JPH04329930A - Medical diagnostic image generator - Google Patents

Abstract

PURPOSE:To obtain a projection image with hiher diagnosing capacity easy to observe by assigning an interest area on two planar images perpendicular to each other about a testee to calculate a projection image in a specified direction from a tomographic image of a multislice only for the three- dimensional area assigned. CONSTITUTION:One image is selected optionally from a number of axial tomographic images to be shown on a display device 20. A projection image projected in one direction is calculated with a projection image generator 18 from the number of axial tomographic images and a sagittal tomographic image generated is shown with a display device 20. So, a mouse 21 or a keyboard 22 is operated to assign a concern area. By assigning the area on planar images perpendicular to each other, the assignment of the area is possible by a three- dimensional cube. The projection image generator 18 performs a calculation for the generation of the projection image only for the three-dimensional area assigned from the number of axial tomographic image.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is based on MR (nuclear magnetic resonance)
The present invention relates to a medical diagnostic image creation device that creates projection images in each direction from multi-slice tomographic images obtained by an imaging device or the like.

0002

2. Description of the Related Art Conventionally, an image (projected image) that is obtained by projecting a multi-slice tomographic image obtained by an MR imaging apparatus or the like in a predetermined direction has been created by calculation. Examples of projection calculation methods include a method of simply adding all the many pixel values located on the projection line, and a maximum intensity projection method of extracting the maximum value among the many pixel values.

That is, for example, if a large number of axial tomographic images 1, 2, . . . , n are obtained as shown in FIG. 4, a three-dimensional image as shown in FIG. Therefore, by projecting in each of the projection directions A, B, and C, an axial projection image, a coronal projection image, and a sagittal projection image as shown in A, B, and C of FIG. 6, respectively, are obtained. In this case, conventionally, no projection range is specified, and a projection image is usually created for the entire area of the original image. Therefore, projection images of all regions can be obtained as in each image in FIG. Furthermore, even if a projection range is designated, a region of interest is set for one of the original images and a projected image within that region is created.

0004

[Problem to be Solved by the Invention] However, as in the past, if the projection range is not specified at all, or even if it is specified, it is only on one plane, there is no limitation in the depth direction of that plane. Therefore, there is a problem in that unnecessary parts are also projected, making it difficult to observe the images of the necessary parts. In particular, when performing MR angiography to obtain an MR angiography image in which blood vessel images have been extracted, unnecessary blood vessel images may be projected as shown in A, B, and C of FIG. 6, for example, or In addition to unnecessary blood vessel images, images of parts other than blood vessels, such as fat, are also projected, resulting in poor contrast, difficult to read images, and images that are not useful for diagnosis.

[0005] In view of the above, the present invention enables the projection range to be specified three-dimensionally, and thereby obtains a projected image that is easy to observe and has high diagnostic ability by projecting only the truly necessary parts. An object of the present invention is to provide a medical diagnostic image creation device that can perform the following steps.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the medical diagnostic image creation apparatus according to the present invention displays tomographic images or projected images of two mutually intersecting planes of a subject; A region of interest can be specified on the two displayed images. By specifying the region of interest in images on two planes that intersect with each other in this way, it is possible to specify a two-dimensional area on one of the planes and an area in the depth direction with respect to that plane.
This means that a three-dimensional area can be specified. Then, a projected image in a predetermined direction is calculated from the multi-slice tomographic image only for this designated three-dimensional region. As a result, only for a three-dimensionally limited area,
Since the projection image is calculated, the efficiency is good, and since unnecessary parts do not appear in the projection image, a projection image that is accurate, easy to read, and has high diagnostic ability can be obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of an MR imaging apparatus to which the present invention is applied.As shown in FIG. 1, a static magnetic field generator 11 and a gradient magnetic field generator 12 are provided, and a gradient magnetic field is can be arbitrarily superimposed. A radio frequency signal is applied by an excitation device 13 to a subject placed in a static magnetic field to selectively excite nuclear spins within a specific slice plane of the subject, and the NMR signals generated there are received by a receiving device 14. The data is received and taken into the computer 15, and the data is stored in the storage device 17. By processing the data thus collected by the image reconstruction device 16, an image of the selectively excited slice plane is reconstructed.
This is sent to the display circuit 19 and displayed on the display device 20.

Here, the computer 15 manipulates the excitation signal waveform and the gradient magnetic field waveform and controls the pulse sequence to produce multi-slice tomographic images 1, 2, . . . in the axial direction of the subject's head as shown in FIG. , n. The projection image creation device 18 calculates a projection image in a predetermined direction from the multi-slice tomographic image stored in the storage device 17. Any of the created projection images and axial tomographic images are sent to the display circuit 19 and displayed on the display device 20. A coordinate input device such as a mouse 21 and an input device such as a keyboard 22 are connected to the computer 15.

In such an MR imaging apparatus, first, a large number of axial tomographic images (original images) 1, 2, . . .
, n is arbitrarily selected and displayed on the display device 20, for example, as shown by A in FIG. Further, a projection image projected from a large number of axial tomographic images (original images) 1, 2, . . . , n in one direction, for example, in a projection direction C shown in FIG. At this time, a projection image of the entire area is calculated without any limitation of the area, and a sagittal projection image as shown in B in FIG. 2 is created. The created sagittal tomographic image is then displayed on the display device 20. Therefore, the mouse 21 and keyboard 22
By operating , a region of interest as indicated by diagonal lines on these displayed images is specified.

By specifying the region of interest on the axial tomogram, it is possible to specify a two-dimensional region in the axial cross section of the subject, and by specifying the region of interest on the sagittal projection image, This means that a region in the depth direction has been specified with respect to the above axial cross section. Therefore, by specifying an area on two plane images that intersect with each other, it is possible to specify a three-dimensional area.

[0011] When a region is designated in this way, the projection image creation device 18 performs projection image creation calculations only for the designated three-dimensional region from a large number of axial tomographic images. Here, projection calculation is performed in the direction A in FIG. 5 to obtain an axial projection image as shown in C in FIG. In this case, since projection calculation is performed only for a limited three-dimensional area, calculation efficiency is high and accuracy is high. The obtained axial projection image does not show any unnecessary parts, as shown in C in Figure 2, so it is only a blood vessel image limited to the area around the viral ring, which is easy to observe and has high diagnostic ability. It becomes an image.

First, the projection image creating device 18 generates projection images of the entire area in two directions, for example, an axial projection image in direction A in FIG. 5 and a coronal projection image in direction B in FIG. B, and display them on the display device 20.
, and on these displayed images, press the mouse 21.
It is also possible to specify a region of interest as indicated by diagonal lines by operating the keyboard 22 or by operating the keyboard 22. Then, for the three-dimensional area designated by these, the projection image creation device 1
8 to calculate the projection in the direction C in FIG. 5, a sagittal projection image as shown in C in FIG. 3 is obtained. in this case,
This is a sagittal projection image of a desired three-dimensional region of the left hemisphere. In this way, a projected image of the desired area divided into hemispheres is obtained.

[0013] In this way, it is possible to designate a three-dimensional region by specifying the region of interest on the two images displayed on the display device 20, so it is easy to visually specify the region in three dimensions while looking at those images. Can be specified dimensionally.

[0014] The image for specifying the region is not limited to these, and a tomographic image taken in a cross section in an arbitrary direction or a projected image in an arbitrary direction can be used.

[0015]

[Effects of the Invention] As described above with respect to the embodiments,
According to the medical diagnostic image creation device of the present invention, a three-dimensional region of interest can be easily specified on the image based on vision;
A projected image in a predetermined direction can be obtained from the multi-slice tomographic image only for the designated three-dimensional region. Therefore, since unnecessary parts do not appear in the projected image, accurate, easy-to-read, and highly diagnostic projection images can be obtained, and projection images are calculated only for three-dimensionally limited areas, increasing efficiency. good.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of each image in the same embodiment.

FIG. 3 is a diagram showing another example of each image in the same embodiment.

FIG. 4 is a diagram showing a multi-slice original image.

FIG. 5 is a diagram for explaining a projection direction.

FIG. 6 is a diagram showing each conventional projection image.

[Explanation of symbols]

11 Static magnetic field generator 12
Gradient magnetic field generator 13
Excitation device 14
Receiving device 15 Computer 1
6 Image reconstruction device 17
Storage device 18
Projection image creation device 19 Display circuit 20 Display device 21
mouse

Claims (1)

[Claims] 1. Means for displaying images of two mutually intersecting planes of a subject; means for specifying a region of interest on the two displayed images;
1. A medical diagnostic image creation apparatus, comprising projection image calculation means for calculating a projection image in a predetermined direction from a multi-slice tomographic image only for a dimensional region.