JP6513365B2 - Medical image processing device - Google Patents

Description

  An embodiment as one aspect of the present invention relates to a medical image processing apparatus.

  In recent years, cerebral infarction is a particularly frequent disease among cerebrovascular disorders, often accompanied by sequelae such as motor disorders and higher brain dysfunction, and the quality of life (QOL) declines, bedridden and long-term The problem is an increase in medical expenses due to rehabilitation. In a cerebral infarction, the artery in the brain is clogged and occluded by a thrombus, etc., and the downstream tissue perfused in that artery loses its function due to a lack of blood flow (ischemia), and the tissue eventually got into ischemia. Is a disease that causes necrosis. The site where the tissue is thus necrotic due to ischemia is called an infarct.

  The cerebral infarction may be diagnosed by an X-ray CT (Computed Tomography) apparatus or an MRI (Magnetic Resonance Imaging) apparatus.

  Treatment of cerebral infarction requires treatment (hereinafter referred to as recanalization therapy) to remove the thrombus generated in the arteries of the brain and restore the blood flow of the ischemic brain tissue. In reperfusion therapy, a thrombolytic agent is administered systemically from a vein to dissolve and occlude a thrombus that has occluded an artery, or a catheter is sent into a cerebral blood vessel and the thrombolytic agent is released from its tip. There is a method of reconstituting a thrombus that occludes an artery or physically removing the thrombus.

  In particular, there is provided a technique for analyzing the local blood flow of the brain from an image acquired by an X-ray CT apparatus or an MRI apparatus (Patent Document 1). Xenon CT / CBF (Xe-enhanced CT) examination (patent document 2) which performs CT imaging using Xe gas (xenon gas) as a method of examining blood flow by X-ray CT apparatus, CVP (cerebral blood flow) There is known a CVP test (perfusion CT test) (Patent Document 3) for calculating parameters such as MTT (average transit time) and CBV (blood volume).

  When blood flow is restored by recurrent treatment, treatment is often completed immediately, leaving little aftereffects. However, reopening therapy is not only effective for treatment after a certain amount of time has passed since the onset of cerebral infarction, but it also causes massive intracerebral hemorrhage due to the inflow of blood into capillaries that are necrosis and decaying. May cause, often leading to death. In such cases, there are many cases where recovery is achieved by taking a rest therapy without treatment.

  In view of such a problem of reopening therapy, a time limit from onset to start of treatment by reopening therapy is provided, which is called a time window. However, the time window is a standard based on statistical knowledge, and there is also a problem that it can not be applied when the onset time of cerebral infarction is unknown. In addition, before performing treatment such as recanalization therapy, there are minimal steps necessary to start treatment, such as finding and transporting a patient, and explaining the diagnosis and treatment. Such procedures may not be completed within the time limit and reopening therapy may not be applicable. Furthermore, even when surgery can be performed within the time window, there are many cases in which cerebral infarction occurs and results in ineffective response or cases in which intracerebral hemorrhage occurs. In addition, there are many cases in which resuming therapy is performed and recovered at a time beyond the time window before the time window is defined.

  Such diversity is believed to be due to the remaining blood flow rather than the time from onset of the condition. That is, there are mixed cases where brain tissue is becoming necrotic even within the time window time limit and cases where brain tissue survives even if the time limit is exceeded. These differences are considered to be mainly caused by how much blood flow remains at the ischemic site.

JP 2008-100121 A JP-A-11-206754 JP 2005-095340 A

  However, it may not be easy to determine how to perform treatment even if only data obtained by measuring blood flow is observed.

  Therefore, it is desirable to provide information for determining the treatment to be taken for the cerebral infarction by visualizing the progress of the cerebral infarction in each part of the brain.

  The medical image processing apparatus according to the present embodiment receives local cerebral tissue blood flow, which is a local blood flow in the brain tissue of the subject calculated based on a medical image obtained by imaging the brain of the subject. A cerebral infarction index calculation unit for calculating a cerebral infarction index which quantifies the recoverability of the subject's brain tissue with time based on the input data of the local cerebral tissue blood flow input; It is characterized by having.

BRIEF DESCRIPTION OF THE DRAWINGS The conceptual block diagram which shows an example of the medical image processing apparatus which concerns on embodiment. 1 is a functional block diagram showing an example of a functional configuration of a medical image processing apparatus according to a first embodiment. 6 is a flowchart showing an example of the operation of the medical image processing apparatus according to the first embodiment. The figure explaining the cerebral infarction index computed based on the past clinical data. FIG. 8 is a view for explaining a display example of a first outcome forecast map of the medical image processing apparatus according to the first embodiment. FIG. 7 is a view for explaining a display example of a second outcome forecast map of the medical image processing apparatus according to the first embodiment. FIG. 9 is a functional block diagram showing an example of the functional configuration of a medical image processing apparatus according to the second embodiment. 9 is a flowchart showing an example of the operation of the medical image processing apparatus according to the second embodiment. FIG. 8 is a view for explaining a display example of a contradiction map of the medical image processing apparatus according to the second embodiment.

  Hereinafter, an embodiment of a medical image processing apparatus will be described with reference to the attached drawings.

(overall structure)
FIG. 1 is a conceptual block diagram showing an example of a medical image processing apparatus 100 according to the embodiment. As shown in FIG. 1, the medical image processing apparatus 100 includes a communication control device 10, a storage unit 20, a main control unit 30, a display unit 40, and an input unit 50. The medical image processing apparatus 100 is connected to the medical image unified management server 200 and the modality apparatus 300 via the communication control apparatus 10 via an electronic network. The communication control device 10 implements various communication protocols according to the network configuration. Here, the term "electronic network" refers to the entire information communication network using telecommunications technology, and includes a hospital backbone LAN, wireless / wired LAN, and the Internet network, as well as a telephone communication network, an optical fiber communication network, a cable communication network and satellites. Includes communication networks etc. The medical image processing apparatus 100 acquires data such as medical images from the medical image unified management server 200 or the modality apparatus 300 via an electronic network.

  The modality device 300 includes various medical image diagnostic devices such as an XeCT analysis device, an X-ray CT (Computed Tomography) device, an MRI (Magnetic Resonance Imaging) device, and a PET (Positron Emission Tomography) device.

  The program stored in the storage unit 20 is executed by the main control unit 30, whereby image processing such as calculation of a cerebral infarction index and generation of an outcome forecast map is performed.

  The storage unit 20 includes a storage medium such as a RAM and a ROM, and includes a storage medium readable by the main control unit 30, such as a magnetic or optical storage medium or a semiconductor memory, Some or all of the programs and data in these storage media may be configured to be downloaded via an electronic network.

  The display unit 40 is configured of a general display device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display, and displays an image according to the control of the main control unit 30.

  The input unit 50 is formed of, for example, a general input device such as a keyboard, a touch panel, a ten-key pad, and a mouse.

  Hereinafter, a method of calculating a cerebral infarction index which numerically estimates the recovery possibility for each part of the brain and mapping the recovery possibility for each part of the brain to generate an "outcome forecast map" is the first embodiment, the brain The second practice is to calculate the difference between the regional cerebral tissue blood flow observed in tissues and the regional cerebral blood flow observed in cerebral blood vessels, and generate a "contradiction map" that maps the differences for each site. It explains as a form.

First Embodiment
Hereinafter, a first embodiment for generating an outcome forecast map from a cerebral infarction index will be described.

(1) Configuration FIG. 2 is a functional block diagram showing an example of a functional configuration of the medical image processing apparatus 100 according to the first embodiment. As shown in FIG. 2, the medical image processing apparatus 100 includes a data input unit 21, a cerebral infarction index calculation unit 32, an outcome prediction unit 33, an outcome prediction map generation unit 34, a color assignment unit 35, and a display unit 40.

  In the above configuration, each function of the cerebral infarction index calculation unit 32, the outcome prediction unit 33, the outcome prediction map generation unit 34, and the color assignment unit 35 is performed by the main control unit 30 executing a program stored in the storage unit 20. It is a function to be realized.

The data input unit 21 receives a regional cerebral tissue blood flow distribution image that indicates the local blood flow in the subject's brain tissue calculated based on the medical image of the subject's brain. Regional Cerebral Blood Flow (rCBF) indicates the amount of blood flowing in one minute per 100 ml of brain tissue (unit: ml / min / 100 ml).
XeCT examination is one of the methods to obtain regional cerebral tissue blood flow distribution image. In XeCT examination, a subject is made to inhale Xe gas mixed with air, and Xe is carried by bloodstream, diffused and stored in brain tissue, and a series of images taken with X-ray CT apparatus and processes of being washed away The XeCT analyzer generates a regional cerebral tissue blood flow distribution image based on the data of the Xe concentration in blood at each time point when the imaging was performed. Since Xe gas diffuses into the brain tissue through the blood brain barrier (BBB), it can measure regional cerebral tissue blood flow by XeCT examination.

  The cerebral infarction index calculation unit 32 calculates a cerebral infarction index in which the recovery possibility with the passage of time of the brain tissue of the subject is quantified based on the input local cerebral tissue blood flow (rCBF). The cerebral infarction index is calculated from the elapsed time which is the time from the onset of the cerebral infarction in the subject to the present time and the regional cerebral tissue blood flow (rCBF). The specific calculation method of the cerebral infarction index will be described later.

  The outcome prediction unit 33 predicts the outcome of the subject's brain tissue based on whether the cerebral infarction index calculated at the current time exceeds a predetermined threshold. Further, a time when the cerebral infarction index exceeds a predetermined threshold is predicted, and a grace period which is a time from the current time to the predicted time is predicted. The method of predicting the outcome of the brain tissue of the subject will be described later.

  The outcome forecast map generation unit 34 generates, in real time, an outcome forecast map in which the value of the cerebral infarction index is a pixel value. Details of the outcome forecast map will be described later.

  The color allocator 35 allocates at least one color information of lightness, saturation, hue, and transparency to the pixel based on the value of the cerebral infarction index.

(2) Operation Hereinafter, the operation of calculating the cerebral infarction index and generating the outcome prediction map according to the first embodiment will be described.

  FIG. 3 is a flowchart showing an example of the operation of the medical image processing apparatus 100 according to the first embodiment.

  In ST101, the regional cerebral tissue blood flow (rCBF) is input to the data input unit 21.

  In ST103, the cerebral infarction index calculation unit 32 calculates a cerebral infarction index. The cerebral infarction index (hereinafter referred to as symbol index; unit is hour ml / min / 100 ml) is rCBF, the elapsed time from the subject's onset of cerebral infarction to the current time (hereinafter symbol T, unit is hour) The information is used to quantify the recoverability of each site of cerebral infarction from the information, and is calculated by the following equation with a as a constant.

index = (a-r CBF) T (1)

  The constant a indicates the minimum blood flow necessary for brain tissue survival, and is empirically said to be 20 (ml / min / 100 ml). The cerebral infarction index is a value indicating how much energy stock in brain tissue is lost. That is, by multiplying the elapsed time (T) by how much the blood flow is insufficient compared with the minimum blood flow (constant a), the above equation (1) loses only how much energy storage in brain tissue is Calculate (cerebral infarction index (index)). Therefore, index is a numerical value that changes with the passage of time. In the following description, it is assumed that a = 20 (ml / min / 100 ml).

  FIG. 4 is a diagram for explaining a cerebral infarction index calculated based on past clinical data. FIG. 4 is described in Touho H, Karasawa J, Evaluation of time-dependent thresholds of cerebral blood flow and transit time during the acute stage of cerebral embolism: a retrospective study, Surg Neurol. 1996 Aug; 46 (2): 135-45. It is a graph created based on the clinical data. The horizontal axis in FIG. 4 indicates the elapsed time taken from the onset to the reopening, that is, the reopening passing time (T). The vertical axis shows cerebral infarction index (index). The white circle "opened-no infarcted" in Fig. 4 shows the subject whose infarct did not occur as a result of reperfusion, and the black circle "opened-infarcted" was reopened but whose infarct occurred. Is shown. In addition, the white square “disruption-no infarction” in FIG. 4 indicates a subject who can not reopen, but no infarcted area has occurred, and the black square “disruption-infarct generation” can not be resumed and an infarcted area is generated. Shows a subject who has

  As shown by the distribution of white circles “opened-infarctionless” and black circles “opened-infarct development” in FIG. For example, in white circle 1 and black circle 1 indicated by arrows in FIG. 4, the cerebral infarction index is a broken line A in white circle 1 while both of the resuming times are about 3 hours (3 hours are in the time window) The black circle 1 is larger than the broken line A. In the white circle 1 and the black circle 1, even though the resumption passing time is also about 3 hours, the white circle 1 shows that the energy reserve in the brain tissue remains an amount necessary for survival and the brain tissue is recovered. It is considered that the infarcted area was generated because the amount required for survival was reduced.

  The broken line A shown in FIG. 4 is a straight line in which the cerebral infarction index shown in FIG. 4 is about 22 to 23 (hour ml / min / 100 ml). 22 to 23 (hour ml / min / 100 ml) is considered to be a numerical value indicating that the normal brain tissue is capable of anaerobically metabolizable energy, and is a boundary value empirically obtained from the distribution of cerebral infarction index. In the first embodiment, based on this boundary value, the recovery possibility for each region of the brain is predicted from the cerebral infarction index calculated from the rCBF of the subject (ST105), and an outcome forecast map is generated (ST107). .

  FIG. 5 is a view for explaining a display example of a first outcome forecast map of the medical image processing apparatus 100 according to the first embodiment. In FIG. 5, a case of cerebral ischemia caused by an embolism in the left carotid artery will be described as an example. The right half of FIG. 5 represents the cross section of the left hemisphere.

  In the window W1 of FIG. 5, a current time display T1, an outcome forecast map IMG1 at the current time, and a legend T2 are shown. In the current time display T1, "Forecast as of December 10, 2005 at 07:30" is displayed. The outcome forecast map IMG1 in FIG. 5 shows an image in which the value of the cerebral infarction index at the current time is a pixel value.

  The thinnest shaded area in the upper part of the legend T2 indicates the "cannot be a cerebral infarction" even if it can not be resumed. The shaded area shown in the upper part of the legend T2 in the outcome forecast map IMG1 of FIG. 5 indicates an area predicted to be “cannot be a cerebral infarction even if it can not be resumed”. This area is an area where the cerebral infarction index (index) has a negative value (index <0).

  Also, the shaded area in the middle of the legend T2 indicates the area "there is a grace period before resuming at the current time". The shaded area shown in the middle part of the legend T2 in the outcome prediction map IMG1 of FIG. 5 is an area predicted as "there is a grace period before resuming at the current time". This area is an area showing cerebral infarction index (index) 0 <index <22, and if the elapsed time (T) becomes larger than the above-mentioned formula (1), the area where cerebral infarction index exceeds the boundary value 22 will be It shows. That is, if it immediately resumes at this point, it does not become an infarct, but it is a part predicted to become an infarct over time. This area is considered to be generally consistent with the concept called ischemic penumbra.

  Furthermore, the shaded area shown at the bottom of the legend T2 indicates the area of "No grace time until restart at current time". The shaded area shown in the lower part of the legend T2 in the outcome prediction map IMG1 of FIG. 5 is an area predicted as “No grace period by reopen at the current time”. This area is an area where the cerebral infarction index (index) has a value larger than 22 (22 <index). That is, it is a part which is predicted to become an infarct even if it immediately resumes at this point, and is a part which is presumed to be already unrecoverable. It is also predicted that in this area there may be an intracerebral hemorrhage after recanalization if it is resumed.

  Thus, the outcome forecast map assists in the determination of treatment strategies at the present time. For example, if there is no area in the outcome forecast map that is determined to be "no grace time before reopening at the current time", it can be determined that the patient is likely to recover by reopening. On the other hand, if there is a region judged to be "no grace time before reopening at the current time", it is predicted that intracerebral hemorrhage will occur when resuming therapy is applied, so it is better to select a rehab therapy You can judge that it is good. In addition, since it is possible to spatially specify an area judged to be "no grace time before reopening at the current time", such area is avoided, and only blood vessels feeding the other areas are resumed. By doing this, it is possible to save only a part of the brain. For example, after using a catheter to artificially occlude a blood vessel branch feeding a region judged to be "no grace time by reopen at the current time" with a sponge-like embolic material, By resuming circulation of the blood vessel branches that control other areas, it is possible to resume blood flow in the recoverable area while avoiding intracerebral hemorrhage.

  As described above, the outcome prediction map is an image showing prediction of whether or not each part of the brain will become an infarct at the current time. Such an outcome forecast map may be indicated by color information such as lightness, saturation, hue and transparency. For example, an intuitively understandable image can be generated by displaying the upper part of the legend T2 in FIG. 4 in a color scale such as green for the interruption, yellow for the interruption, and red for the lower part. The color allocation unit 35 allocates color information to each pixel based on the value of the cerebral infarction index, and the outcome forecast map generation unit 34 produces a color scale outcome forecast map. In addition, since the outcome forecast map indicates the recoverability at the current time, it must be updated momentarily as time passes.

  FIG. 6 is a view for explaining a display example of a second outcome forecast map of the medical image processing apparatus 100 according to the first embodiment. FIG. 6 shows an example in which the outcome forecast map illustrated in FIG. 5 is further divided.

  In the window W2 of FIG. 6, a current time display T1, an outcome forecast map IMG2 at the current time, and a legend T3 are shown. The current time display T1 is the same as the current time display T1 of FIG. The outcome forecast map IMG2 in FIG. 6 is the outcome forecast map at the current time, and shows predictions classified in more detail.

  The first white from the top of the legend T3 in FIG. 6 indicates the region “within the normal range of blood flow volume”. The first white area from the top of the legend T3 in the outcome forecast map IMG2 in FIG. 6 indicates the area “within the normal range of blood flow”. In the outcome forecast map IMG2 of FIG. 6, the right hemisphere (left half of the figure) which is not affected by an embolism generated in the left carotid artery is shown as a region within the normal blood flow range. Whether or not the blood flow is within the normal range may be determined, for example, by comparing the value of rCBF with a predetermined threshold. For example, since rCBF of normal human gray matter is generally about 50 (ml / min / 100 ml), when the value of rCBF is 50 (ml / min / 100 ml) or more, “within the normal blood flow range” It may be determined that

  The second thinnest hatching from the top of the legend T3 in FIG. 6 indicates a legend of a region predicted to be “cannot be a cerebral infarction even if it can not be resumed”. The shaded area shown in the second row from the top of the legend T3 in the outcome forecast map IMG2 in FIG. 6 indicates the area predicted to be “cannot be a cerebral infarction even if it can not be resumed” . This region has a negative cerebral infarction index (index) (index <0). Such a region is a portion which is predicted not to become an infarct even if inhalation therapy is adopted without reopening.

  The third shaded area from the top of the legend T3 in FIG. 6 indicates the area of “2 hours or more of grace time until restart at current time”. That is, the index at the present time is obtained by Expression (1) based on the elapsed time T from the onset to the current time. The point in time when the index is 22 is the point in time when the elapsed time from onset is T ', which is calculated by the following equation (2).

22 = (a-rCBF) T '(2)
Therefore, the grace period Tm is
Calculated by

  The shaded area shown in the third row from the top of the legend T3 in the outcome forecast map IMG2 in FIG. 6 indicates the area predicted to be "2 hours or more of grace time before resuming at current time". ing. Although this area may become an infarct if it passes for 2 hours or more without reperfusion, it is an area predicted to have a grace period of at least 2 hours for reperfusion at the current time until reperfusion.

  The fourth diagonal line from the top of the legend T3 in FIG. 6 indicates the area of “1 to 2 hours of grace time before resuming at current time”. The shaded area shown in the fourth row from the top of the legend T3 in the outcome forecast map IMG2 in FIG. 6 indicates the area predicted to be “1 to 2 hours of grace time before resuming at current time”. ing. If this area is reopened within 1 hour from the present time, it will not become an infarct, and if it passes over 2 hours from now, it will be an infarct (it will of course become an infarct if reopened) Area.

  The fifth grid hatch from the top of the legend T3 in FIG. 6 shows the legend of the area predicted to be “less than 1 hour of grace time before resuming at current time”. The shaded area shown in the fifth row from the top of the legend T3 in the outcome forecast map IMG2 in FIG. 6 indicates the area predicted to be "less than 1 hour of grace time before resuming at current time". ing. This area does not become an infarct if it is reopened immediately at present, but it is an area predicted to become an infarct if reopened after an hour or more from the current (of course it becomes an infarct if it is not reopened) .

  The shaded area in the sixth row from the top of the legend T3 of FIG. 6 shows the legend of the area predicted to be "less than 0 hour of grace time before resuming at current time". The area where the sixth shaded area from the top of the legend T3 is displayed in the outcome forecast map IMG2 in FIG. 6 indicates an area predicted to be "less than 0 hour of grace time before resuming at current time". This area is an area that is predicted to become an infarct even if it immediately resumes at this time.

  The shaded area at the bottom of the legend T3 in FIG. 6 indicates the legend of the area predicted to be "Grace time until resuming at current time-(less than 5 hours)". The shaded area at the bottom of the legend T3 in the outcome forecast map IMG2 of FIG. 6 indicates an area predicted to be "less than grace time-5 hours before resuming at current time". This area may have been recovered if it was reopened at a considerable point before the current point (5 hours before the current point), but it indicates an area where the infarct has already occurred and the time has elapsed. That is, it is a region where it is predicted that intracerebral hemorrhage is likely to occur if reopening is performed after the current time.

  Possible intracerebral hemorrhage by resuming a blood vessel that has been feeding the area in which the shaded area at the sixth row from the top of the legend T3 in FIG. 6 and the shaded area at the bottom are displayed from the outcome forecast map IMG2 in FIG. 6 Can be judged to be dangerous. Thus, it can be determined that palliative therapy should be employed if such an area is present. Furthermore, because it is possible to identify the area where it is judged that there is a possibility of intracerebral hemorrhage when reopening blood vessels, avoid such areas and resume blood circulation only for the blood vessels feeding the other areas. It may be possible to adopt a treatment that

  According to the outcome prediction map as described above, the treatment can be intuitively selected quickly and flexibly according to the progress of the medical condition, or can be changed. For example, even if there is a region of “less than 1 hour grace period before reopening at the current time” in the outcome forecast map, if the catheter is already inserted in the progress of reopening procedure, immediately Since it is possible to release the thrombolytic agent for treatment, it can be judged that there is a high possibility that an infarct will not occur.

  On the other hand, if you are going to insert a catheter or administer a thrombolytic agent to a vein from now on, it is already necessary to recover the area of "less than 1 hour of grace time before resuming at current time". It can be judged that there is a possibility of losing. In such a case, it is necessary to immediately determine whether reopen treatment is to be performed or if reopen treatment is abandoned to adopt a palliative treatment. For this reason, an outcome forecast map that is intuitively understandable is useful.

  The map generated by the outcome forecast map generation unit 34 may be displayed as a three-dimensional image. For this purpose, it is necessary to assign a color or transparency to each pixel. For example, by making a part of a three-dimensional brain image transparent and making the area other than a desired area (for example, an area having a grace time of less than one hour at the current time) transparent, the area in the three-dimensional space It can also be displayed as a two-dimensional curved image. Such a display enables the whole brain to be observed in a comprehensive manner, which is useful in the treatment of cerebral infarction which requires prompt judgment.

  As described above, the medical image display apparatus 100 according to the present embodiment can support the determination of the treatment policy according to the grace time displayed on the outcome forecast map and the progress of the treatment.

Second Embodiment
Hereinafter, a second embodiment for generating a contradiction map from the difference between the regional cerebral tissue blood flow (rCBF) and the regional cerebral blood flow (rCVP) will be described.

(1) Configuration FIG. 7 is a functional block diagram showing an example of a functional configuration of the medical image processing apparatus 100 according to the second embodiment. As shown in FIG. 7, the medical image processing apparatus 100 includes a data input unit 21, a cerebral infarction index calculation unit 32, a difference calculation unit 38, a contradiction map generation unit 39, a color assignment unit 35, and a display unit 40.

  The functions of the cerebral infarction index calculation unit 32, the difference calculation unit 38, the contradiction map generation unit 39, and the color assignment unit 35 in the above configuration are realized by the main control unit 30 executing a program stored in the storage unit 20. Function.

  The same components as those in the first embodiment described with reference to FIG.

  In addition to the regional cerebral tissue blood flow (rCBF) described in the first embodiment, the data input unit 21 is a regional cerebral blood flow (rCVP: regional Cerebral blood flow) which is a regional blood flow in a subject's cerebral blood vessels. A distribution image of Vascular Perfusion and a distribution image of regional cerebrovascular blood volume (rCBV), which is a regional blood volume in a subject's cerebral blood vessels, are input.

  The difference calculating unit 38 calculates the difference between the regional cerebral tissue blood flow (rCBF) and the regional cerebral blood flow (rCVP). In calculating the difference, the difference calculating unit 38 aligns the local cerebral tissue blood flow distribution image with the local cerebral blood flow distribution image, and calculates the difference between rCBF and rCVP of the corresponding pixel or region. The difference may be a value obtained by subtracting rCVP from rCBF, or may be represented by the ratio of rCBF to rCVP. Further, the difference calculating unit 38 may calculate a difference that reflects the influence of the regional cerebral blood volume (rCBV).

  Regional cerebral blood volume (rCBV) is measured based on the amount of contrast agent that can not pass through the BBB, which passes through capillaries contained in brain tissue. The regional cerebral blood volume (rCBV) indicates the amount of blood per 100 ml of brain tissue (unit: ml / 100 ml).

  The regional cerebral blood flow (rCVP) is measured by measuring the process in which a contrast agent which can not pass through the blood brain barrier (BBB: Blood Brain Barrier) passes through capillaries contained in brain tissue. The unit of regional cerebral blood flow (rCVP) is the same as rCBF, and indicates the amount of blood flowing in capillaries per 100 ml of brain tissue per minute (unit: ml / min / 100 ml). Events are different. rCVP calculates local blood flow using the principle that a contrast agent can not pass through the BBB in normal brain capillaries and is distributed only in capillaries. Furthermore, rCVP also postulates the principle that normal brain tissue receives blood supply only from a single arterial system. However, in the pathogenesis of cerebral ischemia, these assumptions may not be satisfied in practice. For example, in ischemic brain tissue, contraction or swelling of the endothelial cells of capillaries breaks up the BBB, and contrast agent that normally distributes only in capillaries leaks out of capillaries. May be stored. In addition, blood flow may be supplied to the ischemic brain tissue from other routes (collateral circulation) other than the original feeding artery. When these events occur, rCVP will no longer represent the correct blood flow. On the other hand, since rCBF obtained by the XeCT / CBF test is not based on the above assumption, it represents the correct blood flow. Therefore, contradiction arises with rCBP when the above events occur.

  As described above, a medical image observing the behavior of the contrast agent transferred into the brain tissue and a medical image observing the behavior of the contrast agent not migrating to the brain tissue (that is, in the capillaries) according to the difference in the properties of the contrast agent. And observe different events. Thus, rCBF and rCVP are measurement results of another event. For example, since rCBF measures the contrast agent diffused to brain tissue, it is possible to observe the behavior of the contrast agent in the local brain tissue without being influenced by the presence of BBB or collateral circulation. Almost agrees with the behavior of oxygen carried in the bloodstream. On the other hand, rCVP is affected by the presence of BBB and collateral circulation because it measures contrast medium in blood vessels. Therefore, these values may be contradictory due to the different objects being measured.

  Such contradictions include various information about the site where the contradiction is observed. For example, if rCBF is greater than rCVP, that is, there is a high blood flow in brain tissue but a low blood flow in a blood vessel in brain tissue, collateral circulation effectively functions and blood from other than the original blood vessel The flow may be maintained. In addition, if there is a finding such as “Waking up asleep is awful, but it improves when awakening” as the patient's symptoms, by maintaining the blood flow in the collateral circulation by raising the blood pressure together with the above information. Treatment can be taken to prevent the spread of the infarct.

  Also, if rCBF is significantly larger than rCVP and rCBV is large, that is, there is a large blood flow in brain tissue, but if there is a small blood flow in a blood vessel in brain tissue, the BBB can not pass normally. The contrast agent may have leaked into brain tissue due to BBB rupture. This indicates that brain capillaries have lost the ability of BBB, which is their original function, which implies that recovery is difficult.

  The contradiction may be identified using the difference calculating unit 38 and the cerebral infarction index described in the first embodiment. For example, the cerebral infarction index calculated from rCBF described in the first embodiment and the cerebral infarction index calculated from rCVP by the same method (ie, cerebral infarction calculated using the value of rCVP instead of the value of rCBF) Indexes may be compared. Alternatively, the difference may be calculated by adding the value of rCBV to the difference. When each value is calculated, the cerebral infarction index calculated from rCBF may be a positive value, and the cerebral infarction index calculated from rCVP may be a negative value. This contradiction may be expressed by arranging images such as an outcome forecast map generated based on each cerebral infarction index, or may be expressed by one image by calculating a difference by the difference calculation unit 38. .

  The contradiction map generation unit 39 generates a contradiction map based on the calculated difference. Based on the difference generated from the contradiction between rCBF and rCVP calculated by the difference calculating unit 38, a contradiction map is generated in which the portion where the difference is observed is mapped. Details of the contradiction map will be described later.

(2) Operation Hereinafter, the operation of generating the contradiction map according to the second embodiment will be described.

  FIG. 8 is a flowchart showing an example of the operation of the medical image processing apparatus 100 according to the second embodiment.

  In ST201, the local brain tissue blood flow (rCBF) distribution image of the subject is input to the data input unit 21.

  In ST 203, the local cerebral blood flow (rCVP) distribution image of the subject is input to the data input unit 21.

  In ST205, the regional cerebral blood volume (rCBV) distribution image is input to the data input unit 21.

  In ST207, the difference calculating unit 38 calculates the difference between the regional cerebral tissue blood flow (rCBF) and the regional cerebral blood flow (rCVP).

The difference calculating unit 38 may calculate a value obtained by subtracting rCVP from rCBF as a difference, or may calculate a ratio of rCBF to rCVP as a difference. Alternatively, the difference between rCBF and rCVP multiplied by rCBV may be calculated as the difference. Furthermore, it may be calculated difference d typical values of rCBV as rCBV ₀ from the following equation (4).
For example, the difference d is
It may be calculated by

  In ST 209, the contradiction map generation unit 39 generates a contradiction map based on the difference.

  In ST211, the display unit 40 displays the contradiction map.

  FIG. 9 is a view for explaining a display example of the contradiction map of the medical image processing apparatus 100 according to the second embodiment. The contradiction map in FIG. 9 is an image showing the difference between the local cerebral blood flow distribution image and the local cerebral blood flow distribution image.

  An example of the contradiction map IMG3 is shown in the window W3 of FIG. A legend T4 in FIG. 9 indicates the case where the difference (d) calculated by the difference calculation unit 38 is positive, that is, the case where rCBF is larger than rCVP. The legend T4 shows two sections with the predetermined value (α) as the boundary value for the difference (d). The grid hatching in the upper part of the legend T4 indicates a region where the difference is larger than the predetermined value (α), and the hatching in the lower part of the legend T4 is a positive difference and is smaller than the predetermined value (α) An area is shown. It is possible to obtain more detailed information by dividing into such divisions.

  The legend T5 in FIG. 9 shows the case where the difference (d) is negative, that is, the case where rCBF is smaller than rCVP. In the legend T5, two divisions with the predetermined value (β) as the boundary value for the difference (d) are shown. The shaded area in the upper part of the legend T5 indicates a region where the difference is negative and is larger than a predetermined value (β), and the shaded area in the lower part of the legend T5 indicates a region smaller than the predetermined value (β) ing. Similar to the legend T4, more detailed information can be presented in a list by sorting.

  In the example of the contradiction map IMG3, lattice hatching and hatching exemplified in the legend T4 are shown in the upper right area. This area indicates an area where the difference is positive, and indicates, for example, that collateral circulation may actually maintain the blood flow in the brain tissue. Further, in the lower left area of the contradiction map IMG3, diagonal lines and hatching exemplified in the legend T5 are shown. This region indicates a region where the difference is negative, and indicates, for example, that there is a possibility that sufficient oxygen can not be supplied to brain tissue due to, for example, vascular malformation (AVM).

  The generated contradiction map may be displayed on the color scale by the color assignment unit 35 as in the first embodiment, or may be three-dimensionally generated. In this case, since the rCBF-based cerebral infarction index and the rCVP-based cerebral infarction index change from moment to moment, the contradiction map must also be updated in real time.

  Thus, more detailed information can be obtained from the information indicated by the contradiction map as to the condition of the observed region of the contradiction. In addition, based on more detailed information in the brain tissue obtained from the contradiction map, it is possible to support the determination of the treatment policy, the diagnosis of the patient leading to the improvement of the quality of life (QOL) and the grasp of the pathological condition.

  While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

DESCRIPTION OF SYMBOLS 10 Communication control apparatus 20 Memory | storage part 30 Main control part 40 Display part 50 Input part 21 Data input part 32 Cerebral infarction index calculation part 33 Outcome forecasting part 34 Outcome forecast map production part 35 Color allocation part 38 Difference calculation part 39 Contradiction map production part 100 medical image processing apparatus 200 medical image unified management server 300 modality apparatus

Claims (12)

A data input unit to which a local cerebral tissue blood flow rate, which is a local blood flow rate in the brain tissue of the subject calculated based on a medical image obtained by imaging the brain of the subject, is input;
Before Symbol local brain tissue blood flow, on the basis from the subject will develop cerebral infarction elapsed time and the time up to the present, the recovery may involve the time course of the subject's brain tissue A cerebral infarction index calculation unit which calculates a quantified cerebral infarction index;
A medical image processing apparatus comprising: The system further comprises an outcome prediction unit that predicts the outcome of the subject's brain tissue based on whether or not the cerebral infarction index calculated at the current time exceeds a predetermined threshold.
The medical image processing apparatus according to claim 1, characterized in that. The outcome prediction unit predicts a time when the cerebral infarction index exceeds a predetermined threshold, and predicts a grace period from the current time to the predicted time in real time.
The medical image processing apparatus according to claim 2 , characterized in that: An outcome forecast map generation unit that generates in real time an outcome forecast map in which the value of the cerebral infarction index is a pixel value;
A display unit for displaying the outcome forecast map in real time;
Further equipped with
The medical image processing apparatus according to any one of claims 1 to 3 , characterized in that: The image processing apparatus further comprises a color assignment unit that assigns at least one color information of lightness, saturation, hue and transparency to pixels based on the value of the cerebral infarction index.
The outcome prediction map generation unit generates a color map in which color information provided by the color assignment unit is associated with each pixel of the medical image.
The medical image processing apparatus according to claim 4 , characterized in that: The color assignment unit assigns at least one color information of lightness, saturation, hue, and transparency to pixels of the medical image based on the grace time.
The medical image processing apparatus according to claim 5 , characterized in that: When the medical image is a three-dimensional image, the color assignment unit three-dimensionally assigns color information.
The medical image processing apparatus according to claim 5 or 6 , wherein A local brain tissue blood flow, which is a local blood flow in the brain tissue of the subject, and a local cerebral blood flow, which is a local blood flow in the cerebral blood vessels of the subject ,
Based on the regional cerebral tissue blood flow and the elapsed time from the onset of the cerebral infarction in the subject to the present, the recovery possibility with time course of the brain tissue of the subject is numerically indicated A cerebral infarction index calculation unit which calculates a generalized cerebral infarction index;
An outcome forecast map generation unit that generates an outcome forecast map using the value of the cerebral infarction index as a pixel value;
A difference calculating unit that calculates a difference between the regional cerebral tissue blood flow and the regional cerebral blood flow;
And contradiction map generation unit that generates a contradiction map based on the previous Symbol differences,
A medical image processing apparatus comprising: Before yesterday infarction index calculation unit calculates a stroke index based on the local cerebrovascular blood flow in real time,
The difference calculating unit calculates a difference between a cerebral infarction index based on the local cerebral tissue blood flow and a cerebral infarction index based on the local cerebral blood flow.
The medical image processing apparatus according to claim 8 , characterized in that: A local cerebral blood volume, which is a local blood volume in the subject's cerebral blood vessels, is further input to the data input unit,
The difference calculation unit calculates the difference that reflects the effects of the regional cerebral vascular blood volume to said difference,
The medical image processing apparatus according to claim 8 or 9 , characterized in that A color assignment unit that assigns at least one color information of lightness, saturation, hue, and transparency based on the difference;
A display unit,
And further
The contradiction map generation unit generates a color map in which color information provided by the color allocation unit is associated with each pixel of the medical image,
The medical image processing apparatus according to any one of claims 8 to 10 , wherein the display unit displays the color map. A data input unit to which a local cerebral tissue blood flow rate, which is a local blood flow rate in the brain tissue of the subject calculated based on a medical image obtained by imaging the brain of the subject, is input;
Before SL based on the local brain tissue blood flow, and the stroke index calculation unit for calculating a stroke index quantifies recoverability over time of the subject's brain tissue,
An outcome prediction unit that predicts an outcome of brain tissue of the subject based on whether the cerebral infarction index calculated at the current time exceeds a predetermined threshold value,
The outcome prediction unit predicts a time when the cerebral infarction index exceeds a predetermined threshold, and predicts a grace period from the current time to the predicted time in real time.
Medical image processing apparatus characterized in that.