JP5700712B2 - Patrac analysis of 3D dynamic myocardial nuclear medicine image data - Google Patents

Description

  The present invention relates to a Patrac analysis of three-dimensional dynamic myocardial nuclear medicine image data.

Background of the Invention

  Nuclear medicine imaging techniques, such as SPECT (Single Photon Emission Tomography) and PET (Positron Emission Tomography), administer drugs containing radionuclides into the body, This is a technique in which radiation emitted due to collapse is captured by a detector and imaged. To obtain a useful nuclear medicine image, a lot of radiation needs to be counted by the detector, so it would take a long time to collect the radiation, even if it was only to obtain a single tomographic image before. There was a need to do. Even so, with the advancement of detector performance, it was gradually possible to capture a large amount of radiation in a short time, but semiconductor detectors that have recently been put to practical use have dramatically increased the ability to detect radiation, Radiation counts sufficient for imaging can be obtained even if the data acquisition time is only a few seconds. For this reason, in recent years, radiation has been continuously detected immediately after administration of a radioactive tracer, and later, data is cut out and imaged every desired time, and the state of tracer uptake and metabolism is observed dynamically, that is, over time. Has come to be able to. PET or SPECT data collected continuously in time may be referred to as dynamic data.

  As a dynamic data observation method, for example, data may be cut out and imaged at predetermined time intervals such as every 5 seconds, and a desired cross-sectional image may be arranged in time to follow a time change of a bright imaged portion. However, such a method has a drawback that it is difficult to detect an overall decrease in the function of the tissue. For example, when examining the function of the myocardium, if the function of the myocardium decreases, the perfusion function of the blood to the myocardium is totally Therefore, it is difficult for the function deterioration to appear in the shade of the entire image, and to distinguish the abnormality.

  In addition, since an organ is a three-dimensional tissue, it is desirable that a temporal change can be observed based on a three-dimensional volume, rather than a two-dimensional temporal change such as a cross-sectional image. It is done.

  Each of the various configurations disclosed in the present specification has been developed for the purpose of solving at least one of the above-described problems.

  One of the novel configurations disclosed in this specification is the following method. The method includes extracting a myocardial region and a myocardial lumen region for each of a plurality of three-dimensional myocardial nuclear medicine image data having different data collection time zones;

  Obtaining a radioactivity count value associated with at least a portion of the extracted myocardial region for each of the plurality of three-dimensional myocardial nuclear medicine image data;

  Obtaining, for each of the plurality of three-dimensional myocardial nuclear medicine image data, a radioactivity count value associated with at least a portion of the extracted myocardial lumen region and corresponding to the portion of the myocardial region;

Calculate a constant representing the relationship between the calculated radioactivity count value of the myocardial region, the calculated radioactivity count value of the myocardial lumen region, and the time accumulated value of the calculated radioactivity count value of the myocardial lumen region. To do;
including.

  Here, the constant is substantially a ratio of the radioactivity count value of the myocardial region to the radioactivity count value of the myocardial lumen region, and a value relating to a time cumulative value of the radioactivity count value of the myocardial lumen region; Is a value corresponding to the slope when the relation is linearly approximated.

  According to the inventor's discovery, this slope can be considered to reflect the ability of the tracer to be taken into the myocardial tissue from blood in the blood vessel. It becomes gentle when resting, and becomes larger when a load is applied. In addition, those who have an abnormality in the function of the heart tend to have a gentler inclination than normal people. Therefore, by presenting information reflecting the above inclination to a person who performs nuclear medicine image diagnosis, it can be expected that the diagnostician will greatly assist in finding an abnormality.

  It should also be noted that the above slope or constant is a value that takes into account the three-dimensional structure of the myocardium. That is, the count value is calculated based on the three-dimensionally extracted myocardium and myocardial lumen, and the slope or constant is calculated. There are few known attempts to characterize the heart taking into account the three-dimensional structure of the myocardium, and the use of the slopes or constants described above is very original. In addition, since the heart is a three-dimensional organ, feature information based on a three-dimensional structure is more natural than feature information based on a two-dimensional analysis, and is more reliable and useful. I think that the.

  In addition, there is a description of “at least part of the extracted myocardial region” or “part of at least part of the extracted myocardial lumen region corresponding to the part of the myocardial region”. The reason described is that it may be “whole” in some embodiments. That is, depending on the embodiment, the count value and the cumulative value may be calculated from the entire myocardial region and the entire myocardial lumen. Therefore, the “part” referred to here is a concept including “whole”.

  The plurality of three-dimensional myocardial nuclear medicine image data may correspond to different time positions of three-dimensional dynamic myocardial nuclear medicine image data, for example, three-dimensional dynamic myocardial SPECT image data.

In a preferred embodiment, the value related to the time accumulated value of the radioactivity count value of the myocardial lumen region can be as follows.
[Formula 1]
Here, fi (t) is the radioactivity count value of the myocardial lumen region in the time zone represented by time t.

Therefore, when the above constant is expressed as k, the above linear approximation can be expressed as follows.
[Formula 2]
here,
It is.

However,
It is not necessary to approximate the fitting of Equation 2 in a straight line in all ranges. Rather, the range in which linear approximation seems appropriate is
Is only a small area. Therefore, it is preferable that the range in which the above linear approximation is performed can be arbitrarily set by the user. It is also preferable that the range for performing the above linear approximation is automatically set. For example,
When
The linear approximation may be performed only in a range in which the correlation coefficient between and is not less than a predetermined value (for example, a range not less than 0.7).

  The above-described method can be implemented as a method performed by the apparatus by executing a computer program by the processing means of the apparatus, for example. Further, for example, the present invention can be implemented as a computer program that causes the apparatus to execute the above-described method by being executed by the processing means of the apparatus. Also, for example, it can be implemented as an apparatus configured to perform the method described above.

  Examples of specific embodiments will be introduced below with reference to the following drawings.

1 is a diagram for describing a main configuration of an apparatus or system 100 for executing various processes disclosed in the present specification. 5 is a flowchart for explaining a part of processing by a Patrac analysis program 160. It is a figure for demonstrating the example of the result of a myocardial outline extraction process. It is a figure for demonstrating the method of segment division. It is an example which graphed the time change of the count number. FIG. 6 is a diagram for explaining a part of processing by a Patrac analysis program 160. FIG. 6 is a diagram for explaining a part of processing by a Patrac analysis program 160.

DESCRIPTION OF PREFERRED EMBODIMENTS

  FIG. 1 is a diagram for explaining a main configuration of a system 100 for executing various processes disclosed in this specification. As illustrated in FIG. 1, the system 100 is similar to a general computer in hardware, and includes a CPU 102, a main storage device 104, an auxiliary storage device 106, a display interface 107, a peripheral device interface 108, a network interface. An interface 109 or the like can be provided. Similar to a general computer, a high-speed RAM (Random Access Memory) can be used as the main storage device 104, and an inexpensive and large-capacity hard disk or SSD can be used as the auxiliary storage device 106. . A display for displaying information can be connected to the system 100, which is connected via a display interface 107. In addition, a user interface such as a keyboard, a mouse, and a touch panel can be connected to the system 100, and this is connected via a peripheral device interface 108. The network interface 109 can be used to connect to another computer or the Internet via a network. The most basic function of the system 100 is provided by the CPU 102 reading and executing the operating system 110 stored in the auxiliary storage device 106. In addition, various programs (for example, program 160) stored in the auxiliary storage device 106 are read and executed by the CPU 102, so that functions other than the functions provided by the operating system 110, for example, see FIG. The functions described below are provided.

The auxiliary storage device 106 may store raw data 149 obtained by SPECT or PET dynamic scan performed on the myocardium. When collecting data for the myocardium using SPECT, ²⁰¹ TlCl (thallium chloride) or ^99m Tc-tetrofosmin (tetrofosmin) is a radioactive material that is incorporated into cardiomyocytes in proportion to coronary blood flow. Often the substance is administered to the subject as a tracer. The raw data 149 can be, for example, data in which the count number of gamma rays is stored for several tens of minutes to several hours immediately after administration of the tracer, for each detection unit (for example, for each cell of the semiconductor detector), unit time. It can be data having a gamma ray count number as a data value every time (for example, every time resolution of the apparatus).

  The auxiliary storage device 106 may also store data 150 to be subjected to the Patrac analysis described in detail with reference to FIG. The data 150 is data that includes the count number information of the raw data 149 that has been cut out and imaged at predetermined time intervals, that is, data that includes a time series of three-dimensional nuclear medicine image data. Information about time is given to each three-dimensional nuclear medicine image data, for example, even if information showing how many seconds later the image is represented when the administration start time of the radioactive tracer is set to 0 seconds is given. Good. Each three-dimensional nuclear medicine image data is composed of a set of two-dimensional nuclear medicine image data that images different sections of the organ to be measured, and as a whole, from the two-dimensional image set that provides three-dimensional information of the whole organ. Composed. The data 150 may include one set of three-dimensional nuclear medicine image data every predetermined time (for example, every 5 seconds). When the organ to be imaged is a ventricle (myocardium), each three-dimensional nuclear medicine image data may be referred to as three-dimensional myocardial nuclear medicine image data.

  Data composed of a time series of three-dimensional nuclear medicine image data, such as data 150, may be referred to as dynamic nuclear medicine data. For example, dynamic nuclear medicine data obtained using SPECT may be referred to as dynamic SPECT data. In addition, dynamic nuclear medicine data obtained by a dynascan for the myocardium (ventricle) may be referred to as dynamic myocardial nuclear medicine data.

  The analysis result example introduced in the later drawings is an analysis of dynamic myocardial SPECT data obtained by performing SPECT measurement for the left ventricle. The same applies to dynamic data obtained by PET. Analysis can be performed. The auxiliary storage device 106 may store a Patrac analysis program 160, which is a central element for executing the Patrac analysis described in detail with reference to FIG. The Patrac analysis program 160 is a program for extracting 3D myocardial nuclear medicine image data at each time point from the data 150, and calculating and analyzing feature quantities for each 3D image data. As an example, the Patrac analysis program 160 may be programmed to consist of modules 162-168 as shown. The image extraction module 162 is a module that extracts three-dimensional nuclear medicine image data at a specific time from the dynamic nuclear medicine data 150. The module 162 may be configured to store the extracted three-dimensional image data in the auxiliary storage device 106, as exemplified by the data 151, 152, and the like. The slice operation module 164 is a program for creating a two-dimensional slice by cutting out the three-dimensional image extracted by the module 162 with a free cross section. Since there are many programs for cutting out a two-dimensional slice from a three-dimensional image, the module 164 can be created using the source code of such a program.

  The myocardial contour extraction module 166 is a program for automatically extracting the contour of the myocardium from the three-dimensional image data extracted by the module 162. Although the existing myocardial contour automatic extraction algorithm placed on the module 166 can use an existing algorithm, the algorithm disclosed in the international patent application (PCT / JP2012 / 74516) by the applicant is particularly suitable. The contents of PCT / JP2012 / 74516 form part of this specification. The Patrac analysis module 168 is a module for performing the Patrac analysis described with reference to FIG. Details of the Patrac analysis performed by the module 168 will be described later with reference to FIG.

  It should be noted that such a module configuration of the Patrac analysis program 160 is merely an example, and there may be various embodiments of the program 160. Embodiments that do not have a module configuration are possible, and there are cases in which two or more of the modules 162 to 168 are combined, or any module is separated into two or more modules. is there. Alternatively, the Patrac analysis program 160 itself may be clearly provided as a set of a plurality of programs. Those of ordinary skill in the art will be able to use the various programming programs and programming environments based on the disclosure of the present specification and equivalent to the Patrac analysis program 160 and / or the modules 162-168. It would be possible to create a program that has the following functions.

  In some embodiments, the auxiliary storage device 106 may store a program 170 for creating the dynamic nuclear medicine data 150 from the raw data 149. When the program 170 is executed by the CPU 102, the count data of the raw data 149 is cut out every predetermined time (for example, every 5 seconds), and the count data is converted into image data by using a two-dimensional inverse Fourier transform for each slice. A set of three-dimensional nuclear medicine image data is constructed. Reconstruction of count data into an image is a well-known process.

  In addition to the elements depicted in FIG. 1, the system 100 can have a configuration similar to that of an apparatus included in a normal computer system, such as a power supply or a cooling device. Various types of computer system implementations are known, such as those using storage device distribution / redundancy and CPU virtualization, but what is disclosed in this specification? It may be mounted on a computer system of any form. The items disclosed in this specification are generally (1) executed by a processing unit to cause an apparatus or a system including the processing unit to perform various processes described in this specification. (2) an operation method of an apparatus or a system realized by executing the program by the processing means, and (3) a process configured to execute the program and the program. The present invention can be embodied as an apparatus or a system including means.

  Although only one dynamic data 150 is depicted in FIG. 1, of course, more dynamic data may be stored in the auxiliary storage device 106, eg, collected under load conditions for the same subject. Data and data collected under resting conditions, data collected at different times, data collected for different subjects, and the like may be stored. The Patrac analysis program 160 may be configured to perform the analysis described herein on each of these dynamic data and compare the results between the data.

  Next, details of processing executed by executing the Patrac analysis program 160 by the CPU 102 will be described with reference to the flowchart of FIG. The process described in this flowchart is a process performed by a program instruction included in the modules 164 to 168 in the Patrac analysis program 160 in particular.

  Step 200 represents the start of processing. In step 202, the dynamic data 150 described above is loaded, and at least a part of the dynamic data 150 is stored in the main storage device 104. In the loop of steps 204 to 218, 3D myocardial SPECT image data corresponding to a specific time is extracted from the dynamic myocardial SPECT data 150, and predetermined processing is performed on each 3D myocardial SPECT image data. Step 206 represents the extraction process. A set of three-dimensional SPECT image data corresponding to a specific time point is extracted from the data 150 and temporarily stored in the RAM 104, for example.

  In step 210, processing for extracting the outline of the myocardial epicardium and the outline of the myocardium intima from the three-dimensional SPECT image represented by the data extracted in step 206 is performed. Although it is not easy to extract myocardial contours from SPECT images, there are several techniques that can be used. Among them, in particular, the myocardial contour extraction method disclosed in the international patent application (PCT / JP2012 / 74516) by the applicant can extract the myocardial contour very well as compared with other methods. Also at 210, it is preferable to perform myocardial contour extraction using the method described in this international patent application. Step 210 may be a process performed when the CPU 102 executes a program command of the myocardial contour extraction module 166. The myocardial contour extraction module 166 may be configured to call and use the slice operation module 164 during the processing. It should be noted that the myocardial contour extraction algorithm implemented by the Patrac analysis program 160 or the myocardial contour extraction module 166 is not limited to the one disclosed in the above international patent application (PCT / JP2012 / 74516). It is described for the purpose.

  An example of the result of the myocardial contour extraction process will be introduced with reference to FIG. FIG. 3 shows various sectional views of axial, coronal, and sagittal extracted from the three-dimensional SPECT image data extracted in step 206 using the program command of the slice operation module 164. The myocardial contour extracted using the program command of the myocardial contour extraction module 166 is displayed as a white line. The area inside the outline of the myocardium can be considered as the myocardial lumen region.

  Step 212 represents a process of dividing the myocardium and myocardial lumen identified as a result of step 210 into segments. Any segment may be used, but for example, the myocardium may be divided so as to correspond to a well-known polar map segment. The myocardial lumen may be divided so as to correspond to the divided myocardial part.

  FIG. 4 is a diagram for explaining a segment division technique. FIG. 4A depicts an example of a polar map. In this example, a polar map 400 having three segments 402, 404, and 406 is depicted. On the other hand, what is depicted in FIG. 4B is a schematic representation of a short-axis cross-sectional image of a short-axis cross-sectional slice cut out from the three-dimensional SPECT image extracted in step 206. In this cross-sectional image 420, reference numeral 422 represents the center of the ventricle, and reference numeral 424 represents the myocardial surface extracted in step 210. By developing the myocardial intimal surface in the polar map 400, it has been found that the arc extending from the points 426 to 428 in the myocardial intimal surface 424 corresponds to, for example, the segment 402 in the polar map 400 of FIG. 4A. To do. Further, it is assumed that the arc extending from the points 428 to 430 corresponds to the segment 406, for example, and the arc extending from the points 430 to 426 corresponds to the segment 404, for example. At this time, the pixels included in the arc 426-428 are defined as the myocardial segment pixels corresponding to the segment 402, and the pixels included in the substantially fan-shaped region defined by the center 422 and the arc 426-428 are defined as the myocardial lumen. The pixel of the segment 402 is defined. Similarly, pixels included in the arc 430-426 are defined as pixels of the myocardial segment corresponding to the segment 404, and pixels included in the substantially fan-shaped region defined by the center 422 and the arc 430-426 are defined as the myocardial lumen. The pixel of the segment 404 is defined. The pixels included in the arcs 428-430 are defined as the myocardial segment pixels corresponding to the segment 406, and the pixels included in the substantially fan-shaped region defined by the center 422 and the arcs 428-430 are defined as the myocardial lumen segment. It is defined as 406 pixels. By executing this process for all short-axis cross-sectional slices, the pixels belonging to each myocardial segment and each myocardial lumen segment can be identified.

In step 214, for each segment of the myocardium / myocardial lumen divided in step 212, the total count number in the segment is calculated. Further, in step 216, for each segment of the myocardial lumen, a value as represented by Equation 3 or Equation 3 ′ is calculated.
[Formula 3]
[Formula 3 ']
Here, fi (t) is the total count number of a specific myocardial lumen segment in a time zone represented by time t. For example, when the time width cut out in step 206 is 5 seconds, and t = 300, fi (t) is the myocardial lumen segment between 296 and 300 seconds from the administration time of the radiation tracer. Represents the total count of. Actually, the integral cannot be calculated analytically as in Expression 3, so the calculation is performed in the form of Expression 3 ′. fi (n) represents the total count of the myocardial lumen segment when the loop variable of step 204 is n. Equation 3 ′ is one embodiment of Equation 3, and Equation 3 ′ is included in the embodiment of Equation 3.

  As can be understood from Equation 3 or Equation 3 ′, the value calculated in Step 216 is a value related to the time cumulative value of the total count of the myocardial lumen segment, and the time cumulative value is The value is divided by the total count of the myocardial lumen segment in the newest time zone.

  For all the three-dimensional image data included in the data 150, when the processing of Steps 210 to 218 is completed, the loop is exited and the processing result is stored (Step 220). The processing result data is a total count for each of the myocardial segments divided in step 212 for each time interval (eg, 1-5 seconds, 6-10 seconds,... 396-400 seconds,...). For each of the myocardial lumen segments, the data has a total count and a value related to the time cumulative value. In step 220, the processing result data may be stored in the auxiliary storage device 106 as, for example, analysis data 156. Although only one analysis data 156 is depicted in FIG. 1, for example, when there are a plurality of dynamic data 150 to be processed and the above processing is performed on each of the dynamic data 150, the analysis data 156 is displayed for each. It is created and stored in the auxiliary storage device 106. Depending on the embodiment, steps 212 to 216 and 220 may be processing performed by executing a program instruction of the Patrac analysis module 168 to the CPU 102.

  Next, an example of displaying or further analyzing the data of the above processing result will be introduced.

  FIG. 5 is an example in which the change in the count number with time is graphed. This display may be a display obtained by executing the program instruction of the parc track analysis module 168 to the CPU 102. The upper graph is a graph of a part of the data obtained by performing the above processing on dynamic data collected under load conditions, and the lower graph is collected under rest conditions. A part of the data obtained by performing the above processing on the dynamic data is graphed. The horizontal axis represents time, and the vertical axis represents the average SPECT count (the value obtained by dividing the total SPECT count by the total number of pixels in the target area). The origin of the time axis can be, for example, the time when the radioactive tracer is administered. The broken lines 502 and 502 ′ represented by dotted lines are connected by plotting the data of the average SPECT count number of the myocardial lumen region, and the broken lines 504 and 504 ′ represented by solid lines are the myocardial region. The average SPECT count data is plotted and connected. In FIG. 5, both the broken lines 502 and 502 ′ represent the average count number of the entire myocardial lumen region, and the broken lines 504 and 504 ′ both represent the average count number of the entire myocardial region. However, depending on the embodiment, the Patrac analysis module 168 may display a similar graph with the count number of only the area when the desired area of the polar map 506 displayed on the right side is selected with a mouse or the like. It is preferably configured to display. Depending on the embodiment, the value on the vertical axis may be normalized and displayed with an appropriate value.

  As shown in the figure, the polygonal lines 502 and 502 ′ have a profile that rises rapidly from about 30 seconds and then decreases rapidly, which means that the administered radioactive tracer reaches the left ventricular lumen. (The data analyzed in the above example was measured for the left ventricle as described above), and it shows how it is carried throughout the body as the ventricle contracts. On the other hand, the broken line 504 gradually rises and becomes flat after about 120 seconds, which indicates that the radioactive tracer is taken into the myocardial cells after about 120 seconds from the administration.

  However, as can be seen by comparing the two graphs in FIG. 5, there is not much difference in the shape of the broken line between the upper graph that is a graph under a load condition and the lower graph that is a graph under a rest condition. Therefore, in order to clearly grasp such a difference in change, an analysis based on a plot as described below with reference to FIG. 6 is useful.

FIG. 6 is a diagram for explaining a unique analysis method by the Patrac analysis program 160. FIG. 6 shows four graphs. The upper two (graphs 600 and 620) are graphs of analysis data 156 obtained by processing dynamic data under load conditions. These two (graphs 610 and 630) are graphs of analysis data 156 obtained by processing dynamic data under resting conditions. The graphs 620 and 630 on the left are graphs of the change over time in the counts of all myocardial regions and all myocardial lumen regions, and are the same as the two graphs depicted in FIG. On the other hand, the graphs 600 and 610 on the right are obtained by plotting points (x (t), y (t)) calculated as in Expression 4.
[Formula 4]
In Equation 4, fo (t) and fi (t) represent the total counts of a specific myocardial segment and the corresponding myocardial lumen segment in the time zone represented by time t, respectively. For example, when the time width cut out in step 206 is 5 seconds and t = 300, fo (t) and fi (t) are 296 to 300 seconds from the administration time of the radiation tracer, respectively. The total count number of the myocardial segment and the myocardial lumen segment in between. However, fo (t) and fi (t) in the example of FIG. 6 represent the total counts of all myocardial segments (that is, the entire myocardial region) and all myocardial lumen segments (that is, the entire myocardial lumen region). ing. That is, the entire myocardial region and the entire myocardial lumen region are considered as a myocardial segment and a myocardial lumen segment, respectively. In Equation 4, x (t) is a value calculated in step 216 of FIG. 2, and is a value related to the time accumulated value of the total count number of the myocardial lumen segment. y (t) is the ratio of the radioactivity count value of the myocardial region to the radioactivity count value of the myocardial lumen region in the time zone represented by time t. FIG. 6 is a graph in which (x (t), y (t)) is calculated and t varied in various ways. FIG. 6 shows some of these points by giving reference numerals 602 and 612 to some of the above points (x (t), y (t)). The values on the horizontal axis of graphs 600 and 610 are
And the value on the vertical axis is
It is.

In the graph 600, a straight line 606 is a linear approximation of a set of points 602 within a specific range (within a range between two straight lines 604). The approximate expression can be expressed as:
[Formula 5]

  In Equation 5, fo (t) and fi (t) represent the total counts of a specific myocardial segment and the corresponding myocardial lumen segment in the time zone represented by time t as described above. The constant k represents the slope of the straight line, and the constant D represents the intercept of the straight line.

  A straight line 616 in the graph 610 is also a line approximation of a set of 612 within a range between two straight lines 614.

  As described above, the graph 600 is a graph obtained by processing dynamic data collected under a load condition, and the graph 610 is a graph obtained by processing dynamic data collected under a rest condition. . Comparing these graphs, it can be seen that the slope of the straight line 606 in the graph 600 under the load condition is clearly larger than the slope of the straight line 616 in the graph 610 under the resting condition. Therefore, it can be understood that this slope, that is, the constant k in Equation 5, is useful information for comparing dynamic data obtained under different conditions.

  The constant k in Equation 5 is a value calculated based on the myocardium extracted three-dimensionally or the myocardial lumen extracted three-dimensionally. That is, it is a value calculated based on the gamma ray count number in the myocardium extracted three-dimensionally and the gamma ray count number in the myocardial lumen extracted three-dimensionally. Since the heart is a three-dimensional organ, feature information based on a three-dimensional structure is more natural than feature information based on a two-dimensional analysis, and is considered to be more reliable and useful.

  As described above, the range in which the set of points 602 and 612 is linearly approximated in the graphs 600 and 610 is only a part of the whole. In some embodiments, this range may be configured to be determined manually. The Patrac analysis module 168 is preferably configured to allow the user to determine a range for linear approximation, for example, by moving the straight lines 604 and 614 with a mouse or the like. In some embodiments, this range may be configured to be determined automatically. For example, scanning from a small area of x (t), and linearly approximating only the range where the correlation coefficient of (x (t), y (t)) is more than a certain value (eg 0.7 or more) Also good. Further, depending on the embodiment, a range of t (that is, a time domain) in which the points (x (t), y (t)) are plotted may be limited. For example, in the example of FIG. 6, in the graphs 620 and 630, x (t) and y (t) are calculated and plotted in the graphs 600 and 610 only for the time region on the right side of the straight lines 622 and 632. As can be understood from the graphs 620 and 630, the straight lines 622 and 632 indicate the time when the myocardial lumen count starts to increase, that is, the time when the myocardial lumen is considered to have reached after administration of the radioactive tracer. In some embodiments, the Patrac analysis module 168 is preferably configured to allow the user to set the range for calculating and plotting the points 602, 612, for example, by moving the straight line 622 or 632 with a mouse or the like. . Depending on the embodiment, it may be configured to automatically set a time region for calculating and plotting the points 602 and 612 using an appropriate threshold value or the like. For example, the points 602 and 612 may be calculated and plotted after a time when, for example, 10% of the peak value of the count value of the myocardial lumen is first exceeded.

  FIG. 7 shows the above-described constant k calculated for the myocardial region and myocardial lumen region corresponding to each segment of the myocardial polar map and displayed on the polar map. The map 702 displays a constant k calculated for each segment based on the myocardial SPECT dynamic data collected under the load condition, superimposed on the segment. On the other hand, the map 704 displays a constant k calculated for each segment on the basis of the myocardial SPECT dynamic data collected under resting conditions. The map 706 displays the value ks / kr on the corresponding segment when the constant k under load condition is expressed as ks and the constant k under rest condition is expressed as kr. By providing such a map, it is easy to determine in which part of the ventricle (the left ventricle in this example) the constant k is large, that is, whether the slope of the straight line 606 or 616 in the graph 600 or 610 in FIG. 6 is large. Can be determined.

  Further, as shown in the figure, the maps 702 to 706 represent the segment having the largest value in white, the segment having the smallest value in black, and the segment having the intermediate value in gray. In this way, by changing the display color depending on the magnitude of the value, the difference of each part of the constant k can be easily determined. It is also interesting that the segment with the higher value in the ratio map 706 is different from the segment with the higher value in the maps 702 and 704.

  While embodiments of the present invention have been described using preferred examples, these examples have not been introduced to limit the scope of the present invention, but to meet the requirements of the patent law and contribute to an understanding of the present invention. It was introduced in. The present invention can be embodied in various forms, and there are many variations in the embodiments of the present invention other than those exemplified here. The individual features included in the various described embodiments can only be used with the embodiments in which the features are directly described, and are not limited to the other embodiments and descriptions described herein. It can also be used in combination in various implementations that are not. In particular, the order of the processes introduced in the flowchart does not necessarily have to be executed in the order in which they are introduced. Depending on the preference of what is to be implemented, the order may be changed or executed in parallel or as an appropriate loop. It may be implemented to execute. For example, depending on the embodiment, the data to be loaded in step 202 is the raw data 149, and in step 206, the count data for a predetermined time (for example, 5 seconds) is cut out from the raw data 149 and imaged to obtain a three-dimensional image. It may be a step of providing data. All of these variations are included in the scope of the present invention. The description order of the processes specified in the claims does not necessarily specify the essential order of the processes. For example, an embodiment in which the order of the processes is different, an embodiment in which the processes are executed including a loop, etc. Is also included in the scope of the claimed invention. Regardless of whether a claim is made in the current claims, the applicant claims to have the right to obtain a patent for all forms that do not depart from the spirit of the present invention. Keep in mind.

100 System 104 Main Memory 106 Auxiliary Memory 107 Display Interface 108 Peripheral Device Interface 109 Network Interface 110 Operating System 150 Dynamic Data 156 Analysis Data 160 Partrack Analysis Program 162 Image Extraction Module 164 Slice Operation Module 166 Myocardial Contour Extraction Module 168 Patrac analysis module

Claims (11)

A method performed by the apparatus by a computer program being executed by the processing means of the apparatus,
Extracting a myocardial region and a myocardial lumen region for each of a plurality of three-dimensional myocardial nuclear medicine image data having different data collection time zones;
Obtaining a radioactivity count value of a portion of the extracted myocardial region for each of the plurality of three-dimensional myocardial nuclear medicine image data;
For each of the plurality of three-dimensional myocardial nuclear medicine image data, it said extracted a part of intramyocardial lumen region, and the portion of the myocardial region, a plurality of short axis crossing of the three-dimensional myocardial nuclear medicine image data in each cross-sectional slices and determining the radioactivity count value of the portion defined by the ventricular heart;
Calculate a constant representing the relationship between the calculated radioactivity count value of the myocardial region, the calculated radioactivity count value of the myocardial lumen region, and the time accumulated value of the calculated radioactivity count value of the myocardial lumen region. To do;
Including ,
The constant is a linear approximation of the relationship between the ratio of the radioactivity count value of the myocardial region to the radioactivity count value of the myocardial lumen region and the value related to the time accumulated value of the radioactivity count value of the myocardial lumen region. Ri value der which corresponds to the slope of the time,
The value for the time cumulative value is
It can be expressed as, where fi (t) is Ru radioactivity count der intramyocardial cavity region in the time zone represented by the time t,
Method. The method according to claim 1 , wherein each of the plurality of three-dimensional myocardial nuclear medicine image data corresponds to a different time position of the dynamic myocardial nuclear medicine data. The method according to claim 1 or 2 , wherein the plurality of three-dimensional myocardial nuclear medicine image data is image data obtained by SPECT. Range for the linear approximation, said ratio, the correlation coefficient between the value relating to the time accumulated value is within a range of equal to or greater than a predetermined value, the method according to any one of claims 1 to 3. Based on user input comprises setting a range for the linear approximation method as claimed in any one of claims 1 to 3. For each segment of the myocardium polar map, further comprising the method according to any one of claims 1 to 5 to provide a map showing the information on the constants. For each segment of the myocardial polar map, information on the ratio between the constant calculated from the myocardial nuclear medicine image obtained under the load condition and the constant calculated from the myocardial nuclear medicine image obtained under the resting condition was expressed. further comprising a method according to any one of claims 1 to 6 to provide a map. By being executed by the processing means of the apparatus comprises program instructions for executing the method according to any one of claims 1 to 7 to the device, the computer program. An apparatus comprising a processing means and memory means, said memory means stores program instructions for executing the method according to any one of claims 1 to 7 in the apparatus by being executed by said processing means ,apparatus. Means for extracting a myocardial region and a myocardial lumen region for each of a plurality of three-dimensional myocardial nuclear medicine image data having different data collection time zones;
Means for obtaining a radioactivity count value of a portion of the extracted myocardial region for each of the plurality of three-dimensional myocardial nuclear medicine image data;
For each of the plurality of three-dimensional myocardial nuclear medicine image data, it said extracted a part of intramyocardial lumen region, and the portion of the myocardial region, a plurality of short axis crossing of the three-dimensional myocardial nuclear medicine image data Means for determining a radioactivity count value of the portion defined by the center of the ventricle in each of the cross-sectional slices ;
Calculate a constant representing the relationship between the calculated radioactivity count value of the myocardial region, the calculated radioactivity count value of the myocardial lumen region, and the time accumulated value of the calculated radioactivity count value of the myocardial lumen region. Means to do;
With
The constant is a linear approximation of the relationship between the ratio of the radioactivity count value of the myocardial region to the radioactivity count value of the myocardial lumen region and the value related to the time accumulated value of the radioactivity count value of the myocardial lumen region. Ri value der which corresponds to the slope of the time,
The value for the time cumulative value is
It can be expressed as, where fi (t) is Ru radioactivity count der intramyocardial lumen region in the time zone represented by the time t,
apparatus. The apparatus of claim 10, further comprising means for providing a map representing information about the constant for each segment of a myocardial polar map.