JPH07303641A - Ultrasonic doppler diagnostic apparatus - Google Patents

Abstract

PURPOSE:To reduce a diagnosis time using an automatic tracing means for tracing a plurality of predetermined trace levels of Doppler waveforms individually one time and sampling a plurality of trace lines. CONSTITUTION:Ultrasonic beam waves transmitted or received by a probe 10 are controlled by a transmitting and receiving circuit 12. Cross demodulation is effected with respect to the ultrasonic beam waves in a cross demodulation circuit 14 connected to the transmitting and receiving circuit 12, to obtain a Doppler signal comprised of a signal of a real number section and a signal of an imaginary number section. The Doppler signal is applied to a velocity calculating circuit 18. A correlational signal is obtained by an autocorrelational circuit 16, and on the basis of the correlational signal, a kinetic velocity of a subject is determined as a Doppler deviational frequency. The Doppler deviational frequency is stored in each frame and is applied to a tracing section 30 having an automatic tracing circuit 34. In the automatic tracing circuit 34, the respective pixels of coordinates on the Doppler waveforms corresponding to a luminance level lower than the maximum luminance level by a predetermined amount are determined at one time of tracing, and the pixels are automatically, individually traced, and a plurality of the corresponding trace lines are sampled simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a function of an ultrasonic Doppler diagnostic apparatus, and more particularly, to a function of tracing a Doppler waveform representing a Doppler shift frequency of a subject over time.

[0002]

2. Description of the Related Art Generally, as an ultrasonic diagnostic apparatus for diagnosing a heart function, a blood vessel function, etc., it is utilized that a received signal obtained by scanning an ultrasonic beam undergoes Doppler shift by a moving body such as blood flow. Ultrasonic Doppler diagnostic devices are known.

In this ultrasonic Doppler diagnostic apparatus, a predetermined quadrature detection is performed on the obtained received signal to extract a Doppler signal, and further, autocorrelation processing and velocity calculation processing are performed on this Doppler signal. Finding the Doppler shift frequency.

Then, in order to observe the change with time of the obtained Doppler shift frequency, that is, the Doppler waveform (Doppler spectrum), the horizontal axis represents time t and the vertical axis represents the Doppler shift frequency ψd.
Further, a Doppler waveform in which the distribution of the Doppler shift frequency is represented by the level of brightness is displayed on the monitor, and a predetermined diagnosis is performed from the waveform.

For example, in so-called trace measurement for tracing a Doppler waveform, an operator traces a Doppler waveform displayed on a monitor using a trackball or the like and extracts a predetermined trace line. Then, based on this trace line, the average motion velocity of the moving body within a predetermined period and the blood vessel volume etc. are calculated by integrating the separately obtained cross-sectional area of the blood vessel, and the heart function and the blood vessel function are calculated from the obtained calculation results. Etc. can be diagnosed.

[0006]

Conventionally, there has been a problem that when an operator executes a Doppler waveform trace, the trace causes individual differences, the diagnostic results vary, and the reliability decreases. Therefore, in order to reduce this variation, it has been proposed to provide an ultrasonic diagnostic apparatus with an auto trace function that automatically traces a Doppler waveform.

However, in contrast to the manual trace process, in the auto trace process, the operator cannot know the state of the trace line until it is displayed on the monitor. That is, in auto trace processing,
If the operator sets the trace level (a predetermined brightness level based on the maximum brightness level of the Doppler waveform) in advance,
The coordinates on the Doppler waveform corresponding to this trace level are determined and tracing is performed.

Therefore, if the set brightness level is not optimum, the intended trace line cannot be obtained.
Then, in this case, the operator sets the trace level again and until the optimum trace line is obtained,
It was necessary to erase the previous processing result and repeat the above trace processing.

As described above, by adopting the auto-trace processing, in order to obtain the optimum trace line, the diagnosis time may be longer than that of the manual trace, and the diagnosis time required for the ultrasonic diagnosis may be shortened. There was a problem that it would be against shortening.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an ultrasonic Doppler diagnostic apparatus capable of obtaining an optimum trace line in a short time without repeating the trace processing. .

[0011]

In order to achieve the above object, the ultrasonic Doppler diagnostic apparatus according to the present invention has the following features.

[0012] In an ultrasonic Doppler diagnostic apparatus for transmitting and receiving an ultrasonic beam to and from a subject and extracting a Doppler waveform representing a temporal change of the Doppler shift frequency based on the received wave, a plurality of predetermined trace levels of the Doppler waveform It is characterized in that it has an auto trace means for extracting a plurality of trace lines by auto tracing each of them at a time.

The plurality of trace levels are predetermined brightness levels of the Doppler waveform and are brightness levels lower than the maximum brightness level of the Doppler waveform by a predetermined amount.

It is characterized in that it has a storage means for storing a plurality of the extracted trace lines, and an arbitrary trace line is called from the storage means and displayed on a monitor according to an operator's selection.

[0015]

According to the ultrasonic Doppler diagnostic apparatus according to the present invention, a plurality of trace lines corresponding to a plurality of trace levels are extracted by one trace processing regardless of the trace level selected by the operator.

Therefore, even if, for example, the trace line selected by the operator and displayed on the monitor is not the optimum one of the extracted trace lines, the trace lines corresponding to other trace levels are Since it has already been extracted, it is possible to display that trace line immediately by simply reselecting another trace level.

As described above, it is not necessary to repeat the trace processing for obtaining the optimum trace line, particularly the determination of the trace coordinates, and the diagnosis time can be shortened.

[0018]

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

FIG. 1 is a schematic block diagram showing an ultrasonic Doppler diagnostic apparatus according to an embodiment of the present invention.

The transmission / reception circuit 12 is a circuit for controlling transmission / reception of the ultrasonic beam of the probe 10. Quadrature detection circuit 14
Is a detection unit that is connected to the transmission / reception circuit 12 and performs quadrature detection by multiplying a received signal by a predetermined reference wave.

A Doppler signal composed of two signals of a real number part and an imaginary number part obtained by quadrature detection is a high-speed (high frequency band) Doppler signal by a predetermined high-pass filter (not shown). Only is extracted. If the subject is a blood vessel, the Doppler signal extracted by this high-pass filter is a signal related to blood flow.
If this filter is a low-pass filter, a low-speed Doppler signal, for example, a signal related to living tissue such as myocardium can be extracted.

The auto-correlation circuit 16 is a circuit for performing a known correlation calculation process on the extracted Doppler signal in the high frequency band to obtain an auto-correlation. A speed calculation circuit 18 is connected to calculate the motion speed of the subject as a Doppler shift frequency based on the calculated correlation signal.

A memory 20 controlled by a control circuit (CPU) 24 is connected to the speed calculation circuit 18, and the calculated Doppler shift frequency is stored for each frame and output to the trace processing unit 30. To do.

On the other hand, the input unit 22 is a keyboard, a trackball, or the like for the operator to set predetermined conditions for measurement and diagnosis and a display state on the monitor 42. Further, the input unit 22 instructs to set or change the brightness level of the trace line displayed on the monitor 42, that is, a brightness level lower than the maximum brightness level of the Doppler waveform by a predetermined amount.

The various conditions set by the input unit 22 are CP
It is output to the graphic display circuit 26 via U24. Then, the graphic display circuit 26 includes the CPU 24.
Is a circuit which is controlled by, and supplies information such as line data, scale data, a character, and a trace level of a Doppler waveform to the trace processing unit 30 according to various set conditions.

The trace processing unit 30 is composed of a noise level detection circuit 32 for detecting a reference noise level and an auto trace circuit 34 for auto tracing a Doppler waveform.

Here, the noise level detection circuit 32 is a circuit for detecting the reference noise level from the luminance distribution of each pixel in which the existence probability of Doppler waveform data is low, for example, the upper edge portion and the lower edge portion of the image area. However, the circuit is not always necessary in this embodiment. However, since the ultrasonic image generally has a lot of noise, the noise level detection circuit 3 described above is used.
If the reference noise level 2 is provided and the Doppler waveform is auto-traced with reference to the reference noise level 2, it is possible to improve the accuracy of the trace and the smoothness of the extracted trace line.

The auto-trace circuit 34 is lower than the maximum brightness level by a predetermined amount when the maximum brightness level indicating that the distribution of the specific Doppler shift frequency in the Doppler waveform is the largest, that is, the power is the reference. Pixel at each coordinate on the Doppler waveform corresponding to the brightness level is 1
Determined during each trace processing. Then, it is a circuit that auto-traces each of these pixels and simultaneously extracts a plurality of corresponding trace lines.

The plurality of extracted trace lines are temporarily recorded in a recording unit (not shown) of the auto trace circuit 34, and the information of the trace line corresponding to the trace level selected by the operator via the input unit 22 is recorded in this recording unit. And is displayed on the monitor 42 via the DSC (digital scan converter) 40.

On the output side of the trace processor 30,
Similarly, an average speed calculation circuit (not shown) is connected.
This average velocity calculation circuit performs a predetermined calculation process based on the extracted trace line information to obtain the average movement velocity of the moving body within a predetermined period, the blood flow in the blood vessel, the peak ratio of the trace line, etc. . And
The information such as the obtained average motion velocity is combined with the trace line information and the like, and is displayed on the monitor 42 via the DSC 40.

Next, a data processing procedure in the auto trace circuit 34, which is a feature of this embodiment, will be described with reference to FIGS. 1 and 2. Here, FIG. 2 shows the procedure of the auto trace in the auto trace circuit 34.

In order to reduce the influence of noise in the trace processing, when the noise level detection circuit 32 is provided as required as described above, first, the noise level detection circuit 32 detects the baseline position of the Doppler waveform. A data sample area for detecting the reference noise level is obtained based on (position indicating movement velocity 0). Then, the reference noise level is detected in this data sample area and output to the auto trace circuit 34.

The auto trace circuit 34 first takes in one frame of ultrasonic image data including the Doppler waveform from the memory 20 (S1).

Then, the scale condition, character data, etc. set by the operator operating the input unit 22 are supplied from the graphic display circuit 26 to the trace processing unit 30, and correspondingly, predetermined image processing is performed on the Doppler waveform. Is performed (S2). Further, in this image processing, known moving average processing for smoothing the Doppler waveform is also performed. Next, the result of this image processing is freeze-displayed (still-image display) as an ultrasonic image on the monitor 42.

The operator operates the input unit 22 to select the trace level for the freeze-displayed ultrasonic image (S3), and further selects the trace range (S).
4). Either the trace level or the trace range may be selected first. In addition, when selecting the trace range, the conditions such as the trace direction may be selected at the same time.

Here, the trace level, that is, the plurality of predetermined luminance levels of the Doppler waveform, specifically means, as shown in FIG. 3, the highest luminance level of the Doppler waveform (the distribution of the Doppler shift frequency is the largest). , And a luminance level which means that the power of the frequency is large), which is lower than the luminance level by a predetermined amount and is statistically required to be a plurality of minimum luminance levels. For example, if the maximum brightness level is 0 dB, the maximum brightness level is 0 dB, -3d
The brightness levels are lower by B, -6 dB, -9 dB, -12 dB, and -18 dB. However, the interval and type of the brightness level are not limited to this, and are variable values depending on the diagnostic condition and the device. Furthermore, this brightness level can be arbitrarily changed by the operator by operating the input unit 22 according to the conditions.

Next, each coordinate (each pixel on the monitor 42) corresponding to a plurality of predetermined brightness levels of the Doppler waveform is determined. Then, each of them is automatically traced at a time to extract a plurality of corresponding trace lines (S5). The above predetermined brightness levels: 0 dB, -3 dB, -6 dB,-
The results of tracing the coordinates on the Doppler waveform corresponding to 9 dB, -12 dB, and -18 dB are shown in FIG. 4 with the vertical axis representing the Doppler shift frequency f (v) and the horizontal axis representing the time t.

The information of each trace line extracted as described above is stored in a storage unit (not shown) in the auto trace circuit 34. However, this storage unit may be provided outside the auto trace circuit 34.

Next, the trace line corresponding to the trace level selected by the operator in step 3 (S3) is
It is synthesized with the Doppler waveform and displayed on the monitor 42 (S
6). For example, when the selected trace level is -9 dB, the monitor 42 displays the trace line shown by the solid line in FIG.

The operator confirms the displayed trace line (S7). If the trace line is the optimum one, the trace process is terminated. If it is not the optimum one, the input section 22 is operated to trace level. Change is designated, that is, another trace level is selected (S8).
Then, the information of the trace line corresponding to the newly selected trace level is read from the storage unit in the auto trace circuit 34, and this is displayed on the monitor 42 vertically (S9).

The above processing is repeated, and when an optimum trace line is obtained, the trace processing ends.

Then, the obtained trace line information is output to the average velocity calculation circuit, where the average velocity of the moving body, the blood flow rate in the blood vessel, the ratio of a plurality of peaks of the trace line, etc. are obtained, and these calculation results are obtained. Is displayed on the monitor 42 via the DSC 40, and a diagnosis of a heart function, a blood vessel function or the like is performed.

As described above, in the present embodiment, regardless of the trace level selected by the operator, the pixels at the respective coordinates on the Doppler waveform corresponding to a plurality of predetermined trace levels are auto-traced at one time, and the corresponding values are obtained. We decided to extract multiple trace lines.

Therefore, even if the trace level is changed, another trace line can be displayed by simply reading the information of the corresponding trace line from the storage unit, and the trace process (especially the coordinate determination process) can be performed each time the trace level is changed. It is possible to significantly shorten the diagnosis time as compared with the conventional method which has been repeated.

In this embodiment, only the trace line corresponding to the selected trace level is monitored 42.
However, as shown in FIG. 4, the trace line of the selected level may be displayed as a solid line, and the other trace lines may be displayed as a dotted line at the same time. By displaying a plurality of trace lines at the same time, it becomes extremely easy to select the optimum trace level, and it becomes possible to contribute to the reduction of the diagnosis time.

Further, in the present embodiment, the trace lines are sequentially displayed on the monitor 42 from the determined coordinates so that the operator can observe the trace lines on the monitor 42 at any time. However, the trace lines may be collectively displayed after the completion of all the trace processing for the designated range. However, displaying the trace lines in sequence has the effects that the operator does not feel uncomfortable and that the determination that the selected trace line is not optimal can be executed in a shorter time.

[0047]

As described above, according to the ultrasonic Doppler diagnostic apparatus of the present invention, a plurality of trace levels corresponding to a plurality of trace levels can be obtained in one trace processing regardless of the trace level selected by the operator. Extract the trace line of.

Accordingly, even if the trace line selected by the operator and displayed on the monitor is not the intended one, the corresponding trace line can be immediately displayed by selecting another trace level. Therefore,
It is not necessary to repeat the trace processing to obtain the optimum trace line, and the diagnosis time can be shortened.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an ultrasonic Doppler diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an auto-trace procedure in an auto-trace circuit 34 of FIG.

FIG. 3 is a diagram showing a relationship between Doppler shift frequency and luminance.

FIG. 4 is a diagram showing extracted trace lines.

[Explanation of symbols]

 16 autocorrelation circuit 18 speed calculation circuit 20 memory 30 trace processing unit 34 auto trace circuit 42 monitor

Claims (3)

[Claims] 1. An ultrasonic Doppler diagnostic apparatus that transmits and receives an ultrasonic beam to and from a subject and extracts a Doppler waveform that represents a temporal change in a Doppler shift frequency based on the received wave. An ultrasonic Doppler diagnostic apparatus having an auto-trace means for automatically tracing each trace level at a time to extract a plurality of trace lines. 2. The ultrasonic Doppler diagnostic apparatus according to claim 1, wherein the plurality of trace levels are predetermined brightness levels of the Doppler waveform, and the brightness is lower by a predetermined amount than the maximum brightness level in the Doppler waveform. An ultrasonic Doppler diagnostic device characterized by a level. 3. The ultrasonic Doppler diagnostic apparatus according to claim 1, further comprising a storage unit that stores the plurality of extracted trace lines, and an arbitrary trace according to an operator's selection. An ultrasonic Doppler diagnostic apparatus wherein a line is called from the storage means and displayed on a monitor.