JP2006095032A - Medical image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical image processor capable of storing respective images while keeping a high resolution even though a matrix size is changed when superimposing a plurality of images. <P>SOLUTION: This medical image processor performing superimposing and storing of the plurality of images photographed by a medical image photographing device is equipped with a matrix size changing means changing the matrix size of another image according to one with a minimum matrix size when the matrix sizes of the plurality of images are different, a positioning image forming means superposing the plurality of images and making a positioning image by converting and processing the respective images such that mutual positional relationship coincides, a positioning information storing means storing the history of the converting and processing by the positioning image forming means as positioning information, and a storing means reconstructing and storing the positioning images from original data prior to changing the matrix size using the positioning information. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a medical image processing apparatus capable of superimposing and storing a plurality of images photographed by a medical image photographing apparatus.

  Medical imaging equipment such as X-ray CT (Computed Tomography), MRI (Magnetic Resonance Imaging), ultrasonic diagnostic equipment, PET (Positron Emission Tomography), etc. It provides morphological information or functional information in the examiner's body as an image, and plays an important role in the diagnosis and treatment of diseases. Images captured by each medical image capturing apparatus have different characteristics, and an imaging technique (modality) corresponding to the purpose of diagnosis is selected. Moreover, the mutual shortcoming is complemented by superimposing the image image | photographed with several modalities (patent document 1).

  For example, a PET device is a device that detects radiation emitted from a subject who has previously been administered a radiopharmaceutical and takes a biodistribution image of the drug, and uses a radiopharmaceutical that easily accumulates in cancer cells. By doing so, cancer lesions can be detected at an early stage. However, images obtained with PET can represent the size and shape of a lesion, but it is difficult to diagnose where it exists in human tissue. On the other hand, the X-ray CT apparatus exposes X-rays from around the subject and detects the transmitted X-rays, thereby imaging the body tissue of the subject and obtaining detailed morphological information. It can be difficult to detect if the lesion is small. Therefore, by superimposing the images obtained by both apparatuses, it is possible to accurately diagnose which tissue the lesion found by PET belongs to.

  However, in general, when a plurality of apparatuses are used for inspection, even if the subject is the same, the cross-sectional shape, the portion included in the image, and the like rarely match well. Therefore, when superimposing images, it is necessary to match the positional relationship between the two images by rotating, moving, compressing or expanding the images. FIG. 3 schematically shows this, and shows a state in which the image is converted so that the corresponding points a and a ′ coincide with the points b and b ′.

  At this time, if images of different matrix sizes are handled as they are, the software program configuration becomes complicated. Therefore, when images with different matrix sizes are overlapped, the other one is generally converted to one matrix size. Process. In this case, usually, considering the processing speed and the memory used, the matrix size of the other image is reduced in accordance with the image having the smaller matrix size.

JP 2002-214347 A

In actual diagnosis, there are not a few cases where it is desired to individually observe each image used for superposition after superposition of a plurality of images as described above. However, in the conventional medical image processing apparatus, the image after the matrix size conversion is stored when the image is stored after being overlaid. Therefore, when the image is converted to a smaller matrix size, the image is subsequently read and observed. Will use images with inferior resolution.
Therefore, the problem to be solved by the present invention is a medical image processing apparatus capable of storing each image while maintaining a high resolution even when the matrix size is changed when performing the overlay processing of a plurality of images. Is to provide.

A medical image processing apparatus according to the present invention made to solve the above problems is a medical image processing apparatus that superimposes and stores a plurality of images captured by a medical image capturing apparatus,
a) Matrix size changing means for changing the matrix size of other images in accordance with the smallest matrix size when the matrix sizes of the plurality of images are different;
b) a registration image creating unit that creates a registration image by superimposing the plurality of images and performing conversion processing so that each image has a mutual positional relationship;
c) alignment information storage means for storing a history of conversion processing by the alignment image creating means as alignment information;
d) storage means for reconstructing and storing a registration image from original data before changing the matrix size of the plurality of images using the registration information;
It is characterized by providing.

  In the medical image processing apparatus of the present invention, the storage unit may store the alignment information and original data before changing the matrix size of the plurality of images in association with each other.

  In the present invention, a plurality of images converted so that their positional relations coincide with each other are referred to as alignment images, and an image obtained by superimposing the alignment images is referred to as a superimposed image.

  In the present invention, when a plurality of images photographed by the medical image photographing device are superimposed, even if the alignment is performed after changing the matrix size, the original image is stored when the images are stored after the alignment. Thus, the image quality can be maintained, and when the plurality of images are individually observed, more accurate diagnosis can be performed.

  Hereinafter, the best mode for carrying out the present invention will be described using embodiments.

[Example]
As an embodiment, a case will be described in which the present invention is applied to a PET apparatus, and an image photographed by the PET apparatus is superimposed on an image photographed by an X-ray CT apparatus. As shown in FIG. 1, the PET apparatus 10 of the present embodiment includes a photographing unit 11, an image processing unit 12, a storage unit 13, a display unit 14, a control unit 15 for controlling each unit, and a pointing device such as a mouse. An input unit 16 including a device and a keyboard is provided. Further, it is connected to a separately provided X-ray CT apparatus 20 via the communication unit 17, and an image captured by the X-ray CT apparatus 20 can be captured and processed in the same manner by the image processing unit 12. The PET image data imaged by the imaging unit 11 and the X-ray CT image data captured from the X-ray CT apparatus 20 are superimposed on the display unit 14 via the image processing unit 12. Here, since the resolution of the PET image is usually about several mm, the matrix size of the image is about 128 × 128. On the other hand, since the X-ray CT image has a resolution of 1 mm or less, the matrix size of the image is about 512 × 512. The Therefore, before superimposing these images, the image processing unit 12 reduces the matrix size of the X-ray CT image in accordance with the PET image having a small matrix size.

  Thereafter, when the operator performs a predetermined operation with the input unit 16, either or both of the X-ray CT image and the PET image are rotated, moved, compressed, or expanded so that the images match. At this time, the history of operations such as rotation, movement, compression, and expansion (alignment information) is stored in the alignment information storage area of the storage unit 13. When both images are sufficiently matched, a predetermined operation is performed at the input unit 16, and a PET image and an X-ray CT image (positioned image) converted so that the mutual positional relationship is matched, Are stored in the image storage area of the storage unit 13 in association with the superimposed image (superimposed image). At this time, with respect to an image (in this case, an X-ray CT image) that has undergone matrix size conversion, the registration information created from the matrix size-reduced image is not stored, but the registration information storage area The registration image is reconstructed from the original data before the matrix size conversion using the information stored in, and stored.

  Thereafter, when performing observation using the superimposed image, the superimposed image is called from the image storage area of the storage unit 13 and displayed on the display unit 14 by performing a predetermined operation with the input unit 16. At this time, each alignment image stored together with the superimposed image is also read and displayed side by side with the superimposed image as shown in FIG. 2, so that the characteristics of each image can also be confirmed. At this time, since the X-ray CT image is stored in the original matrix size as described above, a high-resolution X-ray CT image can be displayed without degrading the image quality, and a more accurate diagnosis is performed. be able to.

  In the above embodiment, the superposition of the PET image and the X-ray CT image is described, but it goes without saying that the superposition of images obtained by other modalities such as MRI can be applied. Further, in the above-described embodiment, the image is aligned by the operator operating the input unit. However, the image may be automatically aligned by a program.

  In the above embodiment, the present invention is applied to the PET apparatus. However, the image processing apparatus of the present invention is not limited to the medical image capturing apparatus itself, and is not limited to the medical image capturing apparatus. May be realized by a separate workstation or personal computer. In this case, images captured by a plurality of medical image capturing devices are read into the workstation or personal computer by communication means or a storage medium, and then superimposed and stored as described above.

  Further, instead of storing the alignment image after the superposition processing as in the above embodiment, the original image before the matrix size change and the alignment information are stored in association with each other, and the alignment information is read at the next reading. May be used to reconstruct the alignment image from the original image. In addition, the superimposed image may be generated and displayed by superimposing the alignment images at the time of reading without storing the superimposed image.

The block diagram which shows the structure of the principal part of the PET apparatus which is an Example of this invention. The figure which shows the state which displayed the superimposed image and the original image in the PET apparatus which concerns on the Example. The conceptual diagram which shows the superimposition method of an image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... PET apparatus 11 ... Imaging | photography part 12 ... Image processing part 13 ... Memory | storage part 14 ... Display part 15 ... Control part 16 ... Input part 17 ... Communication part 20 ... X-ray CT apparatus

Claims (2)

A medical image processing apparatus that superimposes and stores a plurality of images captured by a medical image capturing apparatus,
a) Matrix size changing means for changing the matrix size of other images in accordance with the smallest matrix size when the matrix sizes of the plurality of images are different;
b) a registration image creating unit that creates a registration image by superimposing the plurality of images and performing conversion processing so that each image has a mutual positional relationship;
c) alignment information storage means for storing a history of conversion processing by the alignment image creating means as alignment information;
d) storage means for reconstructing and storing a registration image from original data before changing the matrix size of the plurality of images using the registration information;
A medical image processing apparatus comprising: A medical image processing apparatus that superimposes and stores a plurality of images captured by a medical image capturing apparatus,
a) Matrix size changing means for changing the matrix size of other images in accordance with the smallest matrix size when the matrix sizes of the plurality of images are different;
b) a registration image creating unit that creates a registration image by superimposing the plurality of images and performing conversion processing so that each image has a mutual positional relationship;
c) alignment information storage means for storing a history of conversion processing by the alignment image creating means as alignment information;
d) storage means for storing the alignment information and original data before changing the matrix size of the plurality of images in association with each other;
A medical image processing apparatus comprising:

Images