stenosis map.

  Hereinafter, the image processing apparatus 2 and the stenosis state analysis program according to the second modification of the present embodiment 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. 10 is a diagram illustrating a configuration of the image processing apparatus 2 according to the second modification of the present embodiment. As shown in FIG. 10, the image processing apparatus 2 includes a processing data storage unit 10, a blood vessel extraction unit 12, a same blood vessel association unit 14, a stenosis index value calculation unit 16, a stenosis index value analysis unit 18, a display control unit 20, In addition to the display unit 22, the operation unit 24, the program storage unit 26, and the system control unit 28, an electrocardiogram waveform storage unit 30, an electrocardiographic time phase identification unit 32, and a display image generation unit 34 are provided.

  The electrocardiogram waveform storage unit 30 stores electrocardiogram waveform data of the subject generated by the electrocardiograph. The electrocardiogram waveform is typically obtained by measuring electrical excitation generated from the left ventricle. The electrocardiogram waveform data is transmitted from the electrocardiograph or recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, and is transferred from the recording medium to the electrocardiogram waveform storage unit 30.

  The electrocardiogram time phase specifying unit 32 specifies a time phase of a specific heartbeat phase based on the shape of the electrocardiogram waveform. Examples of the specified heartbeat phase include diastole, systole, end diastole, and end systole.

  The display image generation unit 34 generates display image data by performing three-dimensional image processing on the volume data set. Examples of the three-dimensional image processing include MPR (multi planar reconstruction) processing, CPR (curved planar reconstruction) processing, SPR (streched CPR) processing, volume rendering, surface rendering, MIP (maximum intensity projection), and the like. In addition, as a display image, the MPR image (what is called a Crosscut image) regarding the orthogonal cross section of a coronary artery area | region is suitable. The cross-sectional position, cross-sectional orientation, and time phase of the generated display image can be arbitrarily set by the user via the operation unit 24.

  The display control unit 20 displays a display image side by side in addition to the stenosis map. Furthermore, the display control unit 20 can also display the electrocardiographic waveforms side by side. In addition, the display control unit 20 superimposes a mark indicating the cross-sectional position of the display image (hereinafter referred to as a cross-sectional position mark) and a time phase (hereinafter referred to as a cross-sectional time phase mark) on the stenosis map. Can also be displayed. The display control unit 20 can also display a mark indicating a specific heartbeat phase on the stenosis map.

  FIG. 11 is a diagram illustrating a typical flow of a stenosis state analysis process according to the second modification. As shown in FIG. 11, the stenosis state analysis process according to the modification 2 is a process after step SA7 in FIG.

  When the stenosis map is generated in step SA7, the system control unit 28 causes the electrocardiogram time phase specifying unit 32 to perform end systolic specifying processing. In the end systolic specifying process, the electrocardiogram time phase specifying unit 32 reads the electrocardiographic waveform data stored in the electrocardiogram waveform storage unit 30 and specifies the time phase of the end systole based on the read shape of the electrocardiogram waveform ( Step SC8). For example, the R wave is specified based on the shape of the electrocardiogram waveform, specified, and a certain time after the R wave is specified as the time phase of the end systole. This fixed time differs depending on the subject and is determined according to the time interval between adjacent R waves. The identified end-systolic time phase data is supplied to the display control unit 20 by the system control unit 28.

  When the time phase of the end systole is specified, the system control unit 28 causes the electrocardiogram time phase specifying unit 32 to perform end diastole specifying processing. In the end diastole specifying process, the electrocardiogram time phase specifying unit 32 specifies the end diastole time phase based on the shape of the electrocardiogram waveform (step SC9). End diastole is determined in the same manner as end systole. The time phase data at the end of diastole is supplied to the display control unit 20 by the system control unit 28.

  When the time phase of the end diastole is specified, the system control unit 28 causes the display image generation unit 34 to perform display image generation processing. In the generation process, the display image generation unit 34 generates display image data including at least a part of the stenosis site from the volume data set (step SC10). The cross-sectional position, cross-sectional orientation, and time phase of the display image can be arbitrarily set by the user via the operation unit 26. The generated display image data is supplied to the display control unit 20 by the system control unit 28. Further, both the cross-sectional position data and the time phase data of the display image are supplied to the display control unit 20 by the system control unit 28. A typical example of the display image is an MPR image related to an orthogonal cross section intersecting the stenosis site.

  When the display image data is generated, the system control unit 28 causes the display control unit 20 to perform display processing. In the display process, the display control unit 20 displays the stenosis map and the display image on the display unit 22 (step SC11). Further, the display control unit 20 displays a cross-sectional position mark indicating the cross-sectional position of the display image and a time phase mark indicating the time phase of the display image so as to overlap each other on the corresponding position on the stenosis map. In addition, the display control unit 20 displays an end systole mark indicating the end systole and a mark indicating the end diastole in an overlapping manner at corresponding positions on the stenosis map.

  FIG. 12 is a diagram illustrating an example of a display screen displayed on the display unit 22 under the control of the display control unit 20 in step SC11. As shown in FIG. 12, a display image I2 and a stenosis map I3 are displayed side by side on the display screen. An electrocardiogram waveform I4 is displayed below the stenosis map I3. The stenosis map I3 and the electrocardiogram waveform I4 are arranged so that their time phases are aligned along the horizontal axis. In the stenosis map I3, a sectional position mark M1, a sectional phase mark M2, an end systolic mark M3, and an end diastole mark M4 are displayed in an overlapping manner. The cross-sectional position mark M1 has a linear shape parallel to the horizontal axis (time phase direction) of the stenosis map I2, and is displayed at the cross-sectional position of the display image on the stenosis map I2. The cross-section time phase mark M2 has a linear shape parallel to the vertical axis (cross-section position direction) of the stenosis map I2, and is displayed at the cross-sectional position of the display image on the stenosis map I3. The end systolic mark M3 has a linear shape parallel to the vertical axis of the stenosis map I3, and is displayed at the time phase position of the end systole on the stenosis map I3. The end diastole mark M4 has a linear shape parallel to the vertical axis of the stenosis map I3 and is displayed at the time phase position at the end diastole on the stenosis map I3.

  When the stenosis map and the display image are displayed in step SC11, the system control unit 28 ends the stenosis state analysis process.

  Thus, the display image regarding the stenosis site is displayed along with the stenosis map, so that the user can confirm the stenosis site on the image. In addition, since the cross-section time phase mark is displayed on the stenosis map, the time phase of the display image during one heartbeat can be easily confirmed. In addition, since the cross-sectional position mark is displayed on the stenosis map, the cross-sectional position of the display image from the start point to the end point of the coronary artery region can be confirmed in advance. Also. By displaying the time phase mark of the heartbeat phase on the stenosis map, it is easy for the user to confirm in which time phase the temporary stenosis such as that derived from the myocardial bridge is generated.

  Thus, the image processing apparatus and the stenosis state analysis program according to the second modification of the present embodiment improve the accuracy and efficiency of the image diagnosis in the stenosis state.

  Note that a typical display image generated in step SC10 and displayed in step SC11 is an MPR image related to an orthogonal cross section. However, the present embodiment need not be limited to this. For example, a CPR image or SPR image related to a coronary artery route derived from a stenosis map displayed in parallel may be generated and displayed.

(Modification 3)
The image processing apparatus 2 and the stenosis state analysis program according to the modified example 2 display the cross-section time phase mark on the stenosis map. The image processing apparatus and the stenosis analysis program according to the modified example 3 can change the time phase of the display image and the cross-section time phase mark by the operation unit 24, and interlock the cross-section time phase mark and the time phase of the display image. It is. In the following description, components having substantially the same functions as those of the present embodiment, the first modification, and the second modification are denoted by the same reference numerals, and redundant description is provided only when necessary.

  FIG. 13 is a diagram illustrating a configuration of the image processing apparatus 3 according to the third modification of the present embodiment. As shown in FIG. 13, the image processing apparatus 3 includes a processing data storage unit 10, a blood vessel extraction unit 12, a stenosis index value calculation unit 14, a stenosis state analysis unit 18, a display control unit 20, a display unit 22, an operation unit 24, a program In addition to the storage unit 26, the system control unit 28, the electrocardiogram waveform storage unit 30, the electrocardiogram time phase identification unit 32, and the display image generation unit 34, a display time phase calculation unit 36 is provided.

  The operation unit 24 accepts a change operation of the time phase of the display image (hereinafter referred to as a display time phase) from the user. The display time phase calculation unit 36 calculates the changed display time phase based on the operation amount of the change operation received by the operation unit 24. The display image generation unit 34 generates display image data from the volume data set related to the calculated display time phase after the change. The display control unit 34 moves the cross-section time phase mark to the time phase position on the stenosis map corresponding to the calculated display time phase after the change.

  FIG. 14 is a diagram illustrating a typical flow of a stenosis state analysis program according to the third modification. As shown in the figure, the stenosis state analysis process according to the modification 3 is a process after step SC11 in the figure.

  When the stenosis map and the display image are displayed in step SC11, the system control unit 28 waits for an operation to change the display time phase via the operation unit 24 (step SD12). As the change operation, a mouse operation on a display image, a mouse operation on a stenosis map, an input from a keyboard, or the like can be used. For example, a display phase change operation is performed by performing a wheel operation of the operation unit 24 (mouse) on the display image. As another example, the display time phase may be changed by sliding the cross-section time phase mark on the stenosis map in the horizontal direction via the operation unit 24.

  In response to a change operation performed by the user via the operation unit 24 (step SD12: YES), the system control unit 28 causes the display time phase calculation unit 36 to perform display time phase calculation processing. In the calculation process, the display time phase calculation unit 36 calculates the display time phase after the change based on the operation amount of the change operation received by the operation unit 24 (step SD13). More specifically, the display time phase calculation unit 36 calculates the change amount of the display time phase according to the operation amount, and the calculated change amount and the display time phase of the display image before change displayed in step SD12. Is added to calculate the display time phase after the change. The calculated display time phase data after the change is supplied to the display image generation unit 34 and the display control unit 20 by the system control unit 28.

  When the display time phase after the change is calculated, the system control unit 28 causes the display image generation unit 34 to perform display image generation processing. In the generation process, the display image generation unit 20 reads the volume data set related to the changed display time phase from the processing data storage unit 10, and generates display image data from the read volume data set (step SD14). The cross-sectional position of the generated display image is the same as the cross-sectional position of the display image before the display time phase is changed. The generated display image data is supplied from the system control unit 28 to the display control unit 20.

  When the display image data is generated, the system control unit 28 causes the display control unit 20 to perform display processing. In the display process, the display control unit 20 displays the stenosis map and the display image generated in step SD14 side by side (step SD15). At this time, the display control unit 20 displays the display time phase after the change calculated in step SD13. The time phase position on the stenosis map corresponding to is specified, and the cross-section time phase mark is moved to the specified time phase position. In this manner, the display time phase and the cross-section time phase mark of the display image are updated in conjunction with the change of the display time phase via the operation unit 24.

  When the stenosis map and the display image are displayed in step SD15, the system control unit 28 ends the stenosis state analysis process.

  According to the above configuration, it is possible to change the display time phase of the display image via the operation unit 24 and to move the cross-section time phase mark on the stenosis map. Further, the display time phase can be changed by moving the cross-section time phase mark on the stenosis map via the operation unit 24. Therefore, the stenosis map can also function as a user interface for setting / changing the display time phase.

  Thus, the image processing apparatus 3 and the stenosis state analysis program according to the third modification of the present embodiment realize improvement in accuracy and efficiency of image diagnosis in a stenosis state.

(Modification 4)
The image processing apparatus 2 and the stenosis state analysis program according to the modified example 2 display the cross-section position mark on the stenosis map. The image processing apparatus 4 and the stenosis analysis program according to the modification 4 can change the cross-sectional position and cross-sectional position mark of the display image by the operation unit 24, and link the cross-sectional position mark and the cross-sectional position of the display image. is there. In the following description, components having substantially the same functions as those of the present embodiment, the first modification, the second modification, and the third modification are denoted by the same reference numerals, and will be redundantly described only when necessary.

  FIG. 15 is a diagram illustrating a configuration of the image processing apparatus 4 according to the fourth modification. As shown in FIG. 15, the image processing apparatus 4 includes a processing data storage unit 10, a blood vessel extraction unit 12, a same blood vessel association unit 14, a stenosis index value calculation unit 16, a stenosis state analysis unit 18, a display control unit 20, and a display unit. 22, an operation unit 24, a program storage unit 26, a system control unit 28, an electrocardiogram waveform storage unit 30, an electrocardiogram time phase identification unit 32, and a display image generation unit 34, and a display cross-section position calculation unit 38.

  The operation unit 24 accepts an operation for changing a cross-sectional position (hereinafter referred to as a display cross-sectional position) of a display image from the user. The display cross-section position calculation unit 38 calculates the display cross-section position after the change based on the operation amount of the change operation received by the operation unit 24. The display image generation unit 34 generates display image data from the volume data set based on the calculated changed display cross-sectional position. The display control unit 20 moves the cross-sectional position mark to the cross-sectional position on the stenosis map corresponding to the calculated display cross-sectional position.

  FIG. 16 is a diagram illustrating a typical flow of a stenosis state analysis process according to Modification 4. As shown in FIG. 16, the stenosis state analysis process according to the modification 4 is a process after step SC11 in FIG.

  When the stenosis map and the display image are displayed in step SC11, the system control unit 28 waits for an operation for changing the display cross-sectional position via the operation unit 24 (step SE12). As the change operation, a mouse operation on a display image, a mouse operation on a stenosis map, an input from a keyboard, or the like can be used. For example, the display section position is changed by performing a wheel operation of the operation unit 24 (mouse) on the display image. As another example, the display section position may be changed by sliding the section position mark on the stenosis map in the vertical direction via the operation unit 24.

  When the change operation is performed by the user via the operation unit 24 (step SE12: YES), the system control unit 28 causes the display cross-section position calculation unit 38 to perform display cross-section position calculation processing. In the calculation process, the display cross-section position calculation unit 38 calculates the changed display cross-section position based on the operation amount of the change operation received by the operation unit 24 (step SE13). More specifically, the display cross-section position calculation unit 38 calculates the change amount of the display cross-section position according to the operation amount, and calculates the calculated change amount and the cross-sectional position of the display image before change displayed in step SE12. By adding, the display cross-sectional position after the change is calculated. The calculated display cross-sectional position data is supplied to the display image generation unit 34 and the display control unit 20 by the system control unit 28.

  When the changed display cross-sectional position is calculated, the system control unit 28 causes the display image generation unit 34 to perform display image generation processing. In the generation process, the display image generation unit 34 reads the volume data set related to the calculated display cross-sectional position after the change from the processing data storage unit 10, and generates display image data from the read volume data set (step SE14). The display cross-sectional position of the generated display image is the same as the display cross-sectional position of the display image before the time phase change. The generated display image data is supplied from the system control unit 28 to the display control unit 20.

  When the display image data is generated, the system control unit 28 causes the display control unit 20 to perform display processing. In the display process, the display control unit 34 displays the stenosis map and the display image generated in step SE14 side by side (step SE15). At this time, the display image control unit 20 displays the changed display cross section calculated in step SE13. A cross-sectional position on the stenosis map corresponding to the position is specified, and the cross-sectional position mark is moved to the specified cross-sectional position. In this way, the display cross-sectional position and the cross-sectional position mark of the display image are updated in conjunction with the change of the display cross-sectional position via the operation unit 24.

  When the stenosis map and the display image are displayed in step SE15, the system control unit 28 ends the stenosis state analysis process.

  According to the above configuration, it is possible to change the display time phase of the display image via the operation unit 24 and to move the cross-sectional position mark on the stenosis map. In addition, the display cross-sectional position can be changed by moving the cross-sectional position mark on the stenosis map via the operation unit 24. In other words, the stenosis map can be made to function as a user interface for setting / changing the display cross-sectional position.

  Thus, the image processing apparatus 4 and the stenosis state analysis program according to the fourth modification of the present embodiment realize improvement in accuracy and efficiency of image diagnosis in a stenosis state.

  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, you may combine suitably the component over a different modification.

1 is a diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention. The figure which shows the typical flow of the stenosis state analysis process performed under control of the system control part of FIG. It is a figure which shows an example of the structure of the coronary artery area | region regarding step SA3 of FIG. The figure which shows an example of the coronary artery tree produced | generated in step SA3 of FIG. The figure for demonstrating the matching process concerning step SA3 of FIG. The figure which shows the graph of the stenosis rate calculated in step SA6 of FIG. The figure for demonstrating the specific process of the stenosis site | part in step SA7 of FIG. The figure which shows an example of the stenosis map produced | generated in step SA7 of FIG. The figure which shows the typical flow of the stenosis state analysis process concerning the modification 1 of this embodiment. The figure which shows the structure of the image processing apparatus concerning the modification 2 of this embodiment. The figure which shows the typical flow of a stenosis state analysis process performed under control of the system control part of FIG. The figure which shows an example of the display screen displayed in step SC11. The figure which shows the structure of the image processing apparatus concerning the modification 3 of this embodiment. The figure which shows the typical flow of a stenosis state analysis process performed under control of the system control part of FIG. The figure which shows the structure of the image processing apparatus concerning the modification 4 of this embodiment. The figure which shows the typical flow of a stenosis state analysis process performed under control of the system control part of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 10 ... Process data storage part, 12 ... Blood vessel extraction part, 14 ... Same blood vessel matching part, 16 ... Stenosis index value calculation part, 18 ... Stenosis state analysis part, 20 ... Display control part, 22 ... Display unit, 24 ... operation unit, 26 ... program storage unit, 28 ... system control unit

Claims (11)

A storage unit for storing a plurality of volume data sets relating to a plurality of time phases;
An extraction unit for extracting a blood vessel region from each of the plurality of volume data sets;
A calculation unit that calculates an index value indicating a degree of stenosis based on the shape of the blood vessel region for each of a plurality of cross sections substantially orthogonal to the core line of the extracted blood vessel region;
An analysis unit for analyzing the calculated index value in time series;
A display unit for displaying the analysis result of the time series analysis;
An image processing apparatus comprising :
The analysis unit
A time phase / position specifying unit for specifying a time phase and a cross-sectional position of a cross section indicating a clinically characteristic value of the calculated index value;
Based on the time phase and the cross-sectional position of the identified cross section, a map representing the time phase and the cross-sectional position where the stenosis is generated on a two-dimensional plane is generated, and the generated map is output as the analysis result A generating unit that
An image processing apparatus.   The image processing apparatus according to claim 1, wherein the calculation unit calculates at least one of a blood vessel diameter, a cross-sectional area, and a stenosis ratio of the blood vessel region on the cross section as the index value. A heart rate phase identifying unit that identifies a time phase of a specific heart rate phase from an electrocardiogram waveform;
The display unit is displayed over the prior Kemah Tsu on up the ECG mark indicating the phase when the identified,
The image processing apparatus according to claim 1 . A generator for generating cross-sectional image data relating to the cross-section having the characteristic value;
The display unit displays the cross-sectional image and the map side by side;
The image processing apparatus according to claim 1 . The image processing apparatus according to claim 4 , wherein the display unit displays a cross-sectional position mark indicating a cross-sectional position of the displayed cross-sectional image so as to overlap the map. The image processing apparatus according to claim 4 , wherein the display unit displays a cross-sectional time phase mark indicating a time phase of the displayed cross-sectional image so as to overlap the map. It further includes an operation unit that performs an operation of changing the cross-sectional position according to an instruction from the user
The display unit displays a cross-sectional image related to a cross-sectional position according to the operation amount of the change operation.
The image processing apparatus according to claim 4 . Wherein the display unit, the cross-sectional position mark indicating the cross-sectional position of the cross-sectional image that is the display and displayed superimposed on the map, moves the cross-sectional position mark on the map in accordance with the operation amount of the change operation The image processing apparatus according to claim 7 . An operation unit for performing an operation of changing the time phase of the displayed cross-sectional image according to an instruction from a user;
The display unit displays a cross-sectional image related to a time phase according to an operation amount of the change operation;
The image processing apparatus according to claim 4 . Wherein the display unit, the cross-sectional time phase mark indicating the time phase of the cross-sectional image being the display and displayed superimposed on the map, a phase mark at the section on the map according to the operation amount of the change operation The image processing apparatus according to claim 9 , which is moved. On the computer,
An extraction function to extract a blood vessel region from each of a plurality of volume data sets related to a plurality of time phases;
A calculation function for calculating an index value representing a blood vessel property based on the shape of the blood vessel region for each of a plurality of cross sections substantially orthogonal to the core line of the extracted blood vessel region;
An analysis function for time-series analysis of the calculated index value;
A display function for displaying the analysis result of the time series analysis;
A stenotic analysis program for realizing,
The analysis function is
A time phase / position specifying function for specifying a time phase and a cross-sectional position of a cross section indicating a clinically characteristic value of the calculated index value;
Based on the time phase and the cross-sectional position of the identified cross section, a map representing the time phase and the cross-sectional position where the stenosis is generated on a two-dimensional plane is generated, and the generated map is output as the analysis result A generation function to
A stenosis analysis program characterized by this.

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