JP6556460B2 - Medical image processing apparatus and medical image processing method - Google Patents

Description

  Embodiments described herein relate generally to a medical image processing apparatus and a medical image processing method for processing a medical image.

  Recently, a specimen placement, a medical imaging device that captures a morphological image showing the anatomical form of Positron Emission Tom, which is one of the nuclear medicine diagnostic devices, and accumulation of radionuclides administered to the subject. A medical image diagnostic apparatus combined with a nuclear medicine diagnostic apparatus that captures a functional image showing a distribution is widely used, for example, an X-ray CT apparatus that is one of the medical image diagnostic apparatuses described above. A PET / CT apparatus combined with a PET (Positron Emission Tomography) apparatus, which is one of the nuclear medicine diagnosis apparatuses, has been widely used.

  The PET / CT apparatus generates a fusion image obtained by fusing a CT image and a PET image. The fusion image is an image that maximizes the display characteristics of the CT image and the PET image while reducing the burden on the observer. For example, in a PET image, it is useful for improving accuracy for diagnosing a tumor by determining whether a tumor is detected at an early stage together with a CT image. A conventional PET / CT apparatus, for example, interpolates the size of the fusion image according to the screen size, and adjusts it to a high-intensity region (for example, a region where a physiologically administered drug is easily accumulated) in the fusion image. The brightness of the screen is lowered and the fusion image is displayed.

  The conventional PET / CT apparatus adjusts the brightness of the screen including the high brightness area in the fusion image. For this reason, for example, the visibility of a region having a lower luminance than the high-luminance region (for example, a region where a drug is easily accumulated due to the presence of a lesion site or a lesion candidate site) is reduced. As a result, there is a possibility that the examination of the lesion candidate is omitted.

  An object of the present embodiment is to provide a medical image processing apparatus and a medical image processing method that can reduce the possibility of an examination omission of a lesion candidate.

According to the embodiment, the medical image processing apparatus has a function image indicating a spatial accumulation distribution of the radiation source administered to the subject, and the degree of accumulation of the radiation source in the subject exceeds a predetermined reference value. An area extraction unit for extracting an accumulation area; and a cutout image in which the high accumulation area is cut out from the functional image is generated . An image generation unit that generates a fusion image that is superimposed so as to display the morphological image .

1 is a block diagram illustrating an example of a medical image diagnostic apparatus including a medical image processing apparatus according to an embodiment. 6 is a flowchart showing a flow of processing in the medical image processing apparatus according to the embodiment. The figure which shows an example of the PET image reconfigure | reconstructed by the 2nd reconstruction part shown in FIG. 1, the cutout image produced | generated by the cutout image generation part, and the cutout image produced | generated by the cutout image generation part. The figure which shows the area | region database memorize | stored in the memory | storage part shown in FIG. The figure which shows the fusion image produced | generated in the fusion image generation part shown in FIG. The figure which shows an example of the display form of a 1st, 2nd and 3rd fusion image. The figure which shows an example of the display form of CT image, PET image, 3rd fusion image, and MIP image.

  Hereinafter, a medical image processing apparatus 200 according to the present embodiment will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 is a block diagram illustrating an example of a medical image diagnostic apparatus 300 including a medical image processing apparatus 200 according to the embodiment. In the present embodiment, a configuration of a PET-CT (Positron Emission Computed Tomography-Computed Tomography) apparatus is shown as an example of the medical image diagnostic apparatus 300.

  As shown in FIG. 1, the medical image diagnostic apparatus 300 includes a medical image imaging apparatus 100 and a medical image processing apparatus 200.

  A medical imaging apparatus 100 includes a slip ring 10, a high voltage generator 11, an X-ray tube 12, an X-ray detector 13, a projection data acquisition unit (DAS) 14 inside a gantry 30. A non-contact data transmission unit 15, a first preprocessing unit 16, a first reconstruction unit 17, and a first scanning control unit 18 are provided. The medical imaging apparatus 100 includes a gamma ray collection unit 20, a second preprocessing unit 21, an energy discrimination unit 22, a coincidence counting circuit 23, a second reconstruction unit 24, and a second scanning control unit in the gantry 30. 25.

  The gantry 30 houses a rotation support mechanism (not shown). The rotation support mechanism includes a rotation ring 19, a ring support mechanism that supports the rotation ring 19 so as to be rotatable about the body axis (Z axis) of the subject, and a rotation drive unit that drives the rotation of the rotation ring 19. Have. A top plate T on which the subject P can be placed is inserted into the opening of the rotating ring 19 and the detector ring described later. The top plate T is supported by a bed (not shown) so as to be movable along the central axis of the rotating ring 19 and the detector ring. Here, it is assumed that the body axis of the subject P placed on the top T coincides with the central axes of the rotating ring 19 and the detector ring.

  Mounted on the rotating ring 19 are a high voltage generator 11, an X-ray tube 12, a DAS 14, a non-contact data transmitter 15, a cooling device and a gantry control device (not shown), and the like.

  The high voltage generation unit 11 uses the power supplied via the slip ring 10 and the tube voltage applied to the X-ray tube 12 and the X-ray tube 12 under the control of the first scanning control unit 18. Tube current.

  The X-ray tube 12 radiates X-rays from the focal point of the X-rays to the subject P placed on the top board T in response to the application of the tube voltage and the supply of the tube current from the high voltage generator 11. The X-ray tube 12 generates X-rays having an energy spectrum corresponding to the tube voltage applied by the high voltage generator 11. The radiation range of X-rays is indicated by a two-dot chain line shown in FIG.

  The X-ray detector 13 is attached to the rotating ring 19 at a position and an angle facing the X-ray tube 12 across the rotation axis. The X-ray detector 13 has a plurality of X-ray detection elements. Here, it is assumed that a single X-ray detection element constitutes a single channel. The plurality of channels are orthogonal to the rotation axis and centered on the focal point of the emitted X-ray, and the arc direction (channel direction) having a radius from this center to the center of the light receiving part of the X-ray detection element for one channel. ) And the Z direction. A DAS 14 is connected to the output side of the X-ray detector 13.

  The X-ray detector 13 may be composed of a plurality of modules in which a plurality of X-ray detection elements are arranged in a line. At this time, the modules are arranged one-dimensionally in a substantially arc direction along the channel direction. Further, the plurality of X-ray detection elements may be two-dimensionally arranged in two directions of the channel direction and the slice direction. That is, the two-dimensional arrangement is configured by arranging a plurality of channels arranged in a one-dimensional manner along the channel direction in a plurality of rows in the slice direction. The X-ray detector 13 having such a two-dimensional X-ray detection element array may be configured by arranging a plurality of the above-described modules arranged in a one-dimensional shape in a substantially arc direction in a plurality of rows in the slice direction.

  The DAS 14 includes an IV converter that converts a current signal of each channel of the X-ray detector 13 into a voltage, an integrator that periodically integrates the voltage signal in synchronization with an X-ray exposure period, and the integrator. An amplifier that amplifies the output signal and an analog-digital converter that converts the output signal of the amplifier into a digital signal are attached to each channel. The DAS 14 transmits the output data (pure raw data) to the first preprocessing unit 16 via the non-contact data transmission unit 15 using magnetic transmission / reception or optical transmission / reception. The first preprocessing unit 16 performs preprocessing on the pure raw data output from the DAS 14. The preprocessing includes, for example, sensitivity non-uniformity correction processing between channels, X-ray strong absorber, processing for correcting signal signal drop or signal loss due to extreme metal intensity mainly. The first pre-processing unit 16 obtains the view angle when data of the pre-reconstructed data immediately before the reconstruction process (raw data or projection data, here called projection data) is collected. Is transmitted to the first reconstruction unit 17 and the storage unit 48 in association with data representing

  The projection data is a set of data values corresponding to the intensity of X-rays that have passed through the subject. Here, for convenience of explanation, a set of projection data over all channels having the same view angle collected almost simultaneously in one shot is referred to as a projection data set. Further, the view angle represents each position of the circular orbit around which the X-ray tube 12 circulates around the rotation axis as an angle in a range of 360 ° with the uppermost portion of the circular orbit vertically upward from the rotation axis as 0 °. It is. The projection data for each channel in the projection data set is identified by the view angle, cone angle, and channel number.

  The first reconstruction unit 17 uses the Feldkamp method or the cone beam reconstruction method based on the projection data set transmitted from the first preprocessing unit 16 and having a view angle in the range of 360 ° or 180 ° + fan angle. Thus, the substantially cylindrical volume data is reconstructed. For example, the first reconstruction unit 17 uses, for example, a fan beam reconstruction method (also referred to as a fan beam convolution back projection method), a filtered back projection method (FBP), a successive approximation reconstruction method, or the like. A two-dimensional CT image (a tomographic image, hereinafter simply referred to as a CT image) is reconstructed from the projection data set. The Feldkamp method is a reconstruction method when the projection ray intersects the reconstruction surface like a cone beam, and it is treated as a fan projection beam when convolved on the assumption that the cone angle is small. Back projection is an approximate image reconstruction method that processes along a ray during scanning. The cone beam reconstruction method is a reconstruction method that corrects projection data in accordance with the angle of the ray with respect to the reconstruction surface, as a method that suppresses cone angle errors more than the Feldkamp method. The first reconstruction unit 17 transmits the reconstructed volume data and CT image to the storage unit 48.

  The first scan control unit 18 controls power supply from the slip ring 10 to the high voltage generation unit 11 so as to perform imaging according to a predetermined scan sequence.

  The gamma ray collection unit 20 has a detector ring (not shown) that is a gamma ray detection mechanism. Typically, a plurality of detector rings are arranged in the gantry 30 along the Z axis. The detector ring has a plurality of gamma ray detectors arranged circumferentially around the Z axis.

  The plurality of gamma ray detectors detect gamma rays emitted from a radiation source injected into the subject P, and generate detection signals corresponding to the energy of the gamma rays. Since the plurality of gamma ray detectors are arranged circumferentially around the body axis of the subject P, gamma rays can be detected in a plurality of directions (solid angles). Specifically, the gamma ray detector has a plurality of scintillators and a plurality of photoelectric conversion elements. The scintillator generates fluorescence when gamma rays are incident. The fluorescence is guided to the photoelectric conversion element through a light guide (not shown). The photoelectric conversion element receives fluorescence from the scintillator via the ride guide, amplifies the amount of received fluorescence, and generates a detection signal corresponding to the amount of light. The photoelectric conversion element outputs the generated detection signal to the second preprocessing unit 21 and the energy discriminating unit 22.

  Here, in PET, a pair of annihilation radiations, which are emitted in opposite directions at the same time as positrons and electrons emitted from one radiation source administered to a subject, are simultaneously emitted by a plurality of gamma ray detectors. To detect. A line connecting the incident positions of a pair of annihilation radiations is called LOR (Line of Response). PET discriminates this pair of annihilation radiation and generates a spatial distribution of radiation sources.

  The second preprocessing unit 21 calculates the energy value of gamma rays incident on the gamma ray detector based on the detection signal output from the gamma ray detector. The second preprocessing unit 21 measures the detection time of the gamma rays incident on the gamma ray detector based on the detection signal output from the gamma ray detector. Based on the pair of detection signals output from the gamma ray detector, the second preprocessing unit 21 determines the position information of the scintillator that has generated the fluorescence based on the ratio of the amount of fluorescence received by the photoelectric conversion element, that is, The incident position of a pair of gamma rays is calculated. The second preprocessing unit 21 outputs the gamma ray energy value information, detection time information, and incident position information to the energy discriminating unit 22.

  The energy discriminating unit 22 discriminates the detection signal output from the gamma ray detector based on the energy value information output from the second preprocessing unit 21. Specifically, the energy discriminating unit 22 discriminates a detection signal having an energy value within an energy window width of about ± 20 percent around the energy peak 511 keV of gamma rays. In addition, when an energy value is lower than an energy window lower limit (lower threshold, about 300 to 400 keV), it is regarded as a scattered radiation component of gamma rays. Moreover, when an energy value is higher than an energy window upper limit (upper limit threshold, about 600 to 850 keV), it is regarded as pile-up. Pile-up means that signals input simultaneously or at very short time intervals overlap each other.

  The coincidence counting circuit 23 counts a pair of detection signals discriminated by the energy discriminating unit 22 based on the detection time information output from the second pre-processing unit 21 based on simultaneity. Specifically, the energy discriminating unit 22 counts a pair of detection signals for each LOR whose detection time difference is within a time window width of 2 to 5 nsec from the gamma rays incident on the gamma ray detector. In the embodiment, a value obtained by counting the pair of detected detection signals for each LOR is defined as coincidence counting information. The coincidence count information includes a data set (event data) that associates an incident position and an incident time of each of a pair of gamma rays generated for each event that represents an event in which gamma rays are incident on the scintillator. Here, the coincidence circuit 23 obtains the number of coincidence counts for each of the plurality of medical images. That is, the coincidence counting circuit 23 obtains the count number of event data generated for each event. In the present embodiment, the count number of event data generated for each event is described as the event number. The coincidence counting circuit 23 repeatedly performs the counting process of the pair of detection signals thus discriminated to obtain coincidence counting information and event number information in a plurality of directions (solid angles). The coincidence counting circuit 23 outputs the coincidence counting information in the plurality of directions to the second reconstruction unit 24 and the storage unit 48. The coincidence counting information is stored in the storage unit 48 in association with the PET image reconstructed by the second reconstruction unit 24. Further, the coincidence counting circuit 23 outputs the event number information to the storage unit 48. The event number information is stored in the storage unit 48 in association with the PET image reconstructed by the second reconstruction unit 24.

  The second reconstruction unit 24 reconstructs a plurality of PET images using event data included in the coincidence counting information in a plurality of directions output from the coincidence counting circuit 23. A PET image is obtained by reconstructing a spatially integrated distribution of a radiation source from the above data obtained by using a drug labeled with a radioisotope (positron nuclide) as a radiation source. Specifically, the second reconstruction unit 24 executes a calculation process by applying a filtered back projection method (FBP), a successive approximation reconstruction method, or the like, and obtains a PET image from the coincidence information. Reconfigure. The data of the reconstructed plurality of PET images is stored in the storage unit 48 in association with the coincidence counting information in the plurality of directions.

  The second scan control unit 25 controls the gamma ray collection unit 20 so as to collect gamma rays according to a predetermined scan sequence. The scan sequence defines the collection timing of gamma rays.

  The medical image processing apparatus 200 includes an area extraction unit 40, an image generation unit 41, an interface (I / F) 45, an input unit 46, a display unit 47, a storage unit 48, and a system control unit 49. .

  The region extraction unit 40 extracts a highly integrated region where the integration degree of the radiation source exceeds a predetermined reference value from the PET image. The region extraction unit 40 extracts, as the highly integrated region, for example, a physiologically highly integrated region with a high integration level of the radiation source from the PET image due to physiological factors in the subject P. Further, the region extraction unit 40 extracts from the PET image a lesion candidate region having a high degree of accumulation of radiation sources due to the presence of a lesion site or a lesion candidate site in the subject P. The region extraction unit 40 transmits the extracted physiologically highly integrated region and lesion candidate region data to the image generation unit 41.

  Here, in the reconstruction process in the first reconstruction unit 17 or the second reconstruction unit 24 or the storage process of the CT image or the PET image in the storage unit 48, the position coordinate system in the CT image and the position coordinate in the PET image Associated with the system. Therefore, the region extraction unit 40 may extract the physiologically highly integrated region from the PET image based on the contour data of the region corresponding to the physiologically highly integrated region obtained from the CT image. The physiologically highly integrated region is, for example, the brain, heart, bladder, kidney, and the like.

  The image generation unit 41 includes a cutout image generation unit 42, a cutout image generation unit 43, and a fusion image generation unit 44.

  The cut-out image generation unit 42 generates a cut-out image obtained by cutting out the highly integrated region from the PET image based on the data of the physiologically highly integrated region and the lesion candidate region transmitted from the region extracting unit 40. The cutout image generation unit 42 transmits the generated cutout image to the fusion image generation unit 44 and the display unit 47.

  The cutout image generation unit 43 generates a cutout image obtained by cutting out the physiologically highly integrated region and the lesion candidate region from the PET image based on the data of the physiologically highly integrated region and the lesion candidate region transmitted from the region extracting unit 40. To do. The cutout image generation unit 43 transmits the generated cutout image to the fusion image generation unit 44 and the display unit 47. Note that the cutout image generation unit 42 may generate a cutout image in which only the physiologically highly integrated region or only the lesion candidate region is cut out from the PET image.

  The fusion image generating unit 44 generates a first fusion image obtained by superimposing the CT image and the PET image. Further, the fusion image generation unit 44 generates a second fusion image obtained by superimposing the CT image and the cutout image generated by the cutout image generation unit 43. Further, the fusion image generation unit 44 generates a third fusion image obtained by superimposing the CT image and the cutout image generated by the cutout image generation unit 42. The fusion image generation unit 44 transmits the first fusion image, the second fusion image, and the third fusion image to the display unit 47.

  In the image generation in the image generation unit 41, at the time of window conversion, for example, the window width and the window level may be adjusted according to at least one of the plurality of highly integrated regions in the cut-out image. Good. Thereby, when displaying the cut-out image, it is possible to set an optimum window individually for each of the plurality of highly integrated regions. That is, it is possible to observe a lesion site or a lesion candidate site with an optimal window without performing window conversion on all regions in the PET image.

  Further, the image generation unit 41 may generate a maximum intensity projection (MIP) image obtained by projecting the volume data by the maximum value projection method. Further, the image generating unit 41 may generate a MinIP (Minimum Intensity Projection) image obtained by projecting the volume data by the minimum value projection method. Further, the image generation unit 41 may generate a ray summation image obtained by projecting the volume data by the sum value projection method. Thereby, it is difficult to receive the noise component of the image, and an image with high contrast can be obtained.

  The interface 45 communicates with an external device by wire or wirelessly. External devices include, for example, modalities other than the PET-CT apparatus, radiation department information management system (RIS), hospital information system (HIS), and PACS (Picture Archiving and Communication System). Server or other workstation included.

  The input unit 46 is an interface for inputting commands and the like according to user operations. The input unit 46 includes, for example, a keyboard, a mouse, a touch panel, a trackball, various buttons, and the like.

  The display unit 47 displays the CT image, the PET image, the cutout image, the cutout image, the first fusion image, the second fusion image, the third fusion image, the MIP image, the MinIP image, the laysum image, and the like on a display device. For example, the display unit 47 adjusts the window width, the window level, the opacity, and the display color according to the clipped image, and displays the clipped image. That is, the window width, the window level, the opacity, and the display color are adjusted after excluding a portion with a high pixel value in the PET image. Thereby, the visibility of the area | region where brightness | luminance is smaller than the said highly integrated area | region in PET image improves. As a display device, a CRT display (Cathode Ray Tube Display), a liquid crystal display (LCD), an organic EL display (OELD: Organic Electro Luminescence Display), a plasma display, or the like can be used as appropriate.

  The display unit 47 may adjust the window width, the window level, the opacity, and the display color for each image display area.

  The storage unit 48 is an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like that can store a relatively large amount of data. The storage unit 48 stores data of a plurality of PET images reconstructed by the second reconstruction unit 24. In addition, the storage unit 48 stores the coincidence counting information output from the coincidence counting circuit 23 in a plurality of directions and the event number information in association with each other. The storage unit 48 associates the position coordinate system in the CT image transmitted from the first reconstruction unit 17 with the position coordinate system in the PET image transmitted from the second reconstruction unit 24, and Store the data. The storage unit 48 associates the position coordinate system in the CT image transmitted from the first reconstruction unit 17 with the position coordinate system in the PET image transmitted from the second reconstruction unit 24, and stores the PET image of the PET image. Data may be stored. The storage unit 48 stores the projection data transmitted from the first preprocessing unit 16 and the volume data reconstructed by the first reconstruction unit 17.

  The storage unit 48 appends region information associated with the highly integrated region (physiological highly integrated region and lesion candidate region) extracted by the region extracting unit 40 as supplementary information, and registers the data of the highly integrated region, respectively. . For example, the storage unit 48 uses the position coordinates of the highly integrated region in the PET image, the maximum pixel value in the highly integrated region, the maximum diameter of the highly integrated region, and the type of the region highly integrated region as supplementary information. Thus, the data of the highly integrated area extracted by the area extracting unit 40 is registered. That is, in the storage unit 48, a region database relating to the physiologically highly integrated region and the lesion candidate region is constructed. Thereby, for example, in the follow-up examination, it is possible to search the region database and refer to data of a highly integrated region obtained by follow-up observation before and after treatment.

  The storage unit 48 uses an optical disk such as a magneto-optical disk, a CD (Compact Disc), a DVD (Digital Versatile Disc), and a Blu-ray (Blu-ray (registered trademark)) in addition to a magnetic disk such as an HDD. May be. The storage area of the storage unit 48 may be in the medical image processing apparatus 200 or in an external storage device connected by the network.

  The system control unit 49 controls operations of the medical imaging device 100, the region extraction unit 40, the image generation unit 41, the interface 45, the input unit 46, the display unit 47, and the storage unit 48.

  Here, the flow of processing by the medical image processing apparatus 200 according to the embodiment will be described with a specific example.

  FIG. 2 is a flowchart showing a flow of processing in the medical image processing apparatus 200 according to the embodiment. 3 shows a PET image reconstructed by the second reconstruction unit 24 shown in FIG. 1, a cut-out image generated by the cut-out image generation unit 43, and a cut-out image generated by the cut-out image generation unit 42. It is a figure which shows an example. FIG. 4 is a diagram showing an area database stored in the storage unit 48 shown in FIG.

  As shown in FIG. 2, the region extraction unit 40 extracts physiologically highly integrated regions (eg, brain, heart, bladder, kidney, etc.) and lesion candidate regions from the PET image shown in FIG. (Step ST1). As a method for extracting the physiologically highly integrated region and the lesion candidate region, the following method may be mentioned.

  As the first extraction method, filter processing (removal / reduction of noise, adjustment of fluctuation range of integrated value, etc.) is executed. After filtering, an arbitrary point set by the user is set on the PET image (pointing). After setting an arbitrary point, an ROI (Region Of Interest) based on the arbitrary point is set. Further, segmentation (feature extraction, edge extraction, etc.) is performed. After segmentation, the extracted area is edited (enlargement / reduction / division / integration / deletion, etc.).

  As the second extraction method, filter processing (removal / reduction of noise, adjustment of the fluctuation range of integrated values, etc.) is executed. After the filtering process, a local maximum point indicating the position where the maximum pixel value of each highly integrated region in the PET image is detected is extracted. After extracting the local maximum point, an ROI based on the local maximum point is set. Further, segmentation (feature extraction, edge extraction, etc.) is performed. After segmentation, the extracted area is edited (enlargement / reduction / division / integration / deletion, etc.).

  By the extraction method, the region extraction unit 40 extracts a physiologically highly integrated region and a lesion candidate region in the PET image.

  After extracting the physiologically highly integrated region and the lesion candidate region from the PET image, the cutout image generating unit 43 generates a cutout image by cutting out the physiologically highly integrated region and the lesion candidate region from the PET image (step ST2). ). The cut-out image is shown in FIG. For each of the physiologically highly integrated region and the lesion candidate region cut out from the PET image, for example, the region number shown in FIG. 4, the position coordinates of the highly integrated region in the PET image, the maximum pixel value of the highly integrated region, the highly integrated region The maximum diameter of the area, the type of the highly integrated area, the name of the part (for example, brain cortex, heart, liver, bladder, kidney, etc.) are attached as incidental information.

  Here, in the reconstruction process or the storage process, the position coordinate system in the CT image and the position coordinate system in the PET image are associated with each other. Thereby, it is possible to distinguish a physiologically highly integrated region and a lesion candidate region on a PET image. For this reason, the name of the said site | part is attached to the physiologically highly integrated area | region as incidental information.

  Further, the cut-out image generation unit 42 generates a cut-out image obtained by cutting out the physiologically highly integrated region and the lesion candidate region from the PET image (step ST3). The cropped image is shown in FIG. It should be noted that a specific value (for example, 0) may be set for the pixel in the portion where the physiologically highly integrated region and the lesion candidate region are cut out.

  FIG. 5 is a diagram showing the first, second, and third fusion images generated by the fusion image generating unit 44 shown in FIG.

  The fusion image generation unit 44 generates a first fusion image obtained by superimposing the CT image and the PET image. The first fusion image is shown in FIG. In addition, the fusion image generation unit 44 generates a second fusion image obtained by superimposing the CT image and the cutout image generated by the cutout image generation unit 43. The second fusion image is shown in FIG. In addition, the fusion image generation unit 44 generates a third fusion image obtained by superimposing the CT image and the cutout image generated by the cutout image generation unit 42. The third fusion image is shown in FIG. 5C (step ST4).

  By the above process, a cutout image, a cutout image, a first fusion image, a second fusion image, and a third fusion image are obtained.

  In the fusion image generation in step ST4, for example, the window width and the window level may be adjusted in accordance with at least one of the plurality of highly integrated regions in the second fusion image. Thus, when displaying the second fusion, it is possible to set an optimum window individually for each of the plurality of highly integrated regions. That is, it is possible to observe a lesion site or a lesion candidate site with an optimal window without performing window conversion on all regions in the second fusion image.

  FIG. 6 is a diagram illustrating an example of a display form of the first, second, and third fusion images. FIG. 7 is a diagram illustrating an example of a display form of the CT image, the PET image, the third fusion image, and the MIP image.

  In FIG. 6, the display area of the display unit 47 is divided into nine. The display unit 47 displays the first fusion image of each of the axial, coronal, and sagittal sections in the first line. The display unit 47 displays the second fusion image of each of the axial section, the coronal section, and the sagittal section in the second row. The display unit 47 displays a third fusion image of each of the axial section, the coronal section, and the sagittal section in the third row.

  In FIG. 7, the display area of the display unit 47 is divided into four. The display unit 47 displays a CT image, a PET image, a third fusion image, and an MIP image. The display unit 47 may adjust and display the window width, window level, opacity, and display color for each image. For example, the display unit 47 adjusts the window width, the window level, the opacity, and the display color according to at least one of the plurality of highly integrated regions in the cut-out image and the second fusion image. May be. Thereby, when displaying the cutout image and the second fusion image, the display unit 47 can set an optimum window individually for each of the plurality of highly integrated regions in the cutout image and the second fusion image. become. That is, the display unit 47 can display a lesion site or a lesion candidate site in an optimal window without performing window conversion on all regions in the PET image and the second fusion image.

  The display shown in FIGS. 6 and 7 is an example, and the present invention is not limited to this. The display unit 47 appropriately displays the CT image, the PET image, the cutout image, the cutout image, the first fusion image, the second fusion image, the third fusion image, the MIP image, the MinIP image, the laysum image, and the like according to a user instruction. It may be displayed. The display unit 47 displays the CT image, the PET image, the cutout image, the cutout image, the first fusion image, the second fusion image, the third fusion image, the MIP image, the MinIP image, the Latham image, and the like two-dimensionally and three-dimensionally. You may display by at least any one of the dimensions. Further, the display unit 47 may change the window size for each image and display it. In addition, the display unit 47 displays a part of areas such as the CT image, PET image, clipped image, clipped image, first fusion image, second fusion image, third fusion image, MIP image, MinIP image, and latham image. The edited image may be displayed. For example, the display unit 47 may enlarge and display at least one of the highly integrated regions in the cut-out image.

  According to the above configuration, in the medical image processing apparatus 200 according to the present embodiment, the region extraction unit 40 uses the PET image indicating the spatial accumulation distribution of the radiation source administered to the subject P to determine the degree of radiation source integration. Highly integrated regions (for example, physiologically highly integrated regions and lesion candidate regions) that exceed a predetermined reference value are extracted. The cutout image generation unit 43 generates a cutout image obtained by cutting out the highly integrated region extracted by the region extraction unit 40 from the PET image. This makes it possible to improve the visibility of the highly integrated region without being affected by the screen brightness.

  Therefore, the medical image processing apparatus 200 can reduce the possibility that an examination omission of a lesion site or a lesion candidate site will occur.

  In addition, the medical image processing apparatus 200 can improve the visibility of a region having a lower luminance than the physiologically highly integrated region and the lesion candidate region by adjusting the luminance of the screen according to the clipped image.

  The medical image processing apparatus 200 also superimposes a CT image and a clipped image obtained by cutting out a physiologically highly integrated region and a lesion candidate region from a PET image in a fusion image. It is possible to adjust the screen brightness without considering the brightness of the lesion candidate area. That is, when displaying a fusion image, the medical image processing apparatus 200 can improve the visibility of a region having a lower luminance than the physiologically highly integrated region and the lesion candidate region.

  In the image generation in the image generation unit 41, at the time of window conversion, for example, the window width and the window level may be adjusted according to at least one of the plurality of highly integrated regions in the cut-out image. Good. Thereby, when displaying the cut-out image, it is possible to set an optimum window individually for each of the plurality of highly integrated regions. That is, it is possible to observe a lesion site or a lesion candidate site with an optimal window without performing window conversion on all regions in the PET image.

  Further, the medical image processing apparatus 200 stores in the storage unit 48 the position coordinates of the highly integrated region in the PET image, the maximum pixel value in the highly integrated region, the maximum diameter of the highly integrated region, and the region of the highly integrated region. The data of the highly integrated area extracted by the area extraction unit 40 is registered with the type as incidental information. That is, in the storage unit 48, a region database relating to the physiologically highly integrated region and the lesion candidate region is constructed. Thereby, for example, in the follow-up examination, it is possible to search the region database and refer to data of a highly integrated region obtained by follow-up observation before and after treatment.

  In the above embodiment, a PET / CT apparatus is shown as an example of a medical image diagnostic apparatus, but the present invention is not limited to this. The medical image processing apparatus 200 according to the embodiment can also be applied to a SPECT / CT apparatus that combines the X-ray CT apparatus and a SPECT (Single Photon Emission Computed Tomography) apparatus that is one of the nuclear medicine diagnosis apparatuses. . The medical image processing apparatus 200 according to the embodiment is also applied to a PET / MRI apparatus in which a magnetic resonance imaging diagnostic apparatus (MRI: Magnetic Resonance Imaging) which is one of the medical image imaging apparatuses is combined with the PET apparatus. Is possible.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 300 ... Medical image diagnostic apparatus, 100 ... Medical imaging device, 10 ... Slip ring, 11 ... High voltage generation part, 12 ... X-ray tube, 13 ... X-ray detector, 14 ... Data collection part (DAS), 15 ... Non-contact data transmission unit, 16 ... first preprocessing unit, 17 ... first reconstruction unit, 18 ... first scanning control unit, 19 ... rotating ring, 20 ... gamma ray collection unit, 21 ... second preprocessing unit, 22 ... energy discriminating unit, 23 ... coincidence counting circuit, 24 ... second reconstruction unit, 25 ... second scanning control unit, 30 ... gantry, P ... subject, T ... top plate, 200 ... medical image processing apparatus, 40 ... Area extractor 41... Image generator 42. Clipped image generator 43 43 Cutout image generator 44. Fusion image generator 45 45 Interface (I / F) 46 Input unit 47 Display unit 48 ... Storage unit, 49 ... System control .

Claims (8)

A region extraction unit for extracting a highly integrated region in which the degree of integration of the radiation source in the subject exceeds a predetermined reference value from a functional image indicating a spatially integrated distribution of the radiation source administered to the subject;
A clipping image is generated by clipping the highly integrated region from the functional image, and a morphological image indicating the anatomical form of the subject and the clipped image are superimposed so that the morphological image is displayed in the highly integrated region A medical image processing apparatus comprising: an image generation unit that generates a fusion image .   The medical image processing apparatus according to claim 1, wherein the region extraction unit extracts, as the highly integrated region, a physiologically highly integrated region having a high integration level of the radiation source due to physiological factors from the functional image.   The region extraction unit extracts the physiologically highly integrated region from the functional image based on contour data of a region corresponding to the physiologically highly integrated region obtained from a morphological image indicating the anatomical form of the subject. The medical image processing apparatus according to claim 2.   The region extraction unit extracts, as the highly integrated region, a lesion candidate region having a high degree of integration of the radiation source due to the presence of a lesion site or a lesion candidate site from the functional image. Medical image processing apparatus. Wherein the image generating unit, before Symbol mode image and the high integration region for generating a full Yujon image obtained by superimposing processes the clipped image cut out from the functional image according to claim 1 to 4 of the medical image according to any one of Processing equipment.   The medical image processing apparatus according to claim 1, further comprising a display unit configured to display the clipped image by adjusting a window width, a window level, an opacity, and a display color according to the clipped image.   The medical image processing apparatus according to claim 1, further comprising an area database that registers area data associated with the highly integrated area and registers data of the highly integrated area. From the functional image showing the spatial accumulation distribution of the radiation source administered to the subject, extract a highly integrated region where the degree of integration of the radiation source in the subject exceeds a predetermined reference value,
Generating a clipped image obtained by cutting out the highly integrated area from the functional image ;
A medical image processing method for generating a fusion image in which a morphological image indicating the anatomical form of the subject and the cutout image are superimposed so as to display the morphological image in the highly integrated region .