JP2015144725A - Medical image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device capable of depicting a thrombus sticking to an aneurysm with no radiation exposure.SOLUTION: A medical image processing device includes a magnetic resonance image acquisition part, an area specification part, and a thrombus detection part. The magnetic resonance image acquisition part acquires first magnetic resonance image data in which a blood vessel including an aneurysm of a subject is depicted, and second magnetic resonance image data in which a plurality of thrombi of the subject are depicted. The area specification part obtains a peripheral area of the aneurysm on the basis of the first magnetic resonance image data. The thrombus detection part detects a thrombus existing in the peripheral area from the second magnetic resonance image data.

Description

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

  To prevent stroke, it is important to detect cerebral aneurysms and predict the likelihood of rupture. The likelihood of an aneurysm rupture depends on the presence or absence of a thrombus within the aneurysm. Therefore, conventionally, imaging of thrombus using an X-ray CT (computed tomography) apparatus and evaluation of the drawn thrombus have been performed.

JP 2004-057340 A

  However, when imaging is performed by an X-ray CT apparatus, exposure of the subject becomes a problem.

  Therefore, an object of the present invention is to be able to depict a thrombus attached to an aneurysm without being exposed to radiation.

  A medical image processing apparatus according to an embodiment of the present invention includes a magnetic resonance image acquisition unit, a region specifying unit, and a thrombus detection unit. The magnetic resonance image acquisition unit acquires first magnetic resonance image data in which a blood vessel including an aneurysm of the subject is depicted and second magnetic resonance image data in which a plurality of thrombus of the subject is depicted. The region specifying unit obtains a peripheral region of the aneurysm based on the first magnetic resonance image data. The thrombus detection unit detects a thrombus present in the peripheral region from the second magnetic resonance image data.

1 is a functional block diagram of a medical image processing apparatus according to an embodiment of the present invention. The schematic diagram which represented the intermediate data produced | generated by the image processing in the medical image processing apparatus shown in FIG. 1 visually. 2 is a flowchart showing a flow of processing in the medical image processing apparatus shown in FIG. 1.

  A medical image processing apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a functional block diagram of a medical image processing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram visually representing intermediate data generated by image processing in the medical image processing apparatus shown in FIG. is there.

  The medical image processing apparatus 1 can be constructed by reading a medical image processing program into a large-scale computer such as a workstation provided with the input device 2 and the display device 3. However, a circuit may be used to configure the medical image processing apparatus 1. The medical image processing apparatus 1 is connected to a magnetic resonance imaging (MRI) apparatus 5 via a network 4.

  The MRI apparatus 5 magnetically excites a nuclear spin of a subject placed in a static magnetic field with a radio frequency (RF) signal having a Larmor frequency, and generates magnetic resonance (MR) generated by the excitation. ) An image diagnostic apparatus for reconstructing an image from a signal.

  The medical image processing apparatus 1 has a function of generating and displaying image data in which a thrombus attached to an aneurysm of a subject is extracted based on two types of MR image data collected by the MRI apparatus 5. For this purpose, the medical image processing apparatus 1 includes an MR image acquisition unit 1A, a region specifying unit 1B, a thrombus detection unit 1C, and a thrombus image generation unit 1D.

  The MR image acquisition unit 1 </ b> A has a function of acquiring the MR image data of the subject collected by the MRI apparatus 5 via the network 4. The MR image data may be acquired from a storage device such as a medical image server without being acquired directly from the MRI apparatus 5. In particular, the MR image acquisition unit 1A includes first MR image data in which a blood vessel including an aneurysm of the subject as shown in FIG. 2 (A) is depicted, and the subject as shown in FIG. 2 (B). Second MR image data in which a plurality of blood clots are depicted is acquired.

  The collection of MR image data depicting blood vessels is called magnetic resonance angiography (MRA). MRA includes a contrast-enhanced MRA that involves administration of a contrast agent to a subject and a non-contrast MRA that does not involve administration of a contrast agent to a subject. As non-contrast MRA, FBI (Fresh Blood Imaging) method and TOF (time of flight) method are known.

  When blood flow image data of a subject is collected by non-contrast MRA, non-contrast MR image data is acquired as first MR image data in which a blood vessel including an aneurysm is depicted. On the other hand, when blood flow image data of a subject is collected by contrast MRA, contrast MR image data is acquired as first MR image data. Hereinafter, a case where angiographic image data is acquired as the first MR image data will be described as an example.

  MR image data that can depict blood clots includes T2 * weighted image data, susceptibility weighted image (SWI) data, or MR image data captured by flare (FLAIR: fluid attenuated inversion recovery) method. Is representative. Therefore, the MR image acquisition unit 1A can be configured to acquire T2 * weighted image data, SWI data, or MR image data (FLAIR image data) captured by the FLAIR method as the second MR image data.

  The region specifying unit 1B has a function of obtaining a peripheral region of the aneurysm based on the first MR image data acquired by the MR image acquisition unit 1A. The peripheral region of the aneurysm can be specified by an arbitrary process. For example, an aneurysm detection, an aneurysm contour detection, an area expansion within the aneurysm outline, and a subtraction process of the area within the aneurysm outline before expansion from the expanded area it can.

  In that case, an aneurysm can first be detected from the first MR image data by image recognition processing such as pattern matching. When detecting an aneurysm by pattern matching, a spherical or circular template simulating an aneurysm was stretched and translated within the search range of the aneurysm in the first MR image data, and the matching rate exceeded the threshold In some cases, it can be recognized that an aneurysm is present. Note that pattern matching using a template is also called template matching.

  When an aneurysm is detected, the contour of the aneurysm can be detected by region expansion processing such as region growing. That is, the segmentation of the area occupied by the aneurysm can be performed. Region growing is a region expansion process in which a region including a seed is grown by adding a region spatially connected to a specified seed. Therefore, the center of gravity of the pattern used for pattern matching can be designated as seed.

  When the contour of the aneurysm is detected, a region A surrounded by the aneurysm boundary can be specified as shown in FIG. Then, the peripheral area of the aneurysm can be obtained based on the contour of the aneurysm. Specifically, the region A in the contour of the aneurysm is enlarged by a known dilation operation as a general digital image data morphology image processing, as shown in FIG. An enlarged region B along the contour of such an aneurysm can be obtained. Thereafter, by subtracting the area A in the contour of the aneurysm from the enlarged area B, the peripheral area C as shown in FIG.

  As another example, an area A in the contour of the aneurysm or a spherical area centered on the center of gravity of the pattern used for pattern matching may be used as the enlarged area B. In this case, a spherical region having a radius n (> 1) times the maximum value of the distance from the center of gravity to the boundary surface of the region A can be set as the enlarged region B. Conversely, the region A in the contour of the aneurysm may be extracted by threshold processing in a spherical region centered on the center of gravity of the pattern.

  The thrombus detection unit 1C has a function of detecting the thrombus D existing in the peripheral region C of the aneurysm specified by the region specifying unit 1B from the second MR image data as shown in FIG. 2 (E). Specifically, the thrombus D existing in the peripheral region C can be detected by the thrombus detection process for the second MR image data limited to the peripheral region C of the aneurysm. Alternatively, a plurality of thrombi may be detected by the thrombus detection process for the second MR image data, and the thrombus D existing in the peripheral region C of the aneurysm may be identified from the detected plurality of thrombi.

  For the thrombus detection process, a known process such as a binarization process or an edge detection process can be used as necessary in addition to the threshold process for the pixel value.

  As shown in FIG. 2 (F), the thrombus image generation unit 1D generates a function for generating, for display, image data in which the aneurysm and the thrombus D existing in the peripheral region C of the aneurysm are identifiable. The display device 3 has a function of displaying image data.

  Next, the operation and action of the medical image processing apparatus 1 will be described.

  FIG. 3 is a flowchart showing the flow of processing in the medical image processing apparatus 1 shown in FIG.

  First, first MR image data such as angiographic image data in which a blood vessel including an aneurysm of a subject as shown in FIG. 2 (A) is depicted in advance in the MRI apparatus 5, and as shown in FIG. 2 (B). Second MR image data such as T2 * weighted image data in which a plurality of blood clots of a subject is depicted is collected. That is, the first imaging for collecting tomographic image data in which blood vessels are emphasized in the MRI apparatus 5 and the second imaging for collecting tomographic image data capable of detecting a thrombus are executed.

  Next, in step S1, the MR image acquisition unit 1A uses the blood vessel image data in which the blood vessel including the aneurysm of the subject as shown in FIG. 2A is depicted as the first MR image data from the MRI apparatus 5. It is acquired directly via the network 4 or indirectly via a medical image server or the like.

  Next, in step S2, the region specifying unit 1B extracts the region A occupied by the aneurysm based on the first MR image data acquired by the MR image acquisition unit 1A. As a specific example, an aneurysm is detected by pattern matching on the first MR image data, and a region A occupied by the aneurysm is segmented by region growing. As a result, a region A in the contour of the aneurysm as shown in FIG.

  Next, in step S3, the region specifying unit 1B expands the region A within the contour of the aneurysm by Dilation processing or the like. As a result, an enlarged region B is created along the contour of the aneurysm as shown in FIG.

  Next, in step S4, the region specifying unit 1B calculates the peripheral region C of the aneurysm by subtracting the region A in the contour of the aneurysm from the enlarged region B. As a result, the peripheral region C of the aneurysm as shown in FIG.

  On the other hand, in step S5, the MR image acquisition unit 1A receives the second MR image data on which a plurality of blood clots of the subject as shown in FIG. It is acquired indirectly via a medical image server or the like.

  Next, in step S6, the thrombus detection unit 1C detects the thrombus D present in the peripheral region C of the aneurysm specified by the region specifying unit 1B from the second MR image data. As a specific example, the thrombus D attached to the aneurysm is extracted by the threshold processing of the second MR image data limited to the peripheral region C of the aneurysm as shown in FIG.

  When the threshold processing of the second MR image data is performed without being limited to the peripheral region C of the aneurysm, a large number of thrombus is detected. For this reason, the thrombus D existing in the peripheral region C of the aneurysm may be specified after detecting a large number of thrombus by the threshold processing.

  Next, in step S7, the thrombus image generation unit 1D generates, for display, image data in which the aneurysm and the thrombus D existing in the peripheral region C of the aneurysm are depicted in an identifiable manner. For example, image data in which the region A and the thrombus D in the contour of the aneurysm are identified and displayed in different colors on the blood vessel image data collected by MRA can be generated.

  The generated image data is output to the display device 3. As a result, the display device 3 displays a diagnostic image in which the aneurysm and the thrombus region attached to the aneurysm are emphasized so that they can be identified. For this reason, the user can easily observe the aneurysm and the thrombus attached to the aneurysm.

  That is, the medical image processing apparatus 1 as described above can generate and display image data in which a blood clot attached to the aneurysm is depicted together with the aneurysm using the two types of MR image data collected by the MRI apparatus 5 as original data. It is a thing.

  Therefore, according to the medical image processing apparatus 1, it is possible to depict a thrombus attached to the aneurysm without exposing the subject. In particular, it is effective for depicting a thrombus attached to a cerebral aneurysm.

  Although specific embodiments have been described above, the described embodiments are merely examples, and do not limit the scope of the invention. The novel methods and apparatus described herein can be implemented in a variety of other ways. Various omissions, substitutions, and changes can be made in the method and apparatus described herein without departing from the spirit of the invention. The appended claims and their equivalents include such various forms and modifications as are encompassed by the scope and spirit of the invention.

  For example, the medical image processing apparatus 1 may be built in the MRI apparatus 5 and the medical image processing apparatus 1 may be a component of the MRI apparatus 5.

DESCRIPTION OF SYMBOLS 1 Medical image processing apparatus 1A MR image acquisition part 1B Area | region specific part 1C Thrombus detection part 1D Thrombus image generation part 2 Input device 3 Display apparatus 4 Network 5 MRI apparatus

Claims (7)

A magnetic resonance image acquisition unit for acquiring first magnetic resonance image data in which a blood vessel including an aneurysm of the subject is depicted, and second magnetic resonance image data in which a plurality of thrombi of the subject is depicted;
A region specifying unit for obtaining a peripheral region of the aneurysm based on the first magnetic resonance image data;
A thrombus detection unit for detecting a thrombus present in the peripheral region from the second magnetic resonance image data;
A medical image processing apparatus.   2. The region specifying unit is configured to detect the aneurysm by pattern matching and detect the contour of the aneurysm by region growing, and obtain the peripheral region based on the contour of the aneurysm. Medical image processing apparatus.   The area specifying unit is configured to obtain the peripheral area by subtracting the area in the contour of the aneurysm after enlarging the area in the contour of the aneurysm by expansion calculation processing. Medical image processing apparatus.   The thrombus detection unit is configured to detect a thrombus present in the peripheral region by a thrombus detection process on the second magnetic resonance image data limited to the peripheral region. The medical image processing apparatus according to Item.   The thrombus detection unit is configured to detect the plurality of thrombus by a thrombus detection process for the second magnetic resonance image data, and to identify a thrombus existing in the peripheral region from the detected plurality of thrombus. The medical image processing apparatus according to any one of claims 1 to 3.   The magnetic resonance image acquisition unit is configured to acquire T2 * weighted image data, magnetic susceptibility weighted image data, or magnetic resonance image data imaged by a flare method as the second magnetic resonance image data. 6. The medical image processing apparatus according to any one of items 1 to 5.   The medical image processing apparatus according to any one of claims 1 to 6, further comprising a thrombus image generation unit that generates image data in which the thrombus and the aneurysm existing in the peripheral region are depicted so as to be distinguishable.

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