JPH0824238A - Image reconstruction device - Google Patents

Abstract

PURPOSE:To obtain immediately a projected image etc., with a tomographic image after photographing by providing a means for treating a raw data on a memory and reconstituting the tomographic data and a means for preparing an image from the tomographic image data when the reconstituted tomographic data exists on a memory. CONSTITUTION:A computer 5 performs a photographic sequence by controlling an gradient magnetic field generating apparatus 2 and an exciting apparatus 3 and raw data obtd. there on a number of sliced faces are stored in a memory 6. A tomographic image reconstitution apparatus 7 reconstitutes the tomographic images on each sliced face by performing two dimensional Fourier Transformation of raw data on the memory 6. A projected image forming apparatus 9 prepares projected images in various directions by operating the image data when the image data of the original image exist on the memory 6. It is possible thereby that when the tomographic image is reconstituted from the original data, the projected image is immediately prepd. and displayed without reading out the image data from the outside storing apparatus.

Description

Detailed Description of the Invention

[0001]

This invention relates to an MRI apparatus and an X-ray C
The present invention relates to an image reconstruction device such as a T device.

[0002]

2. Description of the Related Art In an MRI apparatus, an X-ray CT apparatus or the like, data is usually collected on one plane of a subject, and an image on the plane is reconstructed as a tomographic image from the data. As the image reconstruction algorithm, Fourier transform method or back projection method is used. If such a tomographic image is obtained for a large number of adjacent slice planes, a three-dimensional array of image data will be reproduced. Once such a stereoscopic image is obtained, it can be projected in various directions to obtain a projected image, or image data on an arbitrary slice plane can be collected to obtain a tomographic image of the arbitrary slice plane. This is often done as well, since it allows the observation of images useful for diagnosis.

For example, MRA (MR Angiography) is
The blood vessel image is imaged by an imaging sequence that emphasizes the flow portion such as the TOF (Time Of Flight) method. However, since the tomographic image only knows the shape of one cross section of the blood vessel, the image shows the doctor's diagnosis. Can not be used for interpretation. Therefore, usually 32
1 or 64 slice images are obtained and MI
P (Maximum Intensity Projectin) processing is performed to create a projection image in which only the blood vessel portion is projected on an arbitrary surface such as a sagittal surface or a coronal surface.

Conventionally, a process of reconstructing a tomographic image from raw data is first performed, and a large number of tomographic images obtained there are temporarily stored in an external storage device such as a hard disk.
After that, a large number of tomographic images are read from the storage device, and a process such as the MIP process described above is performed to create a projected image.

[0005]

However, the process of reconstructing a tomographic image is first performed as described above, the obtained tomographic image is temporarily stored in an external storage device, and then read out to create a projected image. With such a configuration, there is a problem that it takes time to write to and read from the external storage device, and the projection image and the like cannot be immediately observed with reconstruction of the tomographic image. That is, since the reconstructed image data has a large amount of data and a large number of images, it takes a considerable time to read it from the hard disk or the like and develop it on the memory of the computer. In addition, it is not only troublesome to perform the process of reconstructing a tomographic image after imaging (raw data collection), recording it on a hard disk, and then reading it again to perform the process of creating a projection image. It is not possible to observe the projected image immediately.

[0006] In view of the above, an object of the present invention is to provide an image reconstructing apparatus improved so that a projection image and the like can be immediately obtained together with a tomographic image after imaging.

[0007]

To achieve the above object, in an image reconstruction apparatus according to the present invention, a tomographic image reconstruction means for reconstructing a tomographic image by processing raw data on a memory, It is characterized in that it is provided with an image creating means for performing a process of creating a predetermined image from the tomographic image data when the data of the reconstructed tomographic image exists in the memory.

The image creating means for creating a predetermined image from the tomographic image data when the reconstructed tomographic image data exists in the memory creates a projected image by the maximum intensity projection process. It may be done.

Further, the image creating means for creating a predetermined image from the tomographic image data when the data of the reconstructed tomographic image is present in the memory is on another slice plane. It is also possible to collect the image data located at the position to create a tomographic image of the slice plane.

The raw data may be data obtained by the MRI apparatus, and the tomographic image reconstructing means may reconstruct the tomographic image by the two-dimensional Fourier transform method.

The raw data may be data obtained by an X-ray CT apparatus, and the tomographic image reconstructing means may reconstruct a tomographic image by the back projection method.

[0012]

When the tomographic image is reconstructed by processing the raw data on the memory, the reconstructed tomographic image data is
Immediately after the reconstruction process, all of them exist in the memory.
Therefore, by performing processing such as projection image creation when the image data after this reconstruction processing exists in the memory, it does not require time to write to or read from a storage device such as a hard disk, A projection image and the like can be immediately obtained together with the tomographic image, which enables quick observation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. The embodiment shown in FIG. 1 is an application of the present invention to an MRI apparatus. As shown in FIG. 1, the MRI apparatus includes a static magnetic field generation device 1, a gradient magnetic field generation device 2, and an excitation device 3. A subject (not shown) is placed in the static magnetic field and An NMR signal is generated by exciting a subject with a high frequency signal while superimposing a pulsed gradient magnetic field. Then, the NMR signal is received by the receiving device 4, taken into the computer 5, and stored in the memory 6 as raw data.

The computer 5 performs an imaging sequence such as a gradient echo method or a spin echo method by controlling the gradient magnetic field generating device 2 and the exciting device 3, and stores the raw data obtained in a large number of slice planes therein. 6 to be stored. The tomographic image reconstruction device 7 reconstructs a tomographic image on each slice plane by performing two-dimensional Fourier transform on the raw data on the memory 6. This allows, for example, FIG.
An original image 21 composed of tomographic images on a large number of slice planes is obtained as shown in FIG. The data of the original image 21 exists in the memory 6 immediately after the image reconstruction processing, and is later written in the external storage device 8 such as a hard disk.

The projection image creating device 9 creates a projection image by projecting the original image 21 obtained as a tomographic image on a large number of slice planes in various directions as shown in FIG. This figure 2
Then, the three-dimensionally arranged image data of the original image 21 is
Transverse image 22 obtained by projecting on the transverse plane
, A coronal image 23 obtained by projecting on the coronal plane, and a sagittal image 24 obtained by projecting on the sagittal plane are illustrated.

When the image data of the original image 21 still exists in the memory 6, the projection image creating device 9 operates the image data to create projection images in the various directions described above. The projected image is created on the memory 6 and later stored in an external storage device 8 such as a hard disk. The tomographic image (original image 21) and projection image (transverse image 22 etc.) created on the memory 6 are passed through the display circuit 10 to C
It is sent to the display device 11 such as an RT device and displayed. Therefore, if the tomographic image is reconstructed from the raw data, it is possible to immediately create and display the projected image without reading the image data from the storage device 8.

The mouse 12 is for inputting an arbitrary position on the image displayed on the display device 11, and the keyboard 13 is for inputting characters and numerical values. By operating the mouse 12 and the keyboard 13, various processing instructions can be given.

In this embodiment, the MRA by the TOF method is performed to obtain an original MRA image in which the blood vessel portion is emphasized, and while this is on the memory 6, this is orthogonally crossed by the MIP method.
Three MIP images of transverse, coronal, and sagittal are obtained by projecting in the direction, and these are displayed and written in the storage device 8. Therefore, it is possible to immediately obtain a MIP image that can be interpreted together with the MRA original image reconstructed after imaging without waiting for the time for reading the original image from the storage device 8 for the projection processing, and thereby quickly examine the subject. It becomes possible to interpret the blood vessel image of. In this embodiment, since the MIP images in the reference three directions are automatically created, the mouse 12 and the keyboard 13 are used to input the instruction for creating the MIP image.
There is no need to operate.

Although the projection image is created by the MIP method in the above, when the image is not MRA, image data located at a predetermined cross section of the original image 21 is taken out to create a tomographic image of a predetermined slice plane. May be. The computer 5 executes the process of creating the tomographic image and the above-described projection image.
You can also use The projected image is the transverse,
It can also be created by projecting in any direction other than the three directions of coronal and sagittal.

In the above, the embodiment in which the present invention is applied to the MRI apparatus has been described, but it is also applicable to an X-ray CT apparatus or the like. In the case of an X-ray CT apparatus, projection data obtained by projecting a subject with X-rays from various directions is obtained as raw data, and by back-projecting the projection data, a tomographic image on a slice plane is reconstructed. Since the raw data and the data of the reconstructed image are also placed on the memory, if the process of creating a tomographic image on a projected image or another slice plane in the same manner as above when this image data is on the memory, The projected image can be observed immediately without waiting for reading from the hard disk. Furthermore, the present invention can be applied to an emission CT apparatus that performs image reconstruction similar to the X-ray CT apparatus.

[0021]

As described in the above embodiments, according to the image reconstructing apparatus of the present invention, if the tomographic image is reconstructed, the desired projection image can be immediately obtained from the image data without reading from the hard disk or the like. Etc. can be created.

[Brief description of drawings]

FIG. 1 is a block diagram of an MRI apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating creation of a projected image in the same embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Static magnetic field generator 2 Gradient magnetic field generator 3 Excitation device 4 Receiving device 5 Computer 6 Memory 7 Tomographic image reconstruction device 8 Storage device 9 Projection image creating device 10 Display circuit 11 Display device 12 Mouse 13 Keyboard 21 Original image 22 Transverse Statue 23 Coronal Statue 24 Sagittal Statue

Claims (1)

[Claims] 1. A tomographic image reconstructing means for reconstructing a tomographic image by processing raw data in the memory, and the tomographic image when the data of the reconstructed tomographic image exists in the memory. An image reconstructing apparatus, comprising: an image creating unit that creates a predetermined image from data.