JPH07313467A - Diagnostic image display device - Google Patents

Abstract

PURPOSE:To enable a high-precision diagnosis without increasing the burden on a doctor even when a tomographic image is utilized by providing a display means, a display control means which divides plural tomographic images into a 1st and a 2nd group and supplies them, group by group, to a display means, and enabling a 1st and a 2nd diagnosing persons to observe the tomographic images. CONSTITUTION:A bed 3 moves continuously in the direction of the body axis during the continuous rotation of an X-ray generation part 1 and an X-ray detection part 4, and a helical scan is added. The signal outputted from the X-ray detection part 4 is processed by a data gathering system and converted into a digital quantity, which is supplied to a preprocessing part 6. The preprocessing part processes it by logarithmic conversion and correction and sends the resulting data as projection data to a reconstitution part 8, which performs reconstitution arithmetic for the projection data to reconstitute an image (axial tomographic image). The reconstituted tomographic image is stored in an image storage part 9, and a display control part 10 reads plural tomographic images out of the image storage part 9 and supplies them divisionally as the 1st and 2nd group to a display part 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diagnostic image display device for displaying a tomographic image used for diagnosis.

[0002]

2. Description of the Related Art Up to now, mass screening for lung cancer has been performed by taking a plain X-ray image and reading it by a doctor. However, it has been pointed out that the detection rate of lung cancer is not sufficient in diagnosis based on simple X-ray images. On the other hand, it is known that a tomographic image taken by a computer tomography apparatus (hereinafter abbreviated as CT apparatus) has a higher lung cancer detection rate than a simple X-ray image. Therefore, it is considered to perform a mass screening for lung cancer using a CT device.

However, there is a problem that must be solved even in mass examination by tomographic image. One of them is the problem of shooting time. Many people undergo group examinations as compared to individual examinations at medical institutions. Furthermore, the number of examinees tends to increase as Japan shifts to an aging society. Therefore, it is necessary to shorten the imaging time in order to examine a large number of examinees in a short time. However, since it takes more time to capture an image with a CT apparatus than a simple X-ray imaging, it has been practically impossible to apply the CT apparatus to a mass examination. This is CT
The main reasons were the throughput of the equipment and the lack of capacity of the X-ray tube. However, recently, a CT device called a so-called helical scan system has been developed to improve the throughput, and the capacity of the X-ray tube has been increased so that a tomographic image can be taken in a relatively short time. By using the CT device of the helical scan type capable of performing such high-speed imaging, the problem of imaging time in group medical examination can be solved.

However, the group medical examination by the CT apparatus has a problem in that not only the photographing time but also the number of images that the doctor must read is large. A simple X-ray image can be used to read, for example, the entire lung field, which is a diagnostic site, but a single CT image is an axial tomographic image orthogonal to the body axis, and therefore multiple tomographic images are obtained. Without it, the entire lung field cannot be read. Therefore, 1
Since it is necessary to read a plurality of images for each subject, the burden on the doctor is increased and the reading time is longer than when a simple X-ray apparatus is used. Note that, in order to reduce the number of tomographic images, if the CT of the helical scan method is used with a long bed-feed pitch for imaging, the actual slice width becomes thicker and the image quality deteriorates, and abnormal cases (shadows) do not appear. However, there is a drawback that the diagnostic accuracy deteriorates.

[0005]

As described above, in the related art, it is necessary to interpret a large number of tomographic images as compared with an X-ray image in a diagnosis using a large number of tomographic images, particularly in a mass screening. Therefore, there is a problem that it takes time and a great burden is placed on the doctor.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a diagnostic image display apparatus capable of performing highly accurate diagnosis without increasing the burden on a doctor even if a tomographic image is used.

[0007]

A diagnostic image display apparatus according to the present invention includes a display unit and a plurality of tomographic images for displaying first and second groups.
It is characterized in that it is provided with a display control means for dividing into groups and supplying the display means for each group, and a plurality of tomographic images can be observed by the first and second diagnosticians.

[0008]

According to the present invention, the photographed tomographic image of the subject is supplied to the display means in accordance with a predetermined rule, and two doctors make a diagnosis based on the supplied tomographic image. Therefore, the burden on one doctor can be reduced by half without degrading the diagnostic accuracy.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a diagnostic image display device according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of this embodiment. Here, as an example, a system will be described in which a large number of tomographic images captured by using a CT device of a helical scan system are displayed and a diagnosis is performed based on the displayed tomographic images.

In the CT apparatus, a bed 3 on which the subject 2 is placed and an X-ray that irradiates the subject 2 with a fan-shaped X-ray beam.
It has a line generation unit 1 and an X-ray detection unit 4 which is composed of detector arrays arranged in an arc shape and detects an X-ray beam transmitted through a subject 2. The X-ray detector 4 collects projection data indicating the X-ray transmittance. Here, the projection data at an angle of 360 ° or more can be continuously collected so that the helical scan can be executed. That is, although not shown, the X-ray generation unit 1 and the X-ray detection unit 4
The gantry rotating part for holding the and is attached to the gantry fixing part via a slip ring, and the X-ray generating part 1 can continuously rotate around the subject 2. The bed 3 continuously moves in the body axis direction during continuous rotation of the X-ray generation unit 1 and the X-ray detection unit 4. As a result, the helical scan is performed. As the imaging conditions given to the CT apparatus, in this embodiment, the slice width is 10 mm and the bed feeding speed is 20 mm / revolution.

The signal output from the X-ray detector 4 is amplified by a data acquisition system (DAS) (not shown),
Signal processing such as integration and A / D conversion is performed, converted into a digital amount, and supplied to the preprocessing unit 6. The pre-processing unit 6 performs logarithmic conversion and correction on the data, and then reconstructs it as projection data.
Send to. The reconstruction unit 8 performs reconstruction calculation including convolution calculation and back projection calculation on the projection data to reconstruct an image (axial tomographic image). It is known that in a helical scan type CT apparatus, the slice pitch and slice position of an image to be reconstructed can be set to almost arbitrary values, and generally, an image having a shorter pitch is easier to detect lung cancer. But,
Even if the pitch is extremely shortened, the detectability does not improve so much, and the shorter the pitch, the more the number of images increases, and the doctor's burden of interpreting the image increases. In particular, in the case of a group medical examination, since the number of examinees is large, the number of images that can be interpreted, that is, the pitch of images to be reconstructed is naturally limited. Therefore, the doctor obtains an appropriate pitch in advance and sets the value. Here, the pitch of the image to be reconstructed (reconstruction pitch) is set to 5 mm. The reconstruction unit 8 reconstructs an image with the set pitch.

The reconstructed tomographic image is stored in the image storage unit 9. The display control unit 10 reads out a plurality of tomographic images stored in the image storage unit 9, divides them into first and second groups, and supplies them to the display unit. The display unit 11 displays a tomographic image used for diagnosis. In addition, a console 12 is provided on the display unit 11.
Are connected.

The CPU 5 is a CT device and system bus 7.
Connected to the preprocessing unit 6, the reconstruction unit 8, the image storage unit 9,
The display control unit 10 is controlled. The system bus 7 is a bus for mainly transferring image data such as projection data and reconstructed images.

The operation of this embodiment will be described. First, as described above, the imaging conditions (slice width 10 mm, feeding speed of the bed 3 20 mm / revolution) are set, and tomographic images of the lung fields of a large number of examinees are taken by helical scanning, and a large number of images are taken at a pitch of 5 mm. An axial tomographic image with a slice width of 10 mm is reconstructed. The reconstructed image is stored in the image storage unit 9.

Interpretation may be performed at the same time as photographing,
Usually, it is done collectively after shooting. Display control unit 10
Reads a tomographic image from the image storage unit 9 during image interpretation, and displays a plurality of tomographic images of each examinee according to a predetermined rule.
Supply to 1.

FIG. 2 is a diagram showing how the display control unit 10 divides a plurality of tomographic images into groups. The display control unit 10 alternately divides a plurality of tomographic images I _n (n = 1 to 2 m) at consecutive slice positions reconstructed for one subject into two groups, and divides them into A and B groups. -P. The images of the A group are images I _i (i = 1, 3, ..., 2 m) whose image numbers corresponding to the slice positions are odd numbers.
−1), and the image of the B group is the image I _{i + 1} having an even image number corresponding to the slice position. A method of dividing a plurality of tomographic images into groups is specified in advance by the operator console before the examination. Also, once specified, it will be registered.

When the first doctor interprets the image first, the display unit 11 displays the odd image I _i of the A group.
Next, when the second doctor interprets the image, B is displayed on the display unit 11.
An even image I _{i + 1 of the group} is displayed. If the reconstruction pitch is 5 mm, the pitch of the image displayed by the display unit 11 is 10 mm. That is, the entire tomographic image with the slice width of 10 mm is displayed every 10 mm. This is similar to the double interpretation that is conventionally performed for a simple X-ray image. In double interpretation, two doctors interpret the same image of the subject.

In the image interpretation method of this embodiment, the doctor is tired by examining a large number of examinees in the group examination,
This can prevent the diagnostic accuracy from deteriorating due to this. For example, even if one doctor overlooks an abnormal case, it can be expected that another doctor will not overlook it.

As a method of sending an image display at the time of image interpretation, a doctor may operate the operation console 12 to send an image every time one image is displayed, or automatically at a constant display time interval. The image may be sent to the user.

FIG. 3 is a table showing a comparison according to image interpretation methods in lung cancer mass screening. The comparison is performed based on the result of the image interpretation for each method of method numbers 1 to 5 by various reconstruction pitches and image reading methods. Moreover, the imaging conditions of the CT apparatus are constant regardless of the method.

Regarding the reconstructed pitch, an image with an almost arbitrary pitch can be reconstructed with a CT apparatus, but 5 mm and 10
In the case of mm, the reading method is called “double”, which is a double reading in which two doctors read the same image of the same subject in duplicate, and the reading method of the present embodiment is called “this method”. "Single" is the method of reading images by only one doctor. Regarding the number of images read, the total number of images read by the doctor, but here,
This is a relative value when the number of interpretations of method number 5 is 1.

Regarding the diagnostic accuracy (detection accuracy of lung cancer),
Although quantitative evaluation is not possible, the following can be said qualitatively. (1) Regarding method 4 and method 5, method 4 is slightly more accurate.

(2) In method 3 and method 4, method 3 is slightly more accurate. (3) Regarding method 1 and method 3, method 1 is slightly more accurate. (4) Regarding method 1 and method 2, method 1 is slightly more accurate.

(5) In method 2 and method 3, method 2 is slightly more accurate. From the above, regarding the diagnostic accuracy, the method 1 is the best and the next is the method 2, but it is considered that there is little difference between the method 1 and the method 2 because the reconstruction pitch is the same. On the other hand, 1
Method 1 has the largest number of interpretations per person. Especially in the case of group medical examination, since the number of examinees is large, it is a burden on the doctor in the method 1 that a large number of images are read per person. Therefore, overall, method 2 is considered to be the most appropriate.

As described above, according to the present embodiment, it is possible to provide a diagnostic image display apparatus capable of highly accurate diagnosis without increasing the burden on the doctor even if a tomographic image is used for mass screening for lung cancer.

The present invention is not limited to the above-mentioned embodiments, but can be implemented with various modifications. In the present embodiment, the images of the two groups are displayed on one display device while being shifted in time, but the two display devices are provided and the image of the A group is displayed on the first display device. , B group images may be displayed on the second display device. Further, although the above description has been made about the diagnosis at the time of mass screening for lung cancer, it is not limited to this.
The present invention can be applied to general individual diagnosis, and the object of diagnosis is not limited to lung cancer, and can be applied to any site diagnosis. Also, as a projection data acquisition method, a CT adopting a Rotate / Rotate (R / R) method
The case of the apparatus has been described, but the stationery / rotate (Stationary / Rotate, S / R) system, the nutate / rotate (N / R) system CT
It may be a device. Further, it may be a CT device of fixed position scanning instead of helical scanning.

The image storage unit 9 can save capacity by compressing and storing a plurality of tomographic images that it holds. In that case, first, a difference image of adjacent images is obtained for each slice. If the slice pitch is short, the adjacent images are similar to each other, and the pixel value of the difference image is small. Usually, most of the CT values in the range of ± 1000 fall within the difference value of ± 127. This is reversibly compressed. The lossless compression is performed because, for example, if the lossy compression is performed, the restored image deteriorates, which may affect the diagnosis. When the difference image having a small pixel value is compressed, the compression rate increases, and the data size required for storage is small, so the capacity of the image storage unit 9 can be saved. Further, the tomographic image to be displayed is not limited to the CT image, and a PET / SPECT image, an ultrasonic tomographic image, or an MR image may be displayed.

[0028]

According to the present invention, it is possible to provide a diagnostic image display device capable of highly accurate diagnosis without increasing the burden on the doctor even if a tomographic image is used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a diagnostic image display device according to the present invention.

FIG. 2 is a diagram showing how a plurality of tomographic images are divided.

FIG. 3 is a diagram showing a comparison according to image interpretation methods.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... X-ray generation part, 2 ... Subject, 3 ... Bed, 4 ... X-ray detection part, 5 ... CPU, 6 ... DAS, 7 ... System bus, 8 ...
Reconstruction unit, 9 ... Image storage unit, 10 ... Display control unit, 11 ...
Display unit, 12 ... Operation console.

Claims (2)

[Claims] 1. A diagnostic image display apparatus for displaying a plurality of tomographic images, comprising: a display means; the plurality of tomographic images divided into first and second groups, and the display means for each group. A diagnostic image display apparatus comprising: a display control unit that supplies the plurality of tomographic images to the first and second diagnosticians. 2. The plurality of tomographic images are tomographic images at slice positions at regular intervals taken by a helical scan type computer tomography apparatus, and the display control means is a tomographic image at each slice position. Is alternately divided into the first and second groups, and the diagnostic image display device according to claim 1.