JPH0636798B2 - Ultrasonic blood flow imaging device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an ultrasonic blood flow imaging apparatus that two-dimensionally color-displays blood flow information in a subject.

[Technical Background of the Invention and Problems] In the field of performing ultrasonic diagnosis of a circulatory organ of a subject, an ultrasonic blood flow imaging apparatus that two-dimensionally color-displays blood flow information of the circulatory organ and the like has been conventionally used. Exists.

FIG. 4 shows an example of a display in such an apparatus. A tomographic image 1 of a subject is displayed in black and white, and color information indicating a change in the velocity of blood flow 2 is displayed in the tomographic image 1. It Further, the color bar 3 is simultaneously displayed on the same screen, and the blood flow information can be recognized by comparing the color of the color bar 3 with the color of the blood flow 2. Normally, the color bar 3 shows a change in blood flow velocity V due to a color change in the horizontal direction (blue-red), and a change in dispersion degree (disorder of average velocity) σ ² due to a color change in the vertical direction.

However, with such a display, it is extremely difficult to accurately confirm a region in the blood flow 2 where the flow is equal (hereinafter, referred to as “equal flow velocity region”). There is a problem in determining the degree.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ultrasonic blood flow imaging apparatus capable of accurately and easily confirming a constant flow velocity region of blood flow. To provide.

[Summary of the Invention] The summary of the present invention for achieving the above object is to calculate an average velocity of blood flow from an echo component from an object of an ultrasonic wave transmitted toward the object, and calculate the calculated blood flow. In the ultrasonic blood flow imaging device that displays the average velocity in color,
A speed input unit capable of inputting a desired blood flow speed, and a color corresponding to the blood flow speed input by this speed input unit are converted into colors that can be distinguished from adjacent colors on the display screen, thereby displaying It is characterized by comprising a color conversion unit capable of setting a constant flow velocity line of blood flow on a screen.

[Examples of the Invention] Hereinafter, the present invention will be specifically described with reference to Examples.

FIG. 1 is a block diagram showing the main part of an ultrasonic blood flow imaging apparatus which is an embodiment of the present invention. FIG. 4 shows an ultrasonic wave transmission / reception unit, which is an ultrasonic probe 5 that transmits and receives ultrasonic waves, a transmission unit 6 that outputs a transmission pulse for driving the ultrasonic probe 5, and an ultrasonic probe that detects the ultrasonic waves. And receiving means 7 for receiving the echo signal. Further, 8 is a phase detector for phase-detecting the echo signal received by the receiving means 7, 9 is a low-pass filter for removing unnecessary frequency components from the output of the phase detector 8, and 10 is an output of the low-pass filter 9. A / D (Analog / Digital)
The conversion unit 11 is an MTI filter that subtracts an echo signal from a region that moves very slowly (for example, the heart wall),
Reference numeral 12 denotes an average velocity calculation unit for calculating an average velocity of blood flow from the output of the MTI filter 11, and reference numeral 13 denotes a DS mainly constituted by a memory for storing the output of the average velocity calculation unit 12.
A C (digital scan converter), 14 is a color conversion unit for converting the output of the DSC 13 into a color signal, and a color conversion unit for converting the color at the blood flow velocity input by a velocity input unit 16 described later into white, and 15 is the color conversion unit. A color conversion unit for converting the color at the blood flow velocity input by the color conversion unit 16 into white, and 15 is the color conversion unit 1.
4 is a display unit that displays blood flow information based on the color signals output from the display device 4. A tomographic image created by a tomographic image created by a tomographic image processing unit (not shown) is also displayed on the display unit.

The velocity input unit 16 is for inputting the blood flow velocity set to white in the color conversion unit 14, and is set by the velocity setting unit 17 that sets the blood flow velocity and the velocity setting unit 17. And a variable resistor 18 for selectively varying the blood flow velocity.

Next, the operation of the embodiment apparatus configured as described above will be described.

The ultrasonic probe 5 is excited by the transmission pulse output from the transmission unit 6, and the ultrasonic pulse is transmitted toward the subject. The ultrasonic echo from the subject is received by the ultrasonic probe 5 and received by the receiving unit 7. The echo signal received by the receiving unit 7 is phase-detected by the phase detecting unit 8, input to the A / D converter 10 via the low-pass filter 9, converted into a digital signal, and then averaged via the MTI filter 11. It is input to the speed calculator 12. Then, the average speed calculation unit 12 causes the M
The average velocity of blood flow is calculated from the output of the TI filter 11. As is well known, the average velocity of blood flow can be obtained from the calculation result of the average value of the shift frequency of Doppler, for example, by the autocorrelation method. The average value d of the Doppler shift frequency can be calculated by the following equation.

d = (fr / 2π) · tan ⁻¹ {Σ (X _i Y _{i + 1} −Y _i X _{i + 1} )} / {Σ (X _i X _{i + 1} + Y _i X _{i + 1} )} ... (1 ) Here, fr is the ultrasonic pulse repetition frequency, and X and Y are phase detection outputs that are 90 ° out of phase with each other. Since the average value d of the Doppler shift frequency and the average velocity of blood flow have the following relationship, the average velocity of blood flow can be calculated from this relationship.

d = {2 (cos θ) f ₀ } / c (2) where c is the speed of sound 1500 m / s.

Then, the calculated average blood flow velocity is input to the color conversion unit 14 via the DSC 13 and color-converted.

When a desired blood flow velocity is input through the velocity input unit 16 by a doctor or the like, the color conversion unit 14 converts the color at the blood flow velocity into white. That is, as shown in FIG. 2, assuming that the average velocity from the DSC 13 can vary within a range of ± 15 around O, the average velocity of blood flow is red around black or red depending on this variation. Although the color is changed to blue and has a different brightness, when the blood flow velocity of +8 is set by the velocity input unit 16, the color conversion unit 14 changes the entire region at the average blood velocity +8. It will be converted to white. The reason for converting to white is to clearly distinguish it from the original colors (red and blue) of the average velocity of blood flow.
Therefore, a color other than white may be converted as long as it can be distinguished from the adjacent colors on the display screen.

The blood flow information color-converted in this way is displayed on the display unit 15.
Is displayed in color. FIG. 3 shows an example of the display of the display unit 15, in which the isokinetic flow line 19 is displayed in white on the blood flow 2, and the blood having the isokinetic flow line 19 set in the color bar 3 is also displayed. Corresponding flow velocity markers 20 are displayed in white corresponding to the flow velocity. The iso-velocity line 19 indicates the iso-velocity region of the blood flow.

Therefore, the doctor or the like can see the uniform flow rate line 19 displayed on the display unit 15.
It is possible to confirm the more uniform flow velocity area accurately and easily.
By setting the uniform flow velocity line 19 to the abnormal blood flow velocity, it becomes possible to intuitively determine the severity of the sample from the area of the abnormal blood flow site.

Although one embodiment of the present invention has been described above, it is needless to say that the present invention is not limited to the above embodiment and can be appropriately modified within the scope of the gist of the present invention.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide an ultrasonic blood flow imaging apparatus capable of accurately and easily confirming a constant flow velocity region of blood flow information.

[Brief description of drawings]

FIG. 1 is a block diagram showing the main part of an ultrasonic blood flow imaging apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory view for explaining the operation of a color conversion unit in the apparatus of this embodiment,
FIG. 3 is an explanatory diagram showing an example of a display in the device of this embodiment, and FIG. 4 is an explanatory diagram showing an example of a display in the conventional device. 14 ... Color conversion unit, 16 ... Speed input unit.

Claims (1)

[Claims] 1. An average velocity of blood flow is calculated from an echo component from an object of ultrasonic waves transmitted toward the object,
In an ultrasonic blood flow imaging apparatus that displays the calculated average blood velocity in color, a velocity input unit that can input a desired blood velocity and a color corresponding to the blood velocity input by this velocity input unit are displayed. An ultrasonic blood flow imaging apparatus comprising: a color conversion unit capable of setting a constant flow rate line of a blood flow on a display screen by converting the color into a color distinguishable from colors adjacent to each other on the screen.