JP2000210284A - Ultrasonic diagnostic system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the volume of calculation and errors as far as possible by processing an ultrasonic image to calculate the heart chamber area from the profile of the heart chamber, elliptically approximating the profile image to calculate the length of one of major and minor axes, and calculating the heart chamber volume from the heart chamber area and the length of one axis. SOLUTION: An ROI generator 16 generates an ROI to define the periphery of a profile extraction range. A gate circuit 14 extracts only data belonging to the ROI according to the address of the ROI generated by the ROI generator 16. A profile extracting part 18 extracts the profile image of, for instance. the left ventricle using various processes such as filtering, compressing and extending, digitizing, etc. An area calculating part 20 counts pixels, i.e., the number of data, in the profile to calculate the area off the hollow in the left ventricle. A length calculating part 22 calculates the length of the major axis when the profile is elliptically approximated. A volume calculating part 26 calculates the volume according to an equation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to measurement of cardiac function.

[0002]

2. Description of the Related Art Ejection rate (Ej
Section Fraction: EF) is used. Ejection rate EF
Is generally defined as EF = (EDV−ESV) / EDV × 100 (%) (1) using the left ventricular volume EDV at the end diastole and the left ventricular volume ESV at the end systole.

Conventionally, when measuring the ejection fraction using ultrasonic diagnosis, first, an ultrasonic image corresponding to a left ventricle cross section is displayed. On the ultrasonic image, the left ventricle is divided into a plurality of small rectangular areas, and a partial volume is obtained by assuming a rotating body for each area, and finally, each partial volume is added to obtain an approximate value. The left ventricular volume is calculated. Then, the ejection fraction is calculated from the left ventricular volume at the end diastole and the end systole according to the above formula (1).

[0004]

However, in the above-mentioned conventional calculation method, the amount of calculation is large and the processing load is increased. Therefore, it was conceivable to simply approximate the left ventricle cross section with an ellipse and to approximate the left ventricle as the volume of an ellipsoid from the lengths of its major axis and minor axis, but in that case, the error may increase. there were.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to calculate a heart chamber volume with a small amount of calculation and as few errors as possible.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a contour image generating means for processing an ultrasonic image to generate a contour image of a heart chamber, and a heart chamber based on the contour image. Area calculating means for calculating the area, axis length calculating means for calculating the length of one of the major axis or the minor axis when elliptical approximation of the contour image is assumed, and the heart chamber area and the length of the one axis And volume calculation means for calculating a heart chamber volume when the heart chamber is approximated by an ellipsoid.

[0007] According to the above configuration, the volume calculation of the ellipsoid can be performed in consideration of the area in addition to the one axis while presuming the elliptical approximation of the heart chamber. Can be. If the ultrasound image has been processed into a contour image, the area of the heart chamber can be determined simply by counting the pixels or data inside it. Therefore, even with a complicated shape close to an ellipse, the volume can be calculated relatively accurately. Preferably, the heart chamber is the left ventricle, and means for calculating the ejection fraction from the left ventricular volume at the end diastole and the end systole of the heart is provided. Preferably, the one axis is a long axis. Using the long axis rather than the short axis facilitates setting and reduces errors. The setting of the major axis is performed manually or automatically.

By the way, the area S of the ellipse is as follows: S = πAB / 4 (2) where A is the length of the major axis and B is the length of the minor axis, so that B = 4S / ΠA (3) On the other hand, the volume V of the ellipsoid, since a ^{V = πAB 2/6 ··· (} 4), the equation ^{(3), V = 8πS 2 / 3πA ···} (5). Therefore, the volume of the ellipsoid can be represented by the length A of the major axis and the ellipse area S.

Here, as shown in FIG. 2, when the contour 102 of the left ventricle is approximated to an ellipse 100, for example, two end points on the long axis are directly specified by the user, or a line corresponding to the long axis is drawn. Two end points are specified by automatically performing edge detection on the line specified by the user, and in any case, the length A of the long axis is specified as a result, while the area inside the contour 102 is determined. S is obtained by a method such as counting the number of pixels. By substituting them into the above equation (5), the volume of the ellipsoid can be obtained. Incidentally, the volume can be similarly calculated by using the length B and the area S of the minor axis.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing a main part of the apparatus. Echo data is captured by transmission and reception of ultrasonic waves. A predetermined process is performed on the echo data, and the processed echo data is stored in a frame memory 12 provided in a digital scan converter (DSC) 10. Each echo data is sequentially output from the frame memory 12.

The ROI generator 16 is a circuit that generates an ROI (region of interest) that defines the outer edge of the contour extraction range. The center point and the size of the ROI are set manually, for example.

The gate circuit 14 is a circuit for extracting only data belonging to the ROI according to the address of the ROI generated by the ROI generator 16.

The contour extraction unit 18 is a means for extracting a contour image of the left ventricle, for example, by using various processes such as filtering, compression / decompression, and binarization. In the present embodiment, the binarized data is output from the contour extraction unit 18. The binarized data is input to the area calculator 20 and the length calculator 22.

The area calculating section 20 is a circuit for calculating the area of the contour, that is, the area of the left indoor space by counting the number of pixels in the contour, that is, the number of data.

The length calculating section 22 is a circuit for calculating the length of the major axis when the contour is approximated by an ellipse. The direction of the major axis is set by the user using the major axis specifying section 24. Of course, such designation of the major axis may be performed automatically, in which case the length is automatically recognized together with the designation of the major axis. Incidentally, although the approximate ellipse 100 for the outline 102 is shown in FIG. 2, the approximate ellipse 100 itself does not need to be particularly generated. In the present embodiment, as described above, the volume of the ellipsoid, that is, the volume of the left ventricle, can be easily calculated based on the area S and the length A or B of one of the major axis and the minor axis.

The volume calculating section 26 is a circuit for calculating the volume according to the above-mentioned equation (5). In this case, the volume calculation unit 2
Numeral 6 performs volume calculation for each frame.

The EF calculating section 30 is a circuit for calculating the ejection fraction EF, and specifically, is a circuit for executing the above-mentioned equation (1). In this case, the end-diastolic left ventricular volume EDV and the end-systolic left ventricular volume ESV are specified according to the R wave of the electrocardiographic signal. It should be noted that the maximum value and the minimum value of the volume are determined by using EDV and ES, respectively, without using such an electrocardiographic signal.
V. The calculated ejection ratio EF is numerically displayed on the display unit 32. Further, the calculated volume is displayed as a numerical value as needed, and further, a tomographic image and the like are displayed.

According to the above-described embodiment, since the volume calculation can be performed in consideration of the area within the actual contour as compared with the volume calculation using the long axis and the short axis, the calculation accuracy can be improved. There are advantages. As a result, highly accurate calculation of the ejection fraction EF becomes possible. In the above embodiment, the volume calculation is performed using the length A of the long axis, but the volume calculation may be performed using the length B of the short axis. However, if the long axis is used, there is an advantage that the setting can be facilitated and the calculation accuracy can be improved.

[0020]

As described above, according to the present invention,
The amount of calculation can be reduced to calculate the heart chamber volume with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 2 is a diagram showing a relationship between a contour and an approximate ellipse.

[Explanation of symbols]

12 frame memory, 14 gate circuit, 16 RO
I (region of interest) generator, 18 contour extraction unit, 20 area calculation unit, 22 length calculation unit, 24 long axis designation unit, 26
Volume calculation unit, 30 EF (ejection rate) calculation unit, 32 display unit.

Claims (3)

[Claims] 1. An outline image generating means for processing an ultrasonic image to generate an outline image of a heart chamber, an area calculating means for calculating a heart chamber area based on the outline image, and an ellipse approximation of the outline image. Axis length calculating means for calculating the length of one of the major axis or the minor axis in an assumed case; and the heart chamber volume when the heart chamber is approximated to an ellipsoid from the heart chamber area and the length of the one axis. An ultrasonic diagnostic apparatus, comprising: 2. The apparatus according to claim 1, wherein the heart chamber is a left ventricle, and means for calculating an ejection fraction from each left ventricular volume at the end diastole and the end systole of the heart is provided. Ultrasonic diagnostic equipment. 3. The ultrasonic diagnostic apparatus according to claim 1, wherein said one axis is a long axis.