JPS5910217B2 - CT device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention obtains projection data from multiple directions about a subject, and performs image reconstruction processing based on the projection data to reconstruct data according to the constituent materials of each unit part, that is, pixel, constituting a tomographic plane of the subject. CT (compute
edtomography) device.

In a CT apparatus, not only image information of the entire imaging surface obtained by image reconstruction is displayed, but also an area where a particularly detailed observation is desired, i.e., after observing the displayed image of the entire imaging surface, is displayed. Some devices allow you to designate a region of interest and then display the region of interest in an enlarged manner.

When setting a region of interest in the CT apparatus or diagnosing a region of interest, it is preferable to know the distribution state of CT values within the set region of interest. Conventionally, in such cases, the state of distribution has only been determined objectively using statistical methods such as calculating the average value or standard deviation of CT values within the region of interest; It was difficult to judge visually. The present invention was made based on the above circumstances, and an object of the present invention is to provide a CT apparatus that can easily grasp the distribution state of CT values on an image.

That is, the feature of the present invention is that by setting a desired CT value range, a portion having a CT value that falls within the set range is displayed with a predetermined display gradation. Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the figure, 1 is an upper limit value setter for setting the upper limit of the CT value setting range, 2 is a lower limit value setter for setting the lower limit of the CT value setting range, and 3 is the upper limit value setter for setting the lower limit of the CT value setting range. A memory in which CT image data consisting of CT values for each image is stored; 4 is a memory controller for controlling reading/writing of the memory 3; particularly, in this case, a memory controller for controlling reading of image data in the memory 3; 5 is an enlargement Setting of the region of interest desired to be displayed, etc., i.e. position of the region of interest in the X direction, Y
A region of interest setting device 6 for setting the directional position, size in the X direction, and size in the Y direction passes only data within the region of interest set by the region of interest setting device 5 out of the image data sequentially read out from the memory 3. 7 is an upper limit comparator for comparing the upper limit set by the upper limit value setter 1 with the CT value of the image data in the region of interest that has passed through the gate circuit 6; 8 is a lower limit value setting 9 is a lower limit comparator for comparing the lower limit set by the lower limit value set by the upper limit comparator 7 with the CT value of the image data determined to be less than the upper limit value by the lower limit comparator 8; A brightness converter that replaces the image data with the scheduled image data (CT value), for example, the highest brightness in this case; 10 is the image data within the set region of interest determined to be equal to or higher than the upper limit by the upper limit comparator 7; and lower limit comparator 8 11 is a memory controller 4 that displays an image using the image data within the set region of interest determined to be below the lower limit value and the image data whose brightness has been converted by the brightness converter 9;
, image display 10, etc., is a clock generator that provides a synchronization clock signal for synchronizing the timing of the entire system to each of the above-mentioned parts of the system, such as the image display 10.

Next, the operation in the above configuration will be explained.

First, in the case of normal display of all image data, all settings by the upper limit setter 1, lower limit setter 2, and region of interest setter 5 are not performed, and the gate circuit 6, upper limit comparator 7, lower limit comparator 8, and With the brightness converter 9 inactive, the image data from the memory 3 is sequentially read out by the memory controller 4 and displayed on the image display 10. In addition, if there is a portion of the CT image displayed on the image display 10 that requires detailed observation, the region of interest setting device 5 sets the region of interest in the X direction, Y direction, and X direction. Set the size and Y direction size.

As a result, a region of interest mark is displayed on the display screen by mark display means (not shown). Then, when the system is switched to the enlarged display mode, only the image data within the region of interest that has passed through the gate circuit 6 is provided to the image display 10, and the region of interest is displayed in an enlarged manner.
At this time, if the CT value range is set by the upper limit value setter 1 and the lower limit value setter 2, the following operation is performed. First, the image data in the region of interest that has passed through the gate circuit 6 is compared with the upper limit value of the CT value setting range by the upper limit comparator 7, and the image data having a CT value higher than the upper limit value is directly displayed on the image display 10. C below the upper limit value
Those with T values are provided to a lower limit comparator 8. In the lower limit comparator 8, the image data given from the upper limit comparator 7 is compared with the lower limit value of the setting range, and those with CT values below the lower limit value are directly provided to the image display 10, and those with CT values above the lower limit value are Those with values are provided to a brightness converter 9. The brightness converter 9 converts the image data provided from the lower limit comparator 8 into image data with the highest brightness set in advance, and provides this to the image display 10. Therefore, the image display 10 displays an image in which only the portion of the enlarged image of the region of interest whose CT value falls within the set range is converted to the highest brightness. That is, in the above-described configuration, the upper limit value setter 1 and the lower limit value setter 2 set the desired C.
It constitutes a CT value setting means for setting the T value range by external operation, and uses an upper limit comparator 7 and a lower limit comparator 8 to determine the C value corresponding to the CT value range set by the C value range setting means.
A discrimination means for discriminating pixels having a T value is configured, and a luminance converter 9 changes the display gradation of the pixel discriminated by the discrimination means to a scheduled display gradation regardless of its CT value. It constitutes display gradation changing means for image display.

In this way, the region of interest is displayed in which only the portion that falls within the preset CT value range is displayed at maximum brightness (in white), so the distribution of CT values within the preset range can be easily grasped. By appropriately setting the CT value range, diagnosis within the region of interest can be performed extremely accurately.

Note that in the above description, the specific setting range is set to a specific brightness in the enlarged display of the region of interest, but if the same display is performed in the entire image (non-enlarged) display,
It is possible to understand the entire CT value distribution, and it is also possible to easily set a region of interest when enlarging display afterwards.

Furthermore, in addition to setting the brightness within the setting range to a specific brightness such as the maximum brightness, it is sufficient to display the display at a specific display gradation that can be distinguished from others. In addition, although the above configuration is shown as a functional block,
As long as the functional configuration is equivalent to this, other hardware configurations or configurations using software such as a computer may be used.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with various modifications without changing the gist thereof.

As described above in detail, according to the present invention, it is possible to provide a CT apparatus that can easily grasp the distribution state of CT values on an image.

[Brief explanation of the drawing]

The figure is a process diagram showing the configuration of one embodiment of the present invention. 1... Upper limit value setter, 2... Lower limit value setter, 3... Memory, 4... Memory controller, 5...・Region of interest setter, 6...
Gate circuit, 7... Upper limit comparator, 8...
・Lower limit comparator, 9... Brightness converter, 10...
...Image display, 11...Clock generator.

Claims (1)

[Claims] 1 Obtain projection data about the subject from multiple directions within the same plane, and perform image reconstruction processing based on the projection data,
A CT value corresponding to the constituent material of each unit part constituting the tomographic plane of the subject on the plane is determined, and the CT value is supplied as image data corresponding to a display gradation to an image display means to display the tomographic plane of the subject. A CT device that displays images includes a CT value range setting means for setting a desired CT value range by external operation, and image data of CT values corresponding to the CT value range set by the CT value range setting means. , a discriminating means for discriminating among the image data supplied to the image display means, and changing the image data discriminated by the discriminating means to a scheduled display gradation regardless of the original CT value and replacing it with the original image data. and display gradation changing means for supplying the image to the image display means.