JPS6272335A - Ultrasonic doppler diagnostic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention is capable of measuring a power spectrum in a living body using ultrasonic Doppler signals, and displaying temporal changes in this power spectrum in real time. This invention relates to an ultrasonic Doppler diagnostic device.

(B) Conventional techniques and their problems Conventionally, the ultrasonic pulsed Doppler method has been widely applied when diagnosing blood flow dynamics inside the heart. This ultrasound pulsed Doppler method utilizes the fact that when an ultrasound pulse is emitted into a living body, the frequency of the ultrasound echo reflected from inside the living body is slightly shifted from the frequency of the ultrasound pulse emitted by the Doppler signal. It measures the blood flow velocity in the living body.

By the way, conventionally, in order to observe blood flow dynamics, while looking at an ultrasound tomographic image, the radiation direction of the ultrasound beam is fixed toward the area where you want to measure the blood flow dynamics, and at the same time, the radiation direction of the ultrasound beam is fixed in the depth direction on the ultrasound beam. Set one sampling point. Then, a power spectrum is obtained from the Doppler signal obtained at this sampling point, and temporal changes in this power spectrum are displayed on a monitor or the like.

However, this method only allows you to see the temporal change in the power spectrum at one point in the diagnostic target area; when observing the power spectrum at other different areas,
The setting position of the sampling point must be changed each time. Therefore, if you want to observe temporal changes in blood flow velocity at multiple points in the depth direction on the ultrasound beam,
The above operation must be repeated many times, making the operation extremely complicated. Furthermore, since it is not possible to directly compare and observe the power spectra at multiple points, there have been problems such as difficulty in intuitively grasping differences in blood flow dynamics between different parts.

The present invention has been made in view of the above circumstances, and is capable of simultaneously displaying temporal changes in each power spectrum at a plurality of sampling points in the depth direction on an ultrasound beam in real time. Objective 1-1 is to enable direct comparison and observation of blood flow dynamics at multiple sampling points and to eliminate the complexity of conventional diagnostic operations.

(C) Means for Solving the Problems In order to achieve the object of [L], the present invention provides a system between the Doppler signal extraction circuit and the Fourier transform circuit in the depth direction on the ultrasonic beam. a setting means for setting a plurality of observation display points; a comparison means for comparing each sampling point with the observation display point set by the setting means for the Doppler signal; The ultrasonic Doppler diagnostic device includes a gate circuit that opens a gate to a signal.

(d) In order to display the temporal change in the action power spectrum, multiple observation and display points are selected from among the sampling points of the Doppler signal set in advance by a setting means corresponding to the depth direction on the ultrasound beam. Set it. Then, the comparison means successively compares each sampling point with the observation display point set by the setting means for the Doppler signal obtained by pulse-emitting the ultrasonic beam into the living body. When the sampling point coincides with the observation display point, a gate signal is applied from the comparing means to the gate circuit, so that the gate for the Doppler signal is released at this time.

Therefore, only the Doppler signals obtained at a plurality of preset observation display points among the sampling points are Fourier transformed and displayed as a power spectrum.

(e) Examples Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

FIG. 1 is a block diagram of the ultrasonic Doppler diagnostic apparatus of the present invention. In the figure, ■ indicates the entire ultrasound Doppler diagnostic device, 2 is a transducer that outputs an ultrasound echo signal obtained by emitting pulsed ultrasound beams into a living body, 4 is an oscillation circuit, and 4 is an oscillation circuit. A control circuit 24, which will be described later, creates an ultrasonic transmission repetition signal based on the signal from the ultrasonic transmitter/receiver circuit 6 to set the driving frequency of the transducer 2.

Reference numeral 6 denotes an ultrasonic wave transmitting/receiving circuit that outputs a driving pulse for driving the transducer 2 and also amplifies and detects an echo signal output from the transducer 2. Also, 8
10 is a Doppler signal extraction circuit that phase-detects the echo signal output from the ultrasonic wave transmitting/receiving circuit 2 and extracts a Doppler signal, and 10 is an A/D converter that digitizes the Doppler signal extracted by the Doppler signal extraction circuit 8. , 12 is a comb filter that removes unnecessary rutter components included in the Doppler signal digitized by the A/D converter 10; 14 is a buffer memory that temporarily stores the Doppler signal that has passed through the comb filter 12; 16; 18 is an FFT circuit that fast Fourier transforms the Doppler signal read out from the buffer memory 14, and a power spectrum calculation circuit 18 that calculates the power spectrum of blood flow velocity based on the Doppler signal that has been fast Fourier transformed by the PFT circuit 16. 20 is a display control circuit that converts the power spectrum data calculated by the power spectrum calculation circuit 18 into a display signal and outputs it; 22 is a monitor such as a CRT that displays an image of the output from the display control circuit 20; 24 is an ultrasonic wave Transmission/reception circuit 6, A/D
Converter 10. This is a control circuit that controls the operation of the buffer memory 14 and the like.

FIG. 2 is a block diagram showing details of the buffer memory 14. In the figure, 26 is a memory block that stores the Doppler signal that has passed through the comb filter 12, 28 is a write address counter that specifies the write address of the Doppler signal stored in this memory block 26, and 30
3 is a read address counter that specifies the read address of the Doppler signal stored in the memory block 26;
2 is a multiplexer that switches the outputs of both address counters 28 and 30; 34 is a multiplexer that selects a plurality of observation display points from among a plurality of Doppler signal sampling points in the depth direction on the ultrasonic beam (in this example, the depth of the memory block 26); This is a depth address data storage memory serving as a setting means for setting a depth address (corresponding to a predetermined read address in the direction). Further, 36 is an address counter for specifying the read address of the depth address data storage memory 34, and 38 is a comparison means for comparing each sampling point of the Doppler signal with the observation display point set in the depth address data storage memory 34. The comparator 40 is a gate circuit that releases the gate for the Doppler signal read out from the memory block 26 when the sampling point coincides with the observation display point.

Next, the operation of each part will be explained when the ultrasonic Doppler diagnostic apparatus I having the above configuration is applied to display, for example, temporal changes in the power spectrum of the heart.

When acquiring a Doppler signal, a driving pulse is output from the ultrasonic wave transmitting/receiving circuit 6 to the transducer 2 according to an instruction from the control circuit 24, and an ultrasonic pulse beam is repeatedly emitted from the transducer 2 into the living body. For example, as shown in Figure 3, if the ultrasound beam is emitted 128 times every 200 μs to obtain the power spectrum of one blood flow velocity, the period t is 25.6 m5e.
c, and therefore, a power spectrum of blood flow velocity is obtained every 25.6 m5ec. In this case, the radiation direction of the ultrasonic beam is fixed at a constant direction θ facing the diagnosis target region, as shown in FIG.

The ultrasonic beam emitted into the living body is reflected from various parts of the living body in the depth direction and is received again by the transducer 2. Then, since the transducer 2 outputs an echo signal corresponding to the received ultrasound echo, this echo signal is amplified and detected by the ultrasound transceiver circuit 6, and further phase-detected by the Doppler signal extraction circuit 8. A Doppler signal is extracted. The extracted Doppler signal is A/D
Each conversion converter l is considered.

The A/D converter IO digitizes the Doppler signal at regular intervals, for example, every 1.3 μs, corresponding to each sampling point in the depth direction on the ultrasound beam.

In this example, it is assumed that 128 sampling points are set in the depth direction. The Doppler signal digitized by the A/D converter 10 is sent to the next stage comb filter 12.
After the clutter components are removed, the signal is sent to the buffer memory 14. The Doppler signals are then sequentially written to the locations addressed by the write address counter 28 of the memory block 26.

Since the Doppler signal is Fourier-transformed every time period t of each unit time phase, the memory block 26 stores all the Doppler signals obtained within the time period of the unit time phase, as shown in FIG. . Therefore, the memory block 26 stores Doppler signals obtained each time an ultrasonic beam is radiated and has a resolution of 128 points in the depth direction (in the X direction in the figure) for the number of 128 irradiation points. Become.

As shown in FIG. 6, if you want to display, for example, four temporal changes in the power spectrum, four observation display points X3, x3, Set X4.

This is because the resolution in the depth direction of the memory block 26 is 128 points in this example, so each observation display point XI%
, x3, and x4 are set to, for example, addresses 20, 50, 80, and 120, and these addresses are stored in the depth address data storage memory 34 in advance. Keep the shellfish.

When the buffer memory 14 enters the read mode, the read address counter 30 specifies the read address of the memory block 26 . This addressing command for the read address counter 30 is also given to a comparator 38. The comparator 38 successively compares the address from the read address counter 30 and the address set in the depth address data storage memory 34, and the address of the read address counter 30 is compared with the address of the depth address data storage memory 34 (for example, the address set in the depth address data storage memory 34). In the example, the gate signal is output to the gate circuit 40 only when the address matches the address (20 in the example). This releases the gate for the Doppler signal read from the memory block 26. Since the gate signal from the comparator 38 is also applied to the address counter 36 and counts up the address counter 36, the next address (for example, address 50) is applied to the comparator 38 from the depth address data storage memory 34. Thus, memory block 2
Each time the address in the depth direction of No. 6 coincides with the 20th address, the 50th address, the 80th address, and the 120th address, respectively, 128 points of Doppler data corresponding to each address are sequentially read out in the Y direction in FIG.

Each of the 128 points of Doppler data read out in this way is sent to the next stage Fourier transform circuit 16, where 128 points of Doppler data are read out.
Fast Fourier transform is performed on 28 points of Doppler data. Subsequently, power spectrum calculation circuit 1
In step 8, a power spectrum is calculated based on the data of 128 points subjected to fast Fourier transform. The calculation result of the power spectrum J1 is displayed on the monitor 2 via the display control circuit 20.
2 is output. Therefore, as shown in FIG. 6, the monitor 22 displays each observation display point Xls X? set in the depth direction of the ultrasonic beam L. , ×3, and x4, temporal changes in four power spectra are displayed. In this display, the power spectrum is scrolled from right to left as time passes, and the power of the power spectrum corresponds to luminance. Note that in this embodiment, the setting means 34, the comparing means 38, and the gate circuit 40
is attached to the buffer memory 14, but it may be provided between the Doppler signal extraction circuit and the Fourier transform circuit.
For example, the A/D converter 10 or the comb filter 1
It is also possible to provide it attached to 2.

Furthermore, in this example, multiple observation display points are set on one ultrasound beam, but the radiation direction of the ultrasound beam is set in two directions, and multiple observation display points are set on each ultrasound beam. It is also possible to set points and display their respective power spectra at the same time.

(f) Signal As described above, according to the present invention, it is possible to simultaneously display temporal changes in the power spectrum at multiple sampling points in the depth direction within the living body, so the power spectra at multiple sampling points can be directly compared. This makes it possible to observe blood flow dynamics more accurately. Moreover, compared to conventional methods, there is no need for operations such as resetting the sampling points many times, so the complexity of diagnostic operations is eliminated and excellent signals are produced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the ultrasonic Doppler diagnostic device of the present invention, FIG. 2 is a block diagram showing details of the buffer memory,
FIG. 3 is an explanatory diagram showing the timing of collecting Doppler signals,
Figure 4 is an explanatory diagram showing the relationship between the radiation direction of the ultrasound beam and the observation display point, Figure 5 is an explanatory diagram showing the memory contents of the buffer memory, and Figure 6 is a diagram showing the temporal change in the power spectrum displayed on the monitor. FIG. 1. Ultrasonic Doppler diagnostic device, 8. Doppler signal extraction circuit, 14. Buffer memory, 16. Fourier transform circuit, 34. Depth address data storage memory (setting means)
, 38... comparator (comparison means), 40... gate circuit.

Claims (1)

[Claims] (1) A Doppler signal extraction circuit performs phase detection on the echo signal obtained by pulse-emitting an ultrasound beam into a living body to extract a Doppler signal, and a Fourier transform circuit performs a Fourier transform on the extracted Doppler signal to obtain a power spectrum. In an ultrasonic Doppler diagnostic device that calculates the temporal change in the power spectrum and displays an image on a monitor, a plurality of channels are connected between the Doppler signal extraction circuit and the Fourier transform circuit in the depth direction on the ultrasound beam. a setting means for setting an observation display point of the Doppler signal; a comparison means for comparing each sampling point of the Doppler signal with the observation display point set by the setting means; 1. An ultrasonic Doppler diagnostic device comprising: a gate circuit for releasing a gate for the ultrasonic Doppler diagnostic device.