JP2002360563A - Medical diagnostic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid varying of the area of an object to be observed in a slice image even if a slice interval is changed. SOLUTION: An operator measures the area of lung emphysema 100A by varying thresholds t1 and t2 by manually operating a cursor 104 via a mouse 412 while looking at an image displayed on a CRT 408 and having a slice interval set to be 1 mm, e.g. as shown in Figure 1 (a). Continually, thresholds T1 and T2 are automatically set so as to respectively equalize the area of the area of lung emphysema 100B and that of the lung emphysema 100A after the slice interval is changed to 10 mm as shown in Figure 1 (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical image diagnostic apparatus, and more particularly to a computer-generated CT image,
The present invention relates to a medical image diagnostic apparatus used for extracting an observation target region from an MR image and an ultrasonic image.

[0002]

2. Description of the Related Art Conventionally, an operator traces a boundary of an observation target area with a mouse or the like while looking at an image displayed on a screen of a medical image diagnostic apparatus, and extracts an observation target.

[0003]

By the way, a CT image and M
When extracting a specific area from an R image, an ultrasonic image, etc.,
As shown in FIG. 5, when the slice interval of the three-dimensional original image is changed, there is a problem that the area of the emphysema region 100 in the subject 102 displayed on the CRT 408 changes.

That is, FIGS. 6A and 6B show three-dimensional original images in which slice intervals are set for a subject including an emphysema region. FIG. 6A shows a three-dimensional original image in which the slice interval is set to 5 mm, for example, CT5-1, CT5-2,... For the subject 102 including the emphysema region 100, and FIG. Emphysema area 1 at the same location as in FIG.
For example, CT10-
The slice interval is 10 mm as in 1, CT10-2, ...
Shows the three-dimensional original image set in FIG.

[0005] As shown in FIGS.
The area 0-2 is an image including the areas CT5-3 and CT5-4. In addition, CT10-2 and CT5-4 have different CT values in the emphysema area 100, respectively.
When the same threshold value is used when the value is set to m, there is a problem that the areas of the observation target regions obtained by performing threshold processing on the three-dimensional original image are different from each other.

The present invention has been made in view of such circumstances, and provides a medical image diagnostic apparatus capable of preventing an area of an observation target in a slice image from changing even when a slice interval is changed. With the goal.

[0007]

In order to achieve the above object, the present invention provides a medical image diagnostic apparatus for extracting an observation target from a three-dimensional original image including a volume image in which a plurality of tomographic images are stacked. First threshold setting means for manually setting a threshold for extracting an observation target from a three-dimensional original image, and second threshold setting for automatically setting a threshold for extracting an observation target from the three-dimensional original image Means, slice interval setting means for setting a slice interval of the three-dimensional original image, and extraction means for extracting an observation target from the three-dimensional original image by a threshold set by the first or second threshold setting means. The second threshold setting means comprises:
When a first threshold is set by the first threshold setting unit in relation to the first slice interval set by the slice interval setting unit, the first threshold is extracted from the three-dimensional original image by the first threshold. Volume of the observation object
The area of the observation target extracted from the image of the slice interval is determined, and then, when the slice interval is changed to the second slice interval by the slice interval setting means, the obtained volume or area of the observation target, The second threshold value is automatically set so that the volume of the observation target extracted from the three-dimensional original image or the area of the observation target extracted from the image at the second slice interval matches the threshold value of 2 It is characterized by doing.

According to the present invention, the volume of the observation target extracted from the three-dimensional original image is obtained by the first threshold value set in relation to the reference slice interval, and is obtained in advance after the slice interval is changed. The second threshold is automatically set so that the volume of the observation target matches the volume of the observation target extracted from the three-dimensional original image by the second threshold.
This makes it possible to prevent the area of the observation target from changing even when the slice interval is changed, and to more accurately measure the area of the observation target using an image with a large slice interval (thickness of the reconstruction thickness). Measurement is possible.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the medical image diagnostic apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1A and 1B are views showing display examples including a cross-sectional image of an observation target using the medical image diagnostic apparatus according to the present invention. As shown in FIG. 1A, first, a slice interval is set as thin as possible, for example, 1 mm by a slice interval setting means (not shown) for setting a slice interval of a three-dimensional original image. Subsequently, the operator enters the CRT 408
The user manually operates the cursor 104 via input means such as the mouse 412 while viewing the image displayed on the
t2 is changed, and the observation target (for example, the emphysema area 100) is changed.
A) is displayed on the CRT 408. The area of the emphysema region 100A thus displayed is automatically measured.

Next, as shown in FIG. 1B, the slice interval is set to 10 mm by the slice interval setting means. Here, the thresholds T1 and T2 are automatically set so that the area of the emphysema area 100A when the slice interval is set to 1 mm is equal to the area of the emphysema area 100B when the slice interval is set to 10 mm. I do. Once the effective thresholds T1 and T2 for the extraction of the emphysema region 100B are determined as described above, the effective thresholds T1 and T2 will be used from the next time when extracting the emphysema region with another image having a thickness of 10 mm. be able to.

Next, another embodiment of the medical image diagnostic apparatus according to the present invention will be described. As shown in FIG. 2, first, the slice interval is set to, for example, 1 mm by the slice interval setting means, and the reconstructed image having the slice interval of 1 mm is set to C.
The display is displayed on the RT 408, and the operator operates the threshold values t1 and t2 while watching the displayed image, and extracts the emphysema region 10 to be extracted.
Determine 0. When the threshold values t1 and t2 are set, pixels having CT values between t1 and t2 are collected, and the area of the emphysema region 100 having a thickness of 1 mm is obtained (step S41, and thereafter S41).
Abbreviated as ").

Subsequently, a plurality of C sheets having a slice interval of 1 mm
The emphysema area 10 in the three-dimensional original image from the area of the emphysema area 100 obtained for each T image and the slice interval 1 mm
A volume 1 of 0 is calculated (S42). This calculated volume 1
Is recorded on the magnetic disk 400 (S43).

Next, a method of setting the threshold values T1 and T2 when the slice interval is changed to 10 mm will be described. First, initial threshold values T1 and T2 in a three-dimensional original image having a slice interval of 10 mm are set (S44). Then, S4
In step 3, the volume 1 recorded on the magnetic disk 400 is read (S45). Next, pixels are extracted by threshold processing using the set thresholds T1 and T2, and the volume 2 of the emphysema region 100 in the image with the slice interval set to 10 mm is obtained (S46).

Next, the emphysema area 1 calculated in S43
00 and the emphysema area 100 calculated in S46
Then, it is determined whether “volume 1 = volume 2” is within the error range (for example, 3%) (S47). If the calculated volume is “volume 1 ≠ volume 2”, the thresholds T1 and T2
Is changed (S48), and the process returns to S46. If the calculated volume is “volume 1 = volume 2”, the effective threshold is T
1, T2, and is recorded on the magnetic disk 400 (S
49).

FIG. 3 is a flowchart showing an application example using the threshold values T1, T2 and the like. An embodiment in which an observation target area is extracted by using the valid threshold value determined in S49 of FIG. 2 for another image. Is shown. First, the magnetic disk 40
The valid threshold values T1 and T2 recorded at 0 and the acquired three-dimensional original image are read (S51, S52). Subsequently, using the effective threshold values T1 and T2 and the three-dimensional original image,
The volume of the observation target area is calculated and recorded on the magnetic disk 400 (S53).

Next, a comparison is made between the volume of the observation target area based on the image data recorded in the past and the volume of the observation target area calculated in S53 (S54). For example, when a disease whose volume does not decrease after occurrence, such as emphysema, is to be observed, if the calculated volume of the emphysema region 100 is smaller than the error (for example, 5%), the threshold is inappropriate. Is displayed on the CRT 408 (S
55). If the calculated volumes match within the range of the error, a message indicating that the disease is normal or the disease has not progressed is displayed (S56). If the calculated volume is larger than the error range, the previously recorded volume and S
The increase rate is calculated by comparing with the volume calculated in 53 (S57). Subsequently, a warning message is displayed on the CRT 408 (S58).

FIG. 4 is a block diagram showing an example of a hardware configuration of the medical image diagnostic apparatus according to the present invention. As shown in FIG. 4, the medical image diagnostic apparatus according to the present invention mainly includes a magnetic disk 400, a main memory 402, a central processing unit (CPU) 404, a display memory 406, a CR
T408, controller 410, mouse 412,
It is composed of a keyboard 414 and a common bus 416 connecting the above-mentioned components.

The magnetic disk 400 stores a three-dimensional original image obtained by an X-ray CT apparatus or the like and an image configuration program, and the main memory 402 stores a control program of the apparatus.

The CPU 404 reads the three-dimensional original image and various programs, and inputs a slice interval and thresholds t1 and t1.
Based on the input of t2, the CT image of the input slice interval is reconstructed, and image data indicating the reconstructed image is sent to the display memory 406 and displayed on the CRT 408. When the slice interval is changed after the threshold values t1 and t2 are determined, the threshold values T1 and T2 are automatically set as shown in FIG. , T2, the image subjected to the threshold processing is represented by C
Display on RT408. In addition, various processes as shown in the flowcharts of FIGS. 2 and 3 are performed.

[0021]

As described above, according to the medical image diagnostic apparatus of the present invention, even if the slice interval is changed, the area of the observation object can be kept unchanged, and an image with a large slice interval can be used. Measurement of the area of the observed object
More accurate measurement is possible.

[Brief description of the drawings]

FIG. 1 is a view showing a display example including a cross-sectional image of an observation target using a medical image diagnostic apparatus according to the present invention.

FIG. 2 is a flowchart showing another embodiment of the medical image diagnostic apparatus according to the present invention.

FIG. 3 is a flowchart showing an application example using threshold values T1, T2, etc., using the medical image diagnostic apparatus according to the present invention.

FIG. 4 is a block diagram showing a hardware configuration example of a medical image diagnostic apparatus according to the present invention.

FIG. 5 is a diagram showing a display example of an observation target using a conventional medical image diagnostic apparatus.

FIG. 6 is a view showing a three-dimensional original image in which slice intervals are set for a subject including an emphysema region.

[Explanation of symbols]

100: emphysema area, 102: subject, 104: cursor, 400: magnetic disk, 402: main memory, 404
... CPU, 406 ... Display memory, 408 ... CRT, 41
0: controller, 412: mouse, 414: keyboard, 416: common bus

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Claims (1)

[Claims] 1. A medical image diagnostic apparatus for extracting an observation target from a three-dimensional original image including a volume image obtained by stacking a plurality of tomographic images, wherein a threshold for extracting the observation target from the three-dimensional original image is manually set. First threshold setting means for setting; second threshold setting means for automatically setting a threshold for extracting an observation target from the three-dimensional original image; and slice interval for setting a slice interval of the three-dimensional original image. Setting means; and extracting means for extracting an observation target from the three-dimensional original image according to the threshold value set by the first or second threshold value setting means, wherein the second threshold value setting means When the first threshold value is set by the first threshold value setting means in relation to the first slice interval set by the setting means, the first threshold value determines whether the three-dimensional original image When the volume of the observation target to be extracted or the area of the observation target to be extracted from the image at the first slice interval is obtained, and then the slice interval is changed to the second slice interval by the slice interval setting means, The obtained volume or area of the observation target matches the volume of the observation target extracted from the three-dimensional original image by the second threshold value or the area of the observation target extracted from the image at the second slice interval. Wherein the second threshold is set automatically.