Method, apparatus, and program for determining cause and / or treatment policy of acute phase cerebral infarction

Abstract

The present invention provides a method, a device, and a program for effectively determining the cause and / or treatment policy of acute phase cerebral infarction. The method for determining the cause and / or treatment policy of acute phase cerebral infarction uses, as an indicator, an acute chronic mismatch value representing the difference or ratio between a representative value representing the maximum concentration arrival time of a contrast agent and a representative value representing the average transit time of the contrast agent, both of the representative values being obtained from cerebral perfusion image data of a patient who has developed acute phase cerebral infarction.

Description

Method, device and program for determining the cause and / or treatment plan for acute cerebral infarction

[0001] The present invention relates to a method, an apparatus, and a program for determining the cause and / or treatment plan for acute cerebral infarction.

[0002] Non-Patent Document 1 describes that Tmax obtained from MR (magnetic resonance) perfusion images is more correlated with cerebral blood flow (CBF) obtained by xenon CT (computed tomography) than is mean transit time (MTT).

[0003] Olivot JM et. al., "Perfusion MRI (Tmax and MTT) correlation with xenon CT cerebral blood flow in stroke patients", Neurology. 2009, Mar 31; 72(13): 1140-1145

[0004] However, it has traditionally been difficult to properly determine the cause of a patient's acute cerebral infarction and the course of treatment based on cerebral perfusion parameters obtained from the patient's cerebral perfusion images.

[0005] The present invention has been made in consideration of the above-mentioned problems, and one of its objects is to provide a method, device, and program for effectively determining the cause and / or treatment policy of acute cerebral infarction.

[0006] [1] A method according to one embodiment of the present invention for solving the above problems is a method for determining the cause and / or treatment plan of acute cerebral infarction, which uses an acute-chronic mismatch value, obtained from cerebral perfusion image data of a patient who has developed acute cerebral infarction, as an index, which represents the difference or ratio between a representative value representing the time to reach maximum concentration of a contrast agent and a representative value representing the mean transit time of the contrast agent. According to the present invention, a method for effectively determining the cause and / or treatment plan of acute cerebral infarction is provided.

[0007] [2] In the method of [1], the acute-chronic mismatch value may be compared with a predetermined judgment criterion, and the cause and / or treatment policy of the acute cerebral infarction may be determined based on the result of the comparison. [3] In the method of [2], the comparison may be based on the result of the comparison to determine: (a) the possibility that the cause of the acute cerebral infarction in the patient is related to chronic stenosis; and / or (b) the need to consider the presence of a chronic stenotic site in the treatment of the acute cerebral infarction in the patient. [4] In the method of [3], if the acute-chronic mismatch value satisfies the judgment criterion, it may be determined that: (a) one of the causes of the acute cerebral infarction in the patient was likely acute occlusion of a chronic stenotic site in the patient's major cerebral artery; and / or (b) in the treatment of the acute cerebral infarction in the patient, it is highly necessary to prepare a treatment that assumes the presence of a chronic stenotic site in the patient's major cerebral artery.

[0008] [5] An apparatus according to one embodiment of the present invention for solving the above problems is an apparatus for determining the cause and / or treatment plan of acute cerebral infarction, and includes a calculation processing unit that calculates an acute-chronic mismatch value representing the difference or ratio between a representative value representing the maximum concentration arrival time of a contrast agent and a representative value representing the mean transit time of a contrast agent, from cerebral perfusion image data of a patient who has developed acute cerebral infarction. According to the present invention, an apparatus for effectively determining the cause and / or treatment plan of acute cerebral infarction is provided.

[0009] [6] The device of [5] may further include a comparison processing unit that compares the acute-chronic mismatch value with a predetermined judgment criterion and generates comparison result data representing the result of the comparison. [7] In the device of [6], the comparison processing unit may generate the comparison result data based on the result of the comparison, including: (a) judgment result data representing a possibility that the cause of the acute-phase cerebral infarction of the patient is related to chronic stenosis; and / or (b) judgment result data representing the need to consider the presence of a chronic stenosis site in treating the acute-phase cerebral infarction of the patient. [8] In the device of [7], when the acute-chronic mismatch value satisfies the judgment criterion, the comparison processing unit may generate the comparison result data including: (a) judgment result data indicating that one of the causes of the acute cerebral infarction of the patient was likely to be acute occlusion of a chronic stenosis site in the patient's major cerebral artery; and / or (b) judgment result data indicating that, in treating the acute cerebral infarction of the patient, it is highly necessary to prepare treatment that assumes the presence of a chronic stenosis site in the patient's major cerebral artery.

[0010] [9] A program according to one embodiment of the present invention for solving the above problem is a program for determining the cause and / or treatment plan of acute cerebral infarction, which causes a computer to execute a calculation processing step of calculating an acute-chronic mismatch value representing the difference or ratio between a representative value representing the maximum concentration arrival time of a contrast agent and a representative value representing the mean transit time of a contrast agent, from cerebral perfusion image data of a patient who has developed acute cerebral infarction. According to the present invention, a program for effectively determining the cause and / or treatment plan of acute cerebral infarction is provided.

[0011]

[10] The program of [9] may further cause the computer to execute a comparison processing step of comparing the acute-chronic mismatch value with a predetermined judgment criterion and generating comparison result data representing the result of the comparison.

[11] The program of

[10] may cause the computer to execute the comparison processing step of generating, based on the result of the comparison, the comparison result data including: (a) judgment result data representing a possibility that the cause of the acute-phase cerebral infarction of the patient is related to chronic stenosis; and / or (b) judgment result data representing the need to consider the presence of a chronic stenosis site in treating the acute-phase cerebral infarction of the patient.

[12] The program of

[11] may be configured to cause the computer to execute the comparison processing step of generating the comparison result data including, when the acute-chronic mismatch value satisfies the judgment criterion: (a) the judgment result data indicating that one of the causes of the acute cerebral infarction of the patient was likely to be acute occlusion of a chronic stenosis site in the patient's major cerebral artery; and / or (b) the judgment result data indicating that, in treating the acute cerebral infarction of the patient, it is highly necessary to prepare treatment that assumes the presence of a chronic stenosis site in the patient's major cerebral artery.

[0012] According to the present invention, a method, device and program for effectively determining the cause and / or treatment policy of acute cerebral infarction are provided.

[0013] FIG. 1 is an explanatory diagram showing an example of the main hardware configuration of an apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of main functions realized by an apparatus according to an embodiment of the present invention. FIG. 3 is a flow diagram showing an example of steps performed in a method according to an embodiment of the present invention and / or executed by a computer by a program according to an embodiment of the present invention. FIG. 4 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 1 of an example according to an embodiment of the present invention. FIG. 5 is an explanatory diagram showing another example of a cerebral perfusion image used in representative case 1 of an example according to an embodiment of the present invention. FIG. 6 is an explanatory diagram showing yet another example of a cerebral perfusion image used in representative case 1 of an example according to an embodiment of the present invention. FIG. 7 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration time and the mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether a chronic stenosis site was found in a major cerebral artery, in representative case 1 of an example according to an embodiment of the present invention. FIG. 8 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 1 of an example according to an embodiment of the present invention. FIG. 9 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 2 of an example according to an embodiment of the present invention. FIG. 1 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration arrival time and mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery in representative case 2 of an example according to one embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 3 of an example according to one embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 3 of an example according to one embodiment of the present invention. FIG. 4 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration arrival time and mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery in representative case 3 of an example according to one embodiment of the present invention. FIG. 5 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 3 of an example according to one embodiment of the present invention. FIG. 6 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 4 of an example according to one embodiment of the present invention.FIG. 1 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration time and mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery in representative case 4 of an example according to one embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 4 of an example according to one embodiment of the present invention. FIG. 3 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 5 of an example according to one embodiment of the present invention. FIG. 4 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration time and mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery in representative case 5 of an example according to one embodiment of the present invention. FIG. 5 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 5 of an example according to one embodiment of the present invention. FIG. 6 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 6 of an example according to one embodiment of the present invention. FIG. 7 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration time and mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery in representative case 6 of an example according to one embodiment of the present invention. FIG. 1 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 6 of an example according to one embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 7 of an example according to one embodiment of the present invention. FIG. 3 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration arrival time and the mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery, in representative case 7 of an example according to one embodiment of the present invention. FIG. 4 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 7 of an example according to one embodiment of the present invention. FIG. 5 is an explanatory diagram showing an example of a cerebral perfusion image used in representative case 8 of an example according to one embodiment of the present invention. FIG. 6 is an explanatory diagram showing the results of calculating representative values ​​of the maximum concentration arrival time and the mean transit time, and the acute-chronic mismatch value, and the evaluation result of whether or not a chronic stenosis site was found in a major cerebral artery, in representative case 8 of an example according to one embodiment of the present invention.FIG. 10 is an explanatory diagram showing an example of a head CT angiography image acquired in representative case 8 of an example according to one embodiment of the present invention.

[0014] An embodiment of the present invention will be described below, although the present invention is not limited to this embodiment.

[0015] As one aspect, the present embodiment includes a method for determining the cause and / or treatment policy of acute cerebral infarction, which uses as an index an acute-chronic mismatch value (hereinafter referred to as "AC mismatch value") that represents the difference or ratio between a representative value representing the time to reach maximum concentration of a contrast agent and a representative value representing the mean transit time of the contrast agent, both of which are obtained from cerebral perfusion image data of a patient who has developed acute cerebral infarction (hereinafter referred to as "this method").

[0016] That is, the inventors of the present invention have intensively studied technical means for determining the cause and / or treatment policy of acute cerebral infarction, and as a result have independently found that the difference or ratio between the peak concentration time and the mean transit time, which are cerebral perfusion parameters, is associated with the presence of chronic stenosis in the major cerebral arteries of patients who have developed acute cerebral infarction, and have completed the present invention. The major cerebral arteries are arteries that supply blood to the cerebrum, cerebellum, or brainstem, and include the internal carotid artery, anterior cerebral artery, middle cerebral artery, posterior cerebral artery, vertebral artery, and basilar artery.

[0017] Here, the patients to whom this method is applicable are those who have developed acute cerebral infarction, and more specifically, for example, patients who have developed acute cerebral infarction, visit a medical institution, and then have cerebral perfusion image data obtained.

[0018] This method may also be used for patients with perfusion mismatch, i.e., patients with a mismatch between the volume of the ischemic core region and the volume of the perfusion delayed region in cerebral perfusion images acquired after the onset of acute cerebral infarction. Patients with a mismatch between the ischemic core region and the perfusion delayed region can be expected to benefit from reperfusion therapy.

[0019] Here, the ischemic core region is identified as the central region of the delayed perfusion region in brain tissue in a cerebral perfusion image, where recovery is not expected. On the other hand, the region of the delayed perfusion region in a cerebral perfusion image, which is peripheral to the ischemic core region and has a reduced blood flow but may be recoverable by early resumption of blood flow, i.e., the recoverable delayed perfusion region, is also called the penumbra region.

[0020] The ischemic core region and the penumbra region are identified, for example, from cerebral perfusion parameters. That is, the ischemic core region is identified, for example, by cerebral blood volume (CBF), which is a cerebral perfusion parameter that indicates cerebral blood flow. Specifically, when the CBF of a target region of the brain (e.g., a specific region in one of the left or right hemispheres of the cerebrum) is less than 30% of the CBF of a normal region of the brain (e.g., a region of the left or right hemisphere of the cerebrum where blood flow is normal, not including the target region), the target region is identified as the ischemic core region. Furthermore, the penumbra region is identified, for example, as a region other than the ischemic core region, where Tmax, a cerebral perfusion parameter that indicates the time it takes for the concentration of a contrast agent in brain tissue to reach its maximum value, exceeds 6 seconds.

[0021] The AC mismatch value used as an index in this method is obtained by analyzing a patient's cerebral perfusion image, as described below. The analysis of the cerebral perfusion image is preferably performed using a computer installed with an image analysis program.

[0022] Therefore, this embodiment includes, as another aspect, an apparatus for determining the cause and / or treatment plan of acute cerebral infarction (hereinafter referred to as "this apparatus"). Furthermore, this embodiment includes, as yet another aspect, a program for determining the cause and / or treatment plan of acute cerebral infarction (hereinafter referred to as "this program").

[0023] That is, at least some of the steps included in the method are preferably performed using the apparatus, and the program causes a computer to perform at least some of the steps included in the method.

[0024] Therefore, the following description will mainly focus on an example of the present embodiment, in which the method is implemented using the device including a computer on which the program is installed. Note that the program may be a computer program, a computer program product, or a non-transitory tangible computer-readable recording medium that includes instructions that, when executed by the computer, cause the computer to execute at least some of the steps included in the method.

[0025] 1 shows an example of the main hardware configuration of the device 10. In the example shown in FIG. 1, the device 10 includes a storage unit 11, a control unit 12, a display unit 13, an input unit 14, and a communication unit 15. The device 10 is not particularly limited as long as it can achieve the effects of the present invention, but is preferably a computer. That is, the device 10 includes, for example, a personal computer, a smartphone, a tablet terminal, or a wearable terminal.

[0026] The storage unit 11 is an element and / or device that stores programs and data necessary for processing executed by the device 10. That is, the storage unit 11 includes, for example, a volatile memory such as a RAM (random access memory) and a non-volatile memory such as a hard disk or flash memory.

[0027] The control unit 12 is one or more processors that execute the processing of the present device 10. The control unit 12 executes processing (e.g., arithmetic processing and image generation processing) corresponding to steps included in the present method, for example, based on a program stored in the storage unit 11 and / or a program supplied via a network (not shown). Furthermore, the control unit 12 executes processing using data stored in the storage unit 11, and / or stores data generated by the execution of processing in the storage unit 11, as necessary.

[0028] The display unit 13 is a display device that displays images or videos. That is, the display unit 13 includes, for example, a liquid crystal display or an organic electroluminescence (EL) display. The display unit 13 displays the images or videos generated by the control unit 12 so that the user of the device 10 can view them.

[0029] The input unit 14 is an input device that accepts input from a user of the device 10. That is, the input unit 14 includes, for example, a keyboard, a mouse, a touchpad, or a touch panel. The input unit 14 outputs data accepted from the user to the control unit 12.

[0030] The communication unit 15 is a communication device for transmitting and receiving data to and from other devices. That is, the communication unit 15 includes, for example, a communication interface for wired communication and / or a communication interface for wireless communication. The communication unit 15 outputs data received from other devices to the control unit 12. Furthermore, the communication unit 50 transmits data received from the control unit 12 to other devices.

[0031] Fig. 2 is a block diagram showing an example of main functions implemented by the device 10. Fig. 3 is a flow chart showing an example of steps performed in the method and / or steps that the program causes a computer to execute.

[0032] 2, the device 10 functionally includes a calculation processing unit 1, a comparison processing unit 2, and a display processing unit 3. In the example shown in Fig. 3, the program causes a computer to execute a calculation processing step S1 of calculating an AC mismatch value, a comparison processing step S2 of comparing the AC mismatch value with a predetermined criterion, and a display processing step S3 of displaying the results of the comparison.

[0033] As described above, in this method, the cause and / or treatment plan of acute cerebral infarction is determined using, as an index, the AC mismatch value, which represents the difference or ratio between a representative value representing the time to reach maximum concentration of the contrast agent (hereinafter, sometimes referred to as "T1") and a representative value representing the mean transit time of the contrast agent (hereinafter, sometimes referred to as "T2"), obtained from cerebral perfusion image data of a patient who has developed acute cerebral infarction.

[0034] Here, the present method may include calculating an AC mismatch value from the representative values ​​T1 and T2. In this regard, the present device 10 includes a calculation processing unit 1 that calculates an AC mismatch value representing the difference or ratio between the representative values ​​T1 and T2 from cerebral perfusion image data of a patient who has developed acute cerebral infarction, as shown in Fig. 2. Furthermore, the present program causes a computer to execute a calculation processing step S1 that calculates an AC mismatch value representing the difference or ratio between the representative values ​​T1 and T2 from cerebral perfusion image data of a patient who has developed acute cerebral infarction, as shown in Fig. 3.

[0035] The method for acquiring cerebral perfusion image data is not particularly limited as long as the effects of the present invention can be obtained. For example, computed tomography (CT) (more specifically, CT-perfusion (CTP)) or magnetic resonance imaging (MRI) (more specifically, MR-perfusion (MRP)) is preferably used.

[0036] Specifically, for example, a contrast agent is administered to the blood vessels of a patient, and the flow of the contrast agent in the patient's brain tissue is then measured using a CT or MRI device, thereby obtaining brain perfusion image data of the patient.

[0037] The cerebral perfusion image data thus obtained is data for generating a cerebral perfusion image, and includes data representing changes in the concentration of a contrast agent over time for each of a plurality of cross sections of the patient's brain. As the contrast agent used to acquire the cerebral perfusion image data, for example, an iodine contrast agent is preferably used in the CT perfusion method, and a gadolinium contrast agent is preferably used in the MR perfusion method.

[0038] The device 10 may acquire the cerebral perfusion image data from a cerebral perfusion image measuring device (e.g., a CT device or an MRI device) via the communication unit 15, from another device such as a computer connected to the measuring device, or from the user of the device 10 via the input unit 14.

[0039] The device 10 stores the acquired cerebral perfusion image data in the storage unit 11. The display processing unit 3 of the device 10 renders the cerebral perfusion image data to generate a cerebral perfusion image, which can be displayed on the display unit 13.

[0040] The AC mismatch value is calculated using a representative value T1 representing the time to reach maximum concentration of the contrast agent and a representative value T2 representing the mean transit time of the contrast agent. The time to reach maximum concentration of the contrast agent is obtained as the time from the start of measurement of the elapsed time after administration of the contrast agent (typically, a bolus administration) to the patient to the time when the concentration of the contrast agent in the patient's brain tissue reaches its maximum value in the acquisition of brain perfusion image data of the patient.

[0041] The time to maximum concentration is obtained for each unit region (e.g., a region corresponding to one of the pixels constituting a cerebral perfusion image) in a specific cerebral tissue cross-section of a patient. That is, the cerebral perfusion image data includes data on multiple cerebral perfusion images acquired at multiple measurement times for each of multiple cerebral tissue cross-sections, and the data on the multiple cerebral perfusion images includes the time to maximum concentration in each unit region corresponding to each of the multiple pixels constituting each cerebral perfusion image.

[0042] The time to maximum concentration is not particularly limited as long as it represents the time until the concentration of the contrast agent in brain tissue reaches its maximum value. For example, the Tmax value or the TTP (time to peak) value used as a cerebral perfusion parameter is preferably used, and the Tmax value is particularly preferably used.

[0043] The Tmax value is obtained, for example, as the time (seconds) until the contrast agent concentration reaches its maximum value in a transfer function (also called a residual function) obtained by deconvolution from a concentration function (also called a time-concentration curve) representing the change in contrast agent concentration over time in a patient's brain tissue and a concentration function (also called an arterial input function) representing the change in contrast agent concentration over time in the patient's normal arteries. The TTP value is obtained, for example, as the time (seconds) until the contrast agent concentration reaches its maximum value in the time-concentration curve representing the change in contrast agent concentration over time in the patient's brain tissue. In other words, the Tmax value can also be said to be the TTP value in the residual function.

[0044] The mean transit time of a contrast agent is obtained as the average time it takes for a contrast agent (typically, a contrast agent bolus) administered to a patient to pass through the patient's brain tissue when acquiring brain perfusion image data of the patient.

[0045] Like the time to maximum concentration, this mean transit time is also obtained for each unit region in a specific brain tissue cross-section of a patient. That is, the brain perfusion image data includes data on multiple brain perfusion images acquired at multiple measurement times for each of multiple brain tissue cross-sections, and the data on the multiple brain perfusion images includes the mean transit time in a unit region corresponding to each of the multiple pixels constituting each brain perfusion image.

[0046] The mean transit time is not particularly limited as long as it represents the average time it takes for a contrast agent to pass through brain tissue, but for example, the mean transit time (MTT) value used as a cerebral perfusion parameter is preferably used. The MTT value is obtained as the time (seconds) to the center of gravity of a transfer function (residual function) obtained by deconvolution from the time-density curve of the brain tissue and the arterial input function.

[0047] The device 10 may acquire the maximum concentration arrival time and / or mean transit time from a cerebral perfusion image measuring device (e.g., a CT device or an MRI device) via the communication unit 15, from another device such as a computer connected to the measuring device, or from the user of the device 10 via the input unit 14.

[0048] The calculation processing unit 1 of the device 10 may also calculate the maximum concentration arrival time and / or the mean transit time based on the cerebral perfusion image data. The calculation process of the maximum concentration arrival time and the mean transit time is preferably performed using, for example, an algorithm employed in commercially available brain image analysis software or an algorithm similar thereto. An example of commercially available brain image analysis software is iSchemaViewRAPID (iSchemaView Inc.), which is also used in the examples described below. The device 10 stores the acquired or calculated maximum concentration arrival time and / or the mean transit time in the memory unit 11.

[0049] The display processing unit 3 of the present device 10 may display a cerebral perfusion image showing the maximum concentration arrival time (e.g., a maximum concentration arrival time map showing the distribution of the maximum concentration arrival time in a brain tissue cross section, preferably a Tmax map or a TTP map, particularly preferably a Tmax map) and / or a cerebral perfusion image showing the mean transit time (e.g., a mean transit time map showing the distribution of the mean transit time in a brain tissue cross section, preferably an MTT map) based on the cerebral perfusion image data including the maximum concentration arrival time and / or the mean transit time.

[0050] That is, in this case, the display processing unit 3 of the present device 10 displays a cerebral perfusion image showing the time to maximum concentration and / or a cerebral perfusion image showing the mean transit time on the display unit 13. As a result, the user of the present device 10 can visually confirm the distribution of the time to maximum concentration and / or the mean transit time in the cross section of the patient's brain tissue based on the cerebral perfusion image displayed on the display unit 13.

[0051] The representative value T1 of the maximum concentration arrival time used to calculate the AC mismatch value is not particularly limited as long as it is a value that appropriately represents the magnitude of the maximum concentration arrival time in relation to the representative value T2 of the corresponding mean transit time. For example, it may be the sum of the maximum concentration arrival times (e.g., Tmax values ​​or TTP values, preferably Tmax values) of multiple pixels that make up part or all of the cerebral perfusion image (specifically, part or all of the regions of the cerebral tissue cross section depicted in the cerebral perfusion image), the average value (e.g., the average value obtained by dividing the sum of the maximum concentration arrival times of multiple pixels by the number of such pixels), the median, or a value obtained by applying addition, subtraction, multiplication, or division to any of these values ​​for the purpose of correction, simplification, etc.

[0052] The representative value T2 of the mean transit time used to calculate the AC mismatch value is not particularly limited as long as it is a value that appropriately represents the magnitude of the mean transit time in relation to the representative value T1 of the corresponding maximum concentration arrival time. For example, it may be the sum, average, or median of the mean transit times (e.g., MTT values) of multiple pixels that make up part or all of the cerebral perfusion image, or a value obtained by performing addition, subtraction, multiplication, or division on any of these values ​​for the purpose of correction, simplification, etc.

[0053] The device 10 may acquire the representative values ​​T1 and / or T2 from a cerebral perfusion image measuring device (e.g., a CT device or an MRI device) via the communication unit 15, from another device such as a computer connected to the measuring device, or from the user of the device 10 via the input unit 14.

[0054] The method may include calculating a representative value T1 and / or a representative value T2. In this regard, the calculation processing unit 1 of the apparatus 10 may calculate the representative values ​​T1 and / or T2 based on the cerebral perfusion image data. In this case, the calculation processing unit 1 calculates, as the representative values ​​T1 and / or T2, for example, the sum, average, or median of the maximum concentration arrival times and / or mean transit times of multiple pixels constituting a part or all of the cerebral perfusion image, or a value obtained by performing addition, subtraction, multiplication, or division on any of these values ​​for the purpose of correction, simplification, etc.

[0055] Furthermore, the display processing unit 3 of the present device 10 may display the representative values ​​T1 and / or T2 calculated by the calculation processing unit 1. That is, in this case, the display processing unit 3 of the present device 10 causes an image including the representative values ​​T1 and / or T2 to be displayed on the display unit 13. As a result, the user of the present device 10 can visually confirm the representative values ​​T1 and / or T2 used to calculate the AC mismatch value.

[0056] The representative values ​​T1 and / or T2 used in calculating the AC mismatch value may be representative values ​​of the maximum concentration arrival time and / or the mean transit time of a region of interest set in the cerebral perfusion image. In this case, the representative values ​​T1 and / or T2 are obtained as representative values ​​of the maximum concentration arrival time and / or the mean transit time of a plurality of pixels constituting the region of interest in the cerebral perfusion image (specifically, an image region corresponding to a portion of the brain tissue depicted in the cerebral perfusion image).

[0057] The region of interest set in the cerebral perfusion image is not particularly limited as long as the effects of the present invention can be obtained. For example, it is preferable that the region of interest include part or all of the ischemic core region and part or all of the penumbra region in the brain tissue cross section depicted in the cerebral perfusion image, and it is particularly preferable that the region of interest include at least part or all of the penumbra region.

[0058] The method for setting a region of interest in a cerebral perfusion image is not particularly limited as long as the effects of the present invention can be obtained. For example, it is preferable to set a region in a cerebral perfusion image (maximum concentration arrival time map) showing the distribution of maximum concentration arrival times in a cross section of brain tissue, where the maximum concentration arrival time is equal to or greater than a predetermined threshold, as the region of interest.

[0059] Specifically, for example, among the brain tissue cross sections depicted on the maximum concentration arrival time map, a region in which the maximum concentration arrival time (e.g., Tmax value) is 6 seconds or more, preferably 8 seconds or more, more preferably 10 seconds or more, and particularly preferably 12 seconds or more is set as a region of interest. Note that such a region in which the maximum concentration arrival time is equal to or greater than a predetermined threshold (e.g., any of the above thresholds) may be identified as a perfusion abnormality region.

[0060] The region of interest is preferably set using an algorithm employed in commercially available brain image analysis software, or a similar algorithm, such as MIPAV (Medical Image Processing, Analysis, and Visualization, National Institutes of Health, USA), which is also used in the examples described below.

[0061] The device 10 may acquire cerebral perfusion image data including data identifying the region of interest from another device, such as a computer connected to a cerebral perfusion image measurement device (e.g., a CT device or an MRI device), via the communication unit 15, or may acquire the data from the user of the device 10 via the input unit 14.

[0062] The calculation processing unit 1 of the apparatus 10 calculates an AC mismatch value representing the difference or ratio between the representative value T1 and the representative value T2 in a region of interest based on cerebral perfusion image data including data identifying the region of interest. That is, the calculation processing unit 1 calculates, as the representative values ​​T1 and / or T2, for example, the sum, average, or median of the maximum concentration arrival time and / or mean transit time of multiple pixels constituting a region of interest that is part of the cerebral perfusion image, or a value obtained by performing addition, subtraction, multiplication, or division on any of these values ​​for the purpose of correction, simplification, etc.

[0063] The display processing unit 3 of the present device 10 may display, on the display unit 13, a cerebral perfusion image in which the region of interest has been set, based on data identifying the region of interest received from the user via the input unit 14, so that the image can be viewed by the user.

[0064] The representative values ​​T1 and / or T2 used to calculate the AC mismatch value may be obtained from cerebral perfusion image data of one brain tissue cross section, or may be obtained from cerebral perfusion image data of multiple brain tissue cross sections.

[0065] When using the representative values ​​T1 and / or T2 obtained from the cerebral perfusion image data of one brain tissue cross section, the criteria for selecting the one brain tissue cross section are not particularly limited as long as the effects of the present invention can be obtained. For example, it is possible to select one brain tissue cross section that has the widest abnormal perfusion region (e.g., a region in which the maximum concentration arrival time is equal to or greater than a predetermined threshold (e.g., any of the thresholds mentioned above)) from among multiple brain tissue cross sections.

[0066] When using representative values ​​T1 and / or T2 obtained from cerebral perfusion image data of multiple brain tissue cross sections, the criteria for selecting the multiple brain tissue cross sections are not particularly limited as long as the effects of the present invention can be obtained. For example, it is preferable to select multiple brain tissue cross sections including one or more brain tissue cross sections selected by the same criteria as those for selecting one brain tissue cross section described above.

[0067] The AC mismatch value is obtained as a value representing the difference (i.e., T1-T2 or T2-T1) or ratio (i.e., T1 / T2 or T2 / T1) between a representative value T1 representing the time to reach maximum concentration of the contrast agent and a representative value T2 representing the average transit time of the contrast agent.

[0068] That is, when the AC mismatch value is a value representing the difference between T1 and T2, the AC mismatch value may be the difference between T1 and T2 (for example, the difference between the Tmax value or the TTP value and the MTT value, preferably the difference between the Tmax value and the MTT value) itself, or may be a value obtained by performing addition, subtraction, multiplication, or division on the difference, as long as it is a value that substantially represents the difference.

[0069] Furthermore, when the AC mismatch value is a value representing the ratio between T1 and T2, the AC mismatch value may be the ratio between T1 and T2 (for example, the ratio between the Tmax value or the TTP value and the MTT value, preferably the ratio between the Tmax value and the MTT value) itself, or may be a value obtained by performing addition, subtraction, multiplication, or division on the ratio, as long as it is a value that substantially represents the ratio.

[0070] Specifically, for example, in the Examples described later, the AC mismatch value used was a value (T1 / T2 value) obtained by dividing a representative value T1 of the time to maximum concentration (specifically, the sum, average, or median of the Tmax values) by a representative value T2 of the mean transit time (specifically, the sum, average, or median of the MTT values), or a value ((T1-T2) / T2 value) obtained by dividing the difference obtained by subtracting the representative value T2 from the representative value T1 by the representative value T2.

[0071] Here, the T1 / T2 value is an example of an AC mismatch value that represents the ratio between the representative value T1 and the representative value T2. The (T1-T2) / T2 value is an example of an AC mismatch value that represents the difference between the representative value T1 and the representative value T2 (specifically, a value obtained by dividing the difference). The (T1-T2) / T2 value is synonymous with "(T1 / T2)-1," and therefore can also be said to be an example of an AC mismatch value that represents the ratio between the representative value T1 and the representative value T2 (specifically, a value obtained by subtracting the ratio).

[0072] The calculation processing unit 1 of the device 10 executes a process (calculation process S1 in FIG. 3 ) of calculating an AC mismatch value that represents the difference or ratio between the representative values ​​T1 and T2. The display processing unit 3 of the device 10 also executes a process (display process S3 in FIG. 3 ) of displaying the AC mismatch value calculated by the calculation processing unit 1. That is, the display processing unit 3 of the device 10 displays an image including the AC mismatch value on the display unit 13. In this case, the user of the device 10 can visually confirm the AC mismatch value.

[0073] The display processing unit 3 of the device 10 may also display the AC mismatch value and a predetermined judgment criterion (described later) to be compared with the AC mismatch value. In this case, the display processing unit 3 of the device 10 displays an image including the AC mismatch value and the judgment criterion on the display unit 13. As a result, the user of the device 10 can visually confirm the AC mismatch value and the judgment criterion.

[0074] In this method, as demonstrated in the examples described below, by using the AC mismatch value as an index, it is possible to effectively determine the cause of acute cerebral infarction that a patient has developed and / or the treatment policy.

[0075] That is, in this method, for example, the AC mismatch value obtained from the patient's cerebral perfusion image data is compared with a predetermined judgment criterion, and based on the result of the comparison, the cause and / or treatment plan of the acute cerebral infarction that the patient has developed is determined.

[0076] In this case, the comparison processing unit 2 of the device 10 compares the AC mismatch value with a predetermined criterion and generates comparison result data representing the result of the comparison (comparison process S2 in FIG. 3). The program also causes a computer to execute a comparison process step (comparison process S2 in FIG. 3) of comparing the AC mismatch value with a predetermined criterion and generating comparison result data representing the result of the comparison.

[0077] The criteria for comparison with the AC mismatch value are not particularly limited as long as the effects of the present invention are obtained, and can be appropriately determined, for example, by statistically analyzing the AC mismatch values ​​obtained for multiple patients and information regarding the cause and / or treatment results of acute cerebral infarction obtained for the multiple patients.

[0078] A preferred criterion for determining the AC mismatch value is, for example, whether the AC mismatch value is within a predetermined numerical range, i.e., whether the AC mismatch value is equal to or greater than a predetermined lower limit, whether it is equal to or less than a predetermined upper limit, or whether it is within a numerical range specified by a predetermined lower limit and upper limit.

[0079] Specifically, in the Examples described below, by statistically analyzing AC mismatch values ​​obtained for a plurality of patients and information obtained for the plurality of patients as to whether or not chronic stenosis is present in the cerebral major arteries, it was found that the following are useful criteria for determining the cause and / or treatment policy of acute cerebral infarction that a patient has developed: whether or not the AC mismatch value (i.e., T1 / T2 value) obtained by dividing a representative value T1 representing the time to maximum concentration by a representative value T2 representing the mean transit time is 1.2 or greater; and whether or not the AC mismatch value (i.e., (T1-T2) / T2 value) obtained by subtracting the representative value T2 from the representative value T1 and dividing the difference obtained by the representative value T2 is 0.2 or greater.

[0080] According to the results of independent studies conducted by the inventors of the present invention, in patients with chronic stenosis in the major cerebral arteries, the maximum concentration time tends to be longer than the mean transit time. Therefore, for example, the larger the difference obtained by subtracting the mean transit time from the maximum concentration time, and / or the larger the ratio obtained by dividing the maximum concentration time by the mean transit time, the higher the possibility of the presence of chronic stenosis in the major cerebral arteries.

[0081] In fact, in the examples described below, patients whose T1 / T2 value, which is an example of an AC mismatch value, is equal to or greater than a predetermined threshold value (specifically, 1.2) and patients whose (T1-T2) / T2 value, which is another example of an AC mismatch value, is equal to or greater than a predetermined threshold value (specifically, 0.2) were found to have chronic stenosis in their major cerebral arteries, while patients whose T1 / T2 value and (T1-T2) / T2 value were less than the threshold values ​​were found to have no chronic stenosis in their major cerebral arteries.

[0082] The criteria used in the present method may differ depending on the population (i.e., patient population) to be subjected to statistical analysis, and therefore it is preferable to determine the criteria appropriately depending on the population to which the present method is applied.

[0083] The comparison result data generated by the comparison processing unit 2 of the present device 10 includes the result of comparing the AC mismatch value with the judgment criterion. That is, the comparison processing unit 2 generates comparison result data indicating, for example, that the AC mismatch value satisfies the judgment criterion (e.g., that the AC mismatch value is within a predetermined numerical range), or that the AC mismatch value does not satisfy the judgment criterion (e.g., that the AC mismatch value is not within the predetermined numerical range).

[0084] The display processing unit 3 of the present device 10 may display the comparison result between the AC mismatch value and the judgment criterion based on the comparison result data generated by the comparison processing unit 2 (display processing S3 in FIG. 3). That is, in this case, the present program causes the computer to execute a step of displaying the comparison result between the AC mismatch value and the judgment criterion based on the comparison result data generated by the comparison processing unit 2.

[0085] Specifically, the display processing unit 3 of the device 10 displays an image including the comparison result between the AC mismatch value and the judgment criterion (for example, whether or not the AC mismatch value satisfies the judgment criterion, more specifically, whether or not the AC mismatch value is within a predetermined numerical range) on the display unit 13. As a result, the user of the device 10 can visually confirm the comparison result between the AC mismatch value and the judgment criterion.

[0086] The cause and / or treatment policy of acute cerebral infarction determined by this method is not particularly limited as long as it provides information useful for diagnosing and / or treating the patient, such as predicting the patient's disease type, predicting the risk of pathology, and formulating a treatment strategy.

[0087] Acute cerebral infarction generally occurs due to acute occlusion of a major cerebral artery. However, acute occlusion that causes acute cerebral infarction can be classified into acute occlusion occurring in a part of the major cerebral artery that does not have chronic stenosis, and acute occlusion occurring in a part of the major cerebral artery that has had chronic stenosis before the onset of the acute cerebral infarction.

[0088] In this regard, if the acute cerebral infarction that a patient has developed is caused by acute occlusion of a chronic stenosis site that existed before the onset of the acute cerebral infarction, it becomes necessary to also treat the chronic stenosis site when treating the acute cerebral infarction.

[0089] However, it has been difficult to determine from cerebral perfusion images whether a patient's acute cerebral infarction is caused by acute occlusion of a major cerebral artery at a site of chronic stenosis that existed before the onset of the acute cerebral infarction.

[0090] For this reason, for example, after treatment for acute cerebral infarction has begun, the presence of a chronic stenotic area may become apparent, and as a result, treatment for the chronic stenotic area may need to be prepared and implemented quickly, forcing a change in treatment plan.

[0091] In response to this, the inventors of the present invention, as demonstrated in the Examples described below, have independently discovered that, by statistically analyzing AC mismatch values ​​obtained for multiple patients and information obtained for the multiple patients on whether or not chronic stenosis was present in the major cerebral arteries, there is a certain correlation between the results of comparing the AC mismatch value with a predetermined judgment criterion, the possibility that the cause of the acute cerebral infarction that the patient developed is related to chronic stenosis, and the need to consider the presence of chronic stenosis in the treatment of the acute cerebral infarction.

[0092] Therefore, in this method, the AC mismatch value is compared with a predetermined judgment criterion, and based on the results of the comparison, it may be determined whether: (a) the cause of the acute cerebral infarction that the patient has developed is possibly related to chronic stenosis; and / or (b) the need to consider the presence of a chronic stenosis site in the treatment of the patient's acute cerebral infarction.

[0093] In this case, the comparison processing unit 2 of the present device 10 compares the AC mismatch value with the judgment criteria, and based on the results of the comparison, generates comparison result data including: (a) judgment result data indicating the possibility that the cause of the acute cerebral infarction suffered by the patient is related to chronic stenosis; and / or (b) judgment result data indicating the need to consider the presence of chronic stenosis in the treatment of the patient's acute cerebral infarction.

[0094] The program also causes the computer to execute a comparison processing step (comparison processing S2 in FIG. 3 ) of comparing the AC mismatch value with a judgment criterion and generating comparison result data including the judgment result data (a) above and / or the judgment result data (b) above based on the result of the comparison.

[0095] The display processing unit 3 of the present device 10 may display the comparison result including the determination result indicating the above (a) and / or (b) based on the comparison result data generated by the comparison processing unit 2 (display processing S3 in FIG. 3). That is, in this case, the present program causes the computer to execute the step of displaying the comparison result including the determination result indicating the above (a) and / or (b).

[0096] Specifically, the display processing unit 3 of the device 10 displays on the display unit 13 an image indicating (a) the possibility that the cause of the acute cerebral infarction that the patient has developed is related to chronic stenosis, and / or (b) the need to consider the presence of a chronic stenotic area in treating the acute cerebral infarction that the patient has developed. In this case, the user of the device 10 can visually confirm the determination result indicating the above (a) and / or (b).

[0097] Here, as demonstrated in the Examples described below, the inventors of the present invention have independently discovered, by statistically analyzing AC mismatch values ​​obtained for multiple patients and information obtained for the multiple patients as to whether or not chronic stenosis was present in the major cerebral arteries, that if the AC mismatch value satisfies a predetermined criterion, the cause of the acute cerebral infarction that the patient developed is highly likely to be related to chronic stenosis, and therefore, that it is highly necessary to take into account the presence of a chronic stenotic area when treating the acute cerebral infarction.

[0098] Therefore, in this method, the AC mismatch value is compared with a predetermined judgment criterion, and when the AC mismatch value satisfies the judgment criterion (for example, when the AC mismatch value is within a predetermined numerical range), it may be judged that: (a) there is a high possibility that one of the causes of the patient's acute cerebral infarction was acute occlusion of a chronic stenosis site present in the patient's major cerebral artery (more specifically, a chronic stenosis site that existed in the patient's major cerebral artery before the patient developed the acute cerebral infarction); and / or (b) there is a high need to prepare treatment for the patient's acute cerebral infarction that assumes the presence of a chronic stenosis site in the patient's major cerebral artery.

[0099] In this case, the comparison processing unit 2 (FIG. 2) of the present device 10 compares the AC mismatch value with a predetermined judgment criterion, and when the AC mismatch value satisfies the judgment criterion, generates comparison result data including: (a) judgment result data indicating that one of the causes of the patient's acute cerebral infarction was likely acute occlusion of a chronic stenosis site in the patient's major cerebral artery; and / or (b) judgment result data indicating that, in treating the patient's acute cerebral infarction, it is highly necessary to prepare treatment that assumes the presence of a chronic stenosis site in the patient's major cerebral artery (comparison processing S2 in FIG. 3).

[0100] The program also causes the computer to execute a comparison processing step (comparison processing S2 in FIG. 3 ) of comparing the AC mismatch value with a predetermined judgment criterion, and generating comparison result data including the judgment result data (a) above and / or the judgment result data (b) above if the AC mismatch value satisfies the judgment criterion.

[0101] Furthermore, the display processing unit 3 of the present device 10 may display the comparison result including the determination results of (a) and / or (b) above based on the comparison result data generated by the comparison processing unit 2 (display processing S3 in FIG. 3). In this case, the present program causes the computer to execute the step of displaying the comparison result including the determination results of (a) and / or (b) above.

[0102] Specifically, the display processing unit 3 of the device 10 displays an image representing the determination results of (a) and / or (b) on the display unit 13. As a result, the user of the device 10 can visually confirm the determination results of (a) and / or (b).

[0103] In the present method in which the judgment is made as in (a) and / or (b) above when the AC mismatch value satisfies the judgment criterion, if the AC mismatch value does not satisfy the judgment criterion (for example, if the AC mismatch value is not within a predetermined numerical range), it may be judged that: (a') it is not highly likely that one of the causes of the patient's acute cerebral infarction was acute occlusion of a chronic stenosis site present in the patient's major cerebral artery; and / or (b') it is not highly necessary to prepare a treatment that assumes the presence of a chronic stenosis site in the patient's major cerebral artery in the treatment of the patient's acute cerebral infarction.

[0104] In this case, the display processing unit 3 of the present device 10 may display the comparison result including the determination results of (a') and / or (b') above, in the same way as when the AC mismatch value satisfies the determination criteria (display processing S3 in FIG. 3). Also, the present program causes the computer to execute a step of displaying the comparison result including the determination results of (a') and / or (b') above.

[0105] As mentioned above, acute cerebral infarction may be caused by acute occlusion of a chronic stenosis that existed in a patient's major cerebral arteries before the onset of the acute cerebral infarction. Patients with chronic stenosis in a major cerebral artery may be suffering from intracranial atherosclerotic disease (ICAD).

[0106] Therefore, in this method, if the AC mismatch value satisfies a predetermined criterion, it may be determined that the patient is highly likely to suffer from intracranial atherosclerosis, as in (a) above.

[0107] In this case, as the above (a), it may be determined that the acute cerebral infarction that the patient has developed is highly likely to be atherothrombotic cerebral infarction.

[0108] Furthermore, in this method, if the AC mismatch value does not satisfy the judgment criterion, it may be judged as (a') above that the patient is not likely to suffer from intracranial atherosclerosis; and / or that the acute cerebral infarction suffered by the patient is not likely to be atherothrombotic cerebral infarction.

[0109] Furthermore, as a treatment for acute cerebral infarction, thrombolytic drug administration therapy (e.g., intravenous injection therapy with recombinant tissue plasminogen activator (rt-PA)) and / or intravascular treatment (e.g., mechanical thrombectomy using an intravascular treatment device such as a stent retriever or a thrombus aspiration catheter) are preferably performed.

[0110] In this regard, when a patient has a chronically stenotic site in a major cerebral artery, it is preferable to simultaneously perform vasodilation therapy (e.g., balloon dilation using a balloon catheter and / or stent placement using a stent) to dilate the chronically stenotic site when performing mechanical thrombectomy on the patient.

[0111] Therefore, in this method, when the AC mismatch value satisfies a predetermined criterion, it may be determined that there is a high need to prepare treatment for a chronic stenotic site present in a major cerebral artery of the patient in endovascular treatment of the patient's acute cerebral infarction (for example, vasodilation therapy for dilating the chronic stenotic site (for example, balloon dilation using a balloon catheter and / or stent placement using a stent)).

[0112] Furthermore, in this method, if the AC mismatch value does not satisfy the judgment criterion, it may be judged as (b') above, that there is no high need to prepare treatment for the chronic stenosis site present in the patient's major cerebral artery in the endovascular treatment of the patient's acute cerebral infarction.

[0113] As described above, according to this method, the AC mismatch value obtained from cerebral perfusion image data is used as an index, making it possible to effectively determine the cause and / or treatment plan of acute cerebral infarction that a patient has developed.

[0114] Next, a specific example according to this embodiment will be described.

[0115] Eight patients with acute cerebral infarction visited the National Cerebral and Cardiovascular Center (Osaka, Japan) and underwent brain CT perfusion imaging, which was analyzed for each patient who provided written consent. Brain perfusion images were acquired using a CT scanner (Aquilion ONE GENESIS Edition (Canon Medical Systems), SOMATOM Force (Siemens Healthineers), or Revolution CT (GE HealthCare)) with iodine contrast medium.

[0116] The cerebral perfusion images were analyzed using a computer on which the commercially available brain image analysis program iSchemaViewRAPID (manufactured by iSchemaView) was installed.

[0117] [Representative Case 1] The patient in Representative Case 1 (hereinafter referred to as "Patient 1") was a female and 76 years old. According to the cerebral perfusion image data of Patient 1, the mismatch ratio (= V2 / V1) obtained by dividing the volume V1 of the "CBF < 30% region" by the volume V2 of the "Tmax > 6.0 s region" was equal to or greater than a predetermined value, indicating the presence of a perfusion mismatch.

[0118] Therefore, we analyzed the cerebral perfusion images of Patient 1. First, we displayed color maps of MTT and Tmax on a liquid crystal display as a cerebral perfusion image corresponding to the single brain tissue cross section with the widest region of abnormal perfusion, showing a Tmax of 6 seconds or more. Figure 4A shows the MTT map and Tmax map of Patient 1 in grayscale.

[0119] Next, using image analysis software, a region of interest (ROI) including the ischemic core region and penumbra region was set on the Tmax map. Figure 4B shows the Tmax map with the set ROI in grayscale. The area displayed in white on the right side of the Tmax map in Figure 4B is the ROI.

[0120] Thereafter, the region corresponding to the ROI set in the Tmax map as described above was also set as an ROI in the MTT map. Figure 4C shows the MTT map with the ROI set in grayscale. The region displayed in white in the MTT map on the left side of Figure 4C is the ROI.

[0121] Then, using a computer, the sum, mean, standard deviation, and median of the Tmax values ​​associated with the pixels constituting the ROI of the Tmax map, and the sum, mean, standard deviation, and median of the MTT values ​​associated with the pixels constituting the ROI of the MTT map were calculated.

[0122] Figure 4D shows the results of calculating the total ("Total Intensity"), mean ("Mean Intensity"), standard deviation ("Standard Deviation"), and median ("Median Intensity") of the Tmax and MTT values ​​of the pixels constituting the ROIs of the Tmax map ("Tmax" in the figure) and MTT map ("MTT" in the figure) for Patient 1.

[0123] FIG. 4D also shows, for each of the total value, average value, standard deviation value, and median value, the AC mismatch value (Tmax / MTT value) obtained by dividing the Tmax value by the MTT value ("Tmax / MTT" in the figure), and the AC mismatch value ((Tmax-MTT) / MTT value) obtained by dividing the difference obtained by subtracting the MTT value from the Tmax value by the MTT value ("(Tmax-MTT) / MTT" in the figure).

[0124] Furthermore, Figure 4D also shows the results of the assessment of whether or not chronic stenosis was found in the major cerebral arteries of Patient 1, based on head CT angiography (CTA) images (Figure 4E) acquired by CTA before the acquisition of cerebral perfusion images for Patient 1 ("Chronic Stenosis" in the figure).

[0125] As shown in Figure 4D, the Tmax / MTT values ​​calculated from the total, mean, and median values ​​for Patient 1 were all 1.4. The (Tmax-MTT) / MTT values ​​calculated from the total, mean, and median values ​​for Patient 1 were all 0.4. A chronic stenosis site (the site indicated by the arrow in Figure 4E) was found in the right internal carotid cerebral artery of Patient 1 ("Yes" in "Chronic Stenosis" in Figure 4D).

[0126] [Representative Case 2] The patient in Representative Case 2 (hereinafter referred to as "Patient 2") was female, 87 years old, and had perfusion mismatch. Figure 5A shows the MTT map and Tmax map of Patient 2 in grayscale. As with Representative Case 1 described above, Figure 5B shows the representative values ​​of Tmax and MTT, the results of calculating the AC mismatch value, and the evaluation results of whether or not a chronic stenosis site was found in the major cerebral arteries. Figure 5C shows a CTA image of Patient 2.

[0127] As shown in Figure 5B, for Patient 2, the Tmax / MTT values ​​calculated from the total and mean values ​​were both 1.9, and the Tmax / MTT value calculated from the median was 3.0. For Patient 2, the (Tmax-MTT) / MTT values ​​calculated from the total and mean values ​​were both 0.9, and the (Tmax-MTT) / MTT value calculated from the median was 2.0. A chronic stenosis site (the site indicated by the arrow in Figure 5C) was found in the left internal carotid cerebral artery of Patient 2 ("Yes" in "Chronic Stenosis" in Figure 5B).

[0128] [Representative Case 3] The patient in Representative Case 3 (hereinafter referred to as "Patient 3") was male, aged 86, and had perfusion mismatch. Figure 6A shows the MTT map and Tmax map of Patient 3 in grayscale. As with Representative Case 1 described above, Figure 6B shows the representative values ​​of Tmax and MTT, the results of calculating the AC mismatch value, and the evaluation results of whether or not a chronic stenosis site was found in the major cerebral arteries. Figure 6C shows a CTA image of Patient 3.

[0129] As shown in Figure 6B, for patient 3, the Tmax / MTT values ​​calculated from the total and mean values ​​were both 1.4, and the Tmax / MTT value calculated from the median was 1.5. For patient 3, the (Tmax-MTT) / MTT values ​​calculated from the total and mean values ​​were both 0.4, and the (Tmax-MTT) / MTT value calculated from the median was 0.5. A chronic stenosis site (the site indicated by the arrow in Figure 6C) was observed in the left internal carotid cerebral artery of patient 3 ("Yes" in "Chronic Stenosis" in Figure 6B).

[0130] [Representative Case 4] The patient in Representative Case 4 (hereinafter referred to as "Patient 4") was male, aged 83, and had perfusion mismatch. Figure 7A shows the MTT map and Tmax map of Patient 4 in grayscale. As with Representative Case 1 described above, Figure 7B shows the representative values ​​of Tmax and MTT, the calculated AC mismatch value, and the evaluation results of whether or not a chronic stenosis site was found in the major cerebral arteries. Figure 7C shows a CTA image of Patient 4.

[0131] As shown in Figure 7B, for Patient 4, the Tmax / MTT values ​​calculated from the total and mean values ​​were both 2.1, and the Tmax / MTT value calculated from the median was 2.5. For Patient 4, the (Tmax-MTT) / MTT values ​​calculated from the total and mean values ​​were both 1.1, and the (Tmax-MTT) / MTT value calculated from the median was 1.5. A chronic stenosis site (the site indicated by the arrow in Figure 7C) was observed in the left internal carotid cerebral artery of Patient 4 ("Yes" in "Chronic Stenosis" in Figure 7B).

[0132] Representative Case 5 The patient in Representative Case 5 (hereinafter referred to as "Patient 5") was female, 76 years old, and had perfusion mismatch. Figure 8A shows the MTT map and Tmax map of Patient 5 in grayscale. As with Representative Case 1, Figure 8B shows the representative Tmax and MTT values, the calculated AC mismatch value, and the evaluation results of whether or not a chronic stenosis was found in the major cerebral arteries. Figure 8C shows a CTA image of Patient 5.

[0133] As shown in Figure 8B, for patient 5, the Tmax / MTT values ​​calculated from the total and mean values ​​were both 1.2, and the Tmax / MTT value calculated from the median was 1.6. For patient 5, the (Tmax-MTT) / MTT values ​​calculated from the total and mean values ​​were both 0.2, and the (Tmax-MTT) / MTT value calculated from the median was 0.6. A chronic stenosis site (the site indicated by the arrow in Figure 8C) was observed in the left internal carotid cerebral artery of patient 5 ("Yes" in "Chronic Stenosis" in Figure 8B).

[0134] [Representative Case 6] The patient in Representative Case 6 (hereinafter referred to as "Patient 6") was male, 76 years old, and had perfusion mismatch. Figure 9A shows the MTT map and Tmax map of Patient 6 in grayscale. As with Representative Case 1 described above, Figure 9B shows the representative values ​​of Tmax and MTT values, the results of calculating the AC mismatch value, and the evaluation results of whether or not a chronic stenosis site was found in the cerebral major artery. Figure 9C shows a CTA image of Patient 6.

[0135] As shown in Figure 9B, for patient 6, the Tmax / MTT values ​​calculated from the total, mean, and median values ​​were all 1.1. Furthermore, for patient 6, the (Tmax-MTT) / MTT values ​​calculated from the total, mean, and median values ​​were all 0.1. Patient 6 had occlusion in the right internal carotid cerebral artery, but no chronic stenosis was observed in the major cerebral arteries ("No" in "Chronic Stenosis" in Figure 9B).

[0136] [Representative Case 7] The patient in Representative Case 7 (hereinafter referred to as "Patient 7") was male, 43 years old, and had perfusion mismatch. Figure 10A shows the MTT map and Tmax map of Patient 7 in grayscale. As with Representative Case 1 described above, Figure 10B shows the representative values ​​of Tmax and MTT, the results of calculating the AC mismatch value, and the evaluation results of whether or not a chronic stenosis site was found in the major cerebral arteries. Figure 10C shows a CTA image of Patient 7.

[0137] As shown in Figure 10B, for patient 7, the Tmax / MTT values ​​calculated from the total and mean values ​​were both 0.9, and the Tmax / MTT value calculated from the median was 0.8. For patient 7, the (Tmax-MTT) / MTT values ​​calculated from the total and mean values ​​were both -0.1, and the (Tmax-MTT) / MTT value calculated from the median was -0.2. Patient 7 had occlusion in the right middle cerebral artery, but no chronic stenosis was observed in the major cerebral arteries ("No" in "Chronic Stenosis" in Figure 10B).

[0138] [Representative Case 8] The patient in Representative Case 8 (hereinafter referred to as "Patient 8") was male, 55 years old, and had perfusion mismatch. Figure 11A shows the MTT map and Tmax map of Patient 8 in grayscale. As with Representative Case 1 described above, Figure 11B shows the representative values ​​of Tmax and MTT values, the results of calculating the AC mismatch value, and the evaluation results of whether or not a chronic stenosis site was found in the cerebral major artery. Figure 11C shows a CTA image of Patient 8.

[0139] As shown in Figure 11B, for patient 8, the Tmax / MTT values ​​calculated from the total and mean values ​​were both "1.0," and the Tmax / MTT value calculated from the median was "1.1." For patient 8, the (Tmax-MTT) / MTT values ​​calculated from the total and mean values ​​were both "0.0," and the (Tmax-MTT) / MTT value calculated from the median was "0.1." Patient 8 had occlusion in the left internal carotid artery, but no chronic stenosis was observed in the major cerebral arteries ("No" in "Chronic Stenosis" in Figure 11B).

Claims

1. A method for determining the cause and / or treatment plan of acute cerebral infarction, which uses an acute-chronic mismatch value, obtained from cerebral perfusion image data of a patient who has developed acute cerebral infarction, as an index, which represents the difference or ratio between a representative value representing the time to reach maximum concentration of a contrast agent and a representative value representing the mean transit time of the contrast agent.

2. The method according to claim 1, further comprising comparing the acute-chronic mismatch value with a predetermined criterion, and determining the cause and / or treatment plan of the acute cerebral infarction based on the result of the comparison.

3. The method of claim 2, wherein, based on the results of the comparison, the following is determined: (a) the possibility that the cause of the acute cerebral infarction in the patient is related to chronic stenosis; and / or (b) the need to consider the presence of a chronic stenosis site in the treatment of the acute cerebral infarction in the patient.

4. The method of claim 3, wherein when the acute-chronic mismatch value satisfies the judgment criteria, it is judged that: (a) one of the causes of the acute cerebral infarction in the patient was likely to be acute occlusion of a chronic stenosis site in the patient's major cerebral artery; and / or (b) in treating the acute cerebral infarction in the patient, it is highly necessary to prepare treatment that assumes the presence of a chronic stenosis site in the patient's major cerebral artery.

5. An apparatus for determining the cause and / or treatment plan of acute cerebral infarction, comprising a calculation processing unit that calculates an acute-chronic mismatch value representing the difference or ratio between a representative value representing the time to reach maximum concentration of a contrast agent and a representative value representing the mean transit time of the contrast agent from cerebral perfusion image data of a patient who has developed acute cerebral infarction.

6. The apparatus of claim 5, further comprising a comparison processor that compares the acute-chronic mismatch value with a predetermined criterion and generates comparison result data representing a result of the comparison.

7. The device described in claim 6, wherein the comparison processing unit generates the comparison result data based on the result of the comparison, the comparison result data including: (a) determination result data indicating the possibility that the cause of the acute cerebral infarction of the patient is related to chronic stenosis; and / or (b) determination result data indicating the need to consider the presence of a chronic stenosis site in treating the acute cerebral infarction of the patient.

8. The device described in claim 7, wherein, when the acute-chronic mismatch value satisfies the judgment criterion, the comparison processing unit generates the comparison result data including: (a) the judgment result data indicating that one of the causes of the acute cerebral infarction in the patient was likely to be acute occlusion of a chronic stenosis site in the patient's major cerebral artery; and / or (b) the judgment result data indicating that, in treating the acute cerebral infarction in the patient, it is highly necessary to prepare treatment that assumes that a chronic stenosis site exists in the patient's major cerebral artery.

9. A program for determining the cause and / or treatment plan of acute cerebral infarction, which causes a computer to execute a calculation processing step of calculating an acute-chronic mismatch value representing the difference or ratio between a representative value representing the time to reach maximum concentration of a contrast agent and a representative value representing the mean transit time of the contrast agent, from cerebral perfusion image data of a patient who has developed acute cerebral infarction.

10. The program according to claim 9, further causing the computer to execute a comparison processing step of comparing the acute-chronic mismatch value with a predetermined criterion and generating comparison result data representing the result of the comparison.

11. The program according to claim 10, which causes the computer to execute the comparison processing step of generating the comparison result data including, based on the result of the comparison: (a) judgment result data indicating the possibility that the cause of the acute cerebral infarction of the patient is related to chronic stenosis; and / or (b) judgment result data indicating the need to consider the presence of a chronic stenosis site in the treatment of the acute cerebral infarction of the patient.

12. The program of claim 11, which causes the computer to execute the comparison processing step of generating the comparison result data including, when the acute-chronic mismatch value satisfies the judgment criterion: (a) the judgment result data indicating that one of the causes of the acute cerebral infarction in the patient was likely to be acute occlusion of a chronic stenosis site in the patient's major cerebral artery; and / or (b) the judgment result data indicating that, in treating the acute cerebral infarction in the patient, it is highly necessary to prepare treatment that assumes that a chronic stenosis site exists in the patient's major cerebral artery.

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