JPS6274344A - Ultrasonic 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 [Technical Field of the Invention 1] The present invention relates to a medical ultrasonic diagnostic apparatus, and particularly to a medical ultrasonic diagnostic apparatus that uses ultrasonic echo information to generate a two-dimensional blood flow image using the cross-sectional R& or the Doppler effect of ultrasonic waves. This article relates to ultrasonic diagnostic equipment for diagnosis.

[Technical background of the invention and its problems 1 To explain the principle of obtaining blood flow information from ultrasound echoes with reference to FIGS. 4 and 5, ultrasonic waves are A pulse is transmitted, and a Doppler shift signal is detected by a phase detector 3 from echo information received by a wave transmitting/receiving circuit 2. In this case, the detected Doppler deviation 13@
is captured at each of, for example, 256 sample points SP provided in the direction of the ultrasound beam. In this way, the number point $
1-] is calculated by the blood flow calculation unit 4, and the obtained blood flow signal is transmitted to the DSC 5 and the display unit 6, so that a +ru flow image in the forward direction is displayed on the display unit 6. Ru. Next, the ultrasonic beam is moved in direction B and the same operation is performed. In this way, the display range is scanned in real time, and by detecting blood flow information and displaying blood flow signals in each direction, two-dimensional Blood flow images can be viewed in real time.

In the described operation, in order to obtain blood flow information from ultrasound echoes, it is necessary to separate ultrasound echoes from stationary objects such as tissues and ultrasound echoes from moving objects such as blood cells. This is done by using a filter to filter out objects with high Doppler shift frequencies (ultrasonic waves) from fast-moving objects. and,
To display secondary blood flow information, as described above, transmit ultrasound several times in one direction, for example, in the direction, and use the ultrasound echoes from multiple depth points in that direction] − needs to be processed simultaneously. This is essential in order to shorten the time required to compose one image and to make the image a real-time image.

Incidentally, although a digital filter is used as the filter, the number of points that can be echo-processed in one ultrasonic scanning direction is limited by the time required to process one point. If this 98 instant time is sufficiently short and the number of points in one direction is sufficiently large compared to the resolution of the display system, there may be no inconvenience, or in reality, if the processing content such as the order of the filter becomes advanced. The processing time becomes longer, and the number of points required to satisfy the resolution of the display system cannot be processed, resulting in a rough image. Therefore, there is a trade-off between simplifying the processing content and making the image rougher.

Now, the filtering and correlation coefficient calculations so far are as follows:
The data input order or the receiving order of the supersontal echoes as shown in Figure 6 are exactly the same, but the input order is different from the processing order, so the internal memory 7 is the same as shown in Figure 7. The values of internal registers are output one after another so that processing can be performed on depth data.

I needed to get used to it. Therefore, due to increased processing time due to memory access time and the fact that the data flow is not unidirectional, channel multiplexing is necessary due to the inability to perform pipeline processing, and the processing time cannot be shortened. It had

[Objective of the Invention 1] The present invention has been made in view of the above-mentioned circumstances, and provides an ultrasonic diagnostic apparatus that is capable of processing advanced processing contents in a relatively short period of time and is capable of preserving image fineness. The purpose is to

[Summary of the Invention] The outline of the present invention for quickly accomplishing the above object is to scan a subject with a transducer that transmits ultrasonic waves based on an output signal from an oscillator, and to detect images from within the subject. The ultrasound echo information is transmitted through a detector into an ultrasound diagnostic device that displays a tomographic image or a blood flow image of the subject, and the ultrasound echoes are sampled by 1 linearity with respect to the ultrasound pulse. and an AD converter that converts it into a digital signal, and this △D! a buffer memory for temporarily storing the converted data; a digital filter for removing low Doppler shift frequencies from the data from the buffer memory;
A frequency analysis circuit that calculates the autocorrelation coefficient of the output signal of this digital filter and calculates the frequency information for the Doppler shift 1 to frequency, and outputs the digital data from the buffer 7 memory 1 corresponds to the same depth. Memo that can be rearranged so that it can be output as data in chronological order i)
and a continuous control circuit.

[Embodiment 1 of the invention Embodiments of the present invention will be described below with reference to the accompanying drawings.

The principle for obtaining blood flow information from ultrasound echoes according to the present invention is the same as that shown in FIGS. 4 and 5, so the explanation will be omitted.
First, to explain the principle of rearranging digital data using FIG. 1, the order of digital data input to the 7 buffers, ie, 1A, 1B, IC, 1D shown in FIG.
...] K, 2 A.

2B, 2C, 2D...2K, 3A, 38.3C, 3D
・3 K, ・, nA, nB, nC, nD-nK 11
Figure 1 shows the order of input data when filtering the 11 + order and calculating the autocorrelation coefficient.
A, 2A, 3A, 4A-n to 1B, 2[”'3.3
B, 4B, -nF3.10.2G, 3C, I+ C-n
C1..., 1, 2, 3, 4 are rearranged in the order of -nK.

Next, the configuration of the arithmetic unit using the above principle will be explained.

In FIG. 2, ] 1 is an AD converter that samples ultrasonic echoes generated in response to ultrasonic pulses and converts them into digital signals; 12 is a buffer memory that temporarily stores the AD-converted data; A digital filter that removes low Doppler shift frequencies from the data from the buffer memory 12; 14 is a frequency analysis circuit that calculates the autocorrelation coefficient of the output signal of the digital filter 13 and obtains a frequency with respect to the Doppler shift frequency;
Reference numeral 15 is a memory read control circuit which rearranges the digital data from the buffer memory 12 so that the data corresponding to the same depth can be output in time series as shown in FIG.

Next, the operation of the above device will be explained. As explained in FIGS. 4 and 5, the ultrasonic pulse is generated from the probe 1, and the output signal from the phase detector 3 is converted into a digital signal by the AD converter 11 shown in FIG. is temporarily stored. Next, data is stored in the buffer memory 12 by repeating ultrasonic wave transmission several times, and the data in the buffer memory 12 is read out in order to analyze the Doppler shift during this period. In this case, the data in the buffer 7 memory 12 is rearranged as in the first time so that the data at the same depth is output in chronological order, unlike the order in which it was inserted, and is then rearranged according to the address from the memory successive control circuit 15. be transferred. In this way, there is no need for time-division V-channel multiplexing of time-series data at the same point as in the case where the sampling order is the same as that of the channel multiplexer 11. However, initialization is required when inputting data for the first time.

The data arranged in chronological order is sequentially sent to the digital filter 13 and the frequency analysis circuit 14, and the low frequency components are removed, the autocorrelation coefficient is calculated, and the frequency information based on the output thereof is analyzed in a single channel. data is processed and sent to the display system for display.

Next, regarding the difference between channel multiplexing processing and single channel processing, we will explain the difference between channel multiplexing processing and single channel processing using the second-order recursi
A detailed explanation will be given by taking the case of a ve digital filter as an example. The filter 12 receives the input signal and the first filter as shown in FIG.
．． It consists of a multiplier/adder 18 of a second internal register 16. The second registers 16 and 17 record intermediate results when the time series data at that point is input.

By the way, in the case of channel multiplexing, data is not input in chronological order, so the data that comes in after filtering at a certain point becomes input data at a different point, so the value of this register is changed as shown in Figure 7. It is necessary to temporarily store the data in another memory 7 and read it again when the corresponding data is panned at the time of receiving the next transmitted wave pulse. However, in the case of single channel filtering, this register value can be used as it is to control the output corresponding to the next input data, so the memory 7 for temporarily storing the register value is unnecessary and Since no time is required for occupying or reading the memory 7, high-speed processing is possible.

Incidentally, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, the present invention may be applied when image processing is performed using echo signals to reproduce and display a tomographic image.

[Effects of the Invention] In the present invention, the output order of digital data from the buffer 7 memory is rearranged by the memory succession control circuit so that the output order of digital data can be outputted in time series as data corresponding to the same depth. Even in the case of advanced processing such as digital filtering, a filtering cycle time can be achieved using a simple circuit in a processing time that allows the fineness of the image to be maintained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the principle of the present invention, Fig. 2 is a block diagram showing an embodiment of the arithmetic unit of the invention, Fig. 3 is a block diagram of a secondary digital filter, and Fig. 4 is a two-dimensional blood flow diagram. [Schematic explanatory diagram showing the principle of imaging; Fig. 5 is a block diagram of a general ultrasound diagnostic device; Fig. 6 is an explanatory diagram of the order of data input to the conventional buffer memory and the order of filter processing; Fig. 7 is a diagram showing the order of data input to the conventional buffer memory and the order of filter processing. FIG. 2 is an explanatory diagram of a channel multi-type filter. 11... AD converter, 12... Buffer memory, 13... Digital filter, 14... Frequency analysis circuit, 15... Memory read control circuit. Agent Patent attorney Nori Chika Ken Canshu Dai Ko Norifu □□ Rureto 7 L-to Z L-to 5--
1A, old, IC, ID ---IK, 2A2B, 2C,
−−−6 Figure 111 −−− −Rate π

Claims (1)

[Claims] A transducer that transmits ultrasonic waves based on the output signal from the oscillator scans the subject, and a tomographic image of the subject is obtained from the echo information obtained from the ultrasonic echoes from inside the subject via a detector. Or in an ultrasound diagnostic device that displays blood flow images,
An AD converter samples ultrasonic echoes obtained in response to ultrasonic pulses and converts them into digital signals, a buffer memory temporarily stores this AD-converted data, and a Doppler shift frequency is calculated from the data from this buffer memory. A digital filter that removes low frequencies, a frequency analysis circuit that calculates the autocorrelation coefficient of the output signal of this digital filter and obtains frequency information about the Doppler shift frequency, and the output order of the digital data from the buffer memory is at the same depth. What is claimed is: 1. An ultrasonic diagnostic apparatus comprising: a memory read control circuit that rearranges data so as to output data in chronological order as corresponding data.