JPH11104135A - Ultrasonic diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to display the time images in M-mode, Doppler spectrum mode, etc., and a diagram of calculation results on a same screen, by displaying a time course of ultrasonic information on an arbitrary line in a subject and a time diagram of measured values measured from the ultrasonic information. SOLUTION: Echo signal formed in a transceiver circuit 13 are transmitted to a mixer 40 to be mixed with reference signals from a reference signal generating part 20 and phase-shifted reference signals with 90 deg. shifted phase. The mixed signals are passed through an LPF 43 and signals in the region of interest are cut out by a range gate circuit 60 from doppler signals with doppler deviated frequency and transmitted to a sample hold circuit 61. Next, outputted signals of the circuit 61 are transmitted through a BPF 63 and an A/D convertor 65 to a high speed Foulier transformer 67 and frequency-analyzed to obtain a vascular flow frequency spectrum. The vascular flow spectrum is arranged parallel along the time coordinate at a DSC 30 and displayed as an image in doppler spectrum mode on a display 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an M-mode or MDF
By displaying a one-dimensional tissue image or blood flow image on an arbitrary line inside the subject as in the mode, or by arranging the blood flow spectrum in the sample volume along the time axis as in the spectrum Doppler mode. Also, the present invention relates to an ultrasonic diagnostic apparatus which provides a time-dependent change in a tissue or a blood flow in an easily understandable manner.

[0002]

2. Description of the Related Art There are various medical applications of ultrasonic waves, and the mainstream is an ultrasonic diagnostic apparatus for tomographic images of soft tissues of a living body using an ultrasonic pulse reflection method. This ultrasonic diagnostic apparatus is a non-invasive examination method and displays a tomographic image of a tissue. It has unique features such as display capability, small and inexpensive device, high safety without exposure to X-rays, and the ability to perform blood flow imaging by the ultrasonic Doppler method.

[0003] Therefore, it is widely used in the heart, abdomen, mammary gland, urology, obstetrics and gynecology, and the like. In particular, with the simple operation of simply assigning the ultrasound probe from the body surface, the state of the heart beat and the movement of the fetus can be obtained in real time display,
In addition, the safety is high, so that the inspection can be repeated, and the inspection while moving to the bedside can be easily performed.

The above-described one-dimensional tissue image and blood flow image on an arbitrary line inside the subject, and the blood flow spectrum of the sample volume are arranged and displayed along the time axis to display the time of the tissue and blood flow. In the M mode, MDF mode, and spectrum Doppler mode that can provide the change in detail, taking advantage of each characteristic, the left ventricular end diastolic volume, the left ventricular end systolic volume, the pressure gradient, the pressure half time,
Speed slope (acceleration measurement), stroke volume, cardiac output,
Various measurements such as RI (Resistance Index) and PI (Pulsatility Index) are possible. Conventionally, such various counting results can be displayed numerically together with the image, and the change over time can be displayed in a graph.

A time graph of such a counting result is usually displayed vertically above and below the image in the M mode or the Doppler spectrum mode so as to match the time scale. However, the images in the M mode and the Doppler spectrum mode are displayed while scrolling several heartbeats, and are adjusted to the time width of several seconds such as the several heartbeats in the M mode and the Doppler spectrum mode. If, for example, an attempt is made to display a graph of the RI, one value is obtained for this RI per heartbeat, the graph is very discrete, and it is not enough to catch the change over time.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of displaying a graph of a counting result on the same screen as a time image such as an M mode or a Doppler spectrum mode so that a change with time can be easily grasped. It is in.

[0007]

According to the present invention, a time graph of ultrasonic information on an arbitrary line in a subject and a time graph of measured values measured based on the ultrasonic information are displayed at different times. Since the value is displayed in the width, it is easy to catch a change with time, for example, even with a count value such as RI in which only one value is obtained in one heartbeat.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic diagnostic apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of an ultrasonic diagnostic apparatus according to the present embodiment. In the present embodiment, a one-dimensional tissue image (B-mode image) or blood flow image (color flow mapping image) on an arbitrary line inside the subject, or a blood flow spectrum relating to a sample volume at an arbitrary depth on the line. Are arranged along the time axis, and the M mode, the MDF mode, and the spectrum Doppler mode, which can provide time-dependent changes in tissue and blood flow in detail, are described. Here, the spectrum Doppler mode is described as an example. It shall be. In these modes, pressure gradient, pressure half time, velocity slope, left ventricular end diastolic volume, left ventricular end systolic volume, stroke volume, RI (Res
Although various measurements such as an instance index (PI) and a PI (Pulsatility Index) can be performed, here, the RI will be described as an example.

First, as is well known, the ultrasonic probe 1 is equipped with an array structure of minute vibrators having electrodes arranged on both sides of a piezoelectric element near its distal end. The exchange of signals and electric signals is realized.
The ultrasonic probe 11 transmits and receives a high-frequency drive signal pulse to the vibrator to irradiate the ultrasonic wave to the subject, and receives an echo returned from the subject to generate an echo signal. The circuit 13 is connected.

The transmitting / receiving circuit 13 includes a reference signal generator 2
0, and the reference frequency f distributed over the number of channels
_The transmission part is configured so that the reference signals of ₀ are individually appropriately delayed by the delay line 21, amplified by the pulser 23, and output as drive signal pulses to the vibrator individually or for each channel. . By such a drive signal pulse, the center frequency is f ₀ from the probe 11.
Is irradiated toward the subject.

Further, the transmitting / receiving circuit 13 individually amplifies a plurality of electric signals output for each transducer or each channel as a receiving portion for receiving an echo reflected at a boundary surface of acoustic impedance in the subject. , A transmission / delay line 21 for individually delaying the amplified electric signal, and an adder 27 for forming a directional echo signal by adding a plurality of delayed electric signals. Equipped.

The echo signal formed by the transmission / reception circuit 13 is first logarithmically amplified by a detector 29 and then envelope detected. This detection signal reflects a tissue structure on one line (also referred to as an ultrasonic scanning line) of an azimuth and a position according to transmission / reception delay control, that is, a one-dimensional tissue image. In the case of sector scanning, a plurality of one-dimensional tissue images having different line orientations are collected while gradually changing the transmission / reception delay time, and these are arranged by the digital scan converter 30 according to the respective orientations. A so-called M-mode image is a B-mode image representing a cross-sectional tissue structure, and a one-dimensional tissue image of the same orientation arranged in parallel along the time axis.

The echo signal formed by the transmission / reception circuit 13 is also sent to the mixer 40, where the reference signal having the frequency f ₀ sent directly from the reference signal generator 20 and the reference signal from the reference signal generator 20 are sent. The phase shifter 41 individually mixes the reference signal with the frequency f ₀ shifted by 90 °. The Doppler shift frequency is set to f _d
As the frequency of the echo signal (f ₀ + f _d) and the frequency component of the sum of the frequency f ₀ of the reference signal _{(2 · f 0 + f d} )
And the frequency component (f _d ) of the difference, the mixed signal is passed through the low-pass filter 43 in order to extract the required Doppler shift frequency f _d .

The Doppler shift frequency f thus extracted
_For a Doppler signal having _d , a signal within a region of interest called a sample volume set to an arbitrary width at an arbitrary depth by an operator is cut out by a range gate circuit 60,
The extracted signal is sent to the sample and hold circuit 61. The sample hold circuit 61 holds signals related to the same sample volume for 64 transmissions and receptions, for example. The 64 signal trains discrete at the pulse repetition period (1 / PRF) include not only necessary reflected components from blood cells but also reflected components from living tissue having an amplitude several hundred times larger than that. Since it is included, it is removed by a band-pass filter 63, converted into a digital signal by an analog-to-digital converter 65, and then subjected to real-time frequency analysis by a fast Fourier transformer (FFT) 67 to obtain a frequency component ( A frequency spectrum representing the intensity of each velocity is obtained, here, the frequency spectrum of the blood flow.

A so-called spectrum Doppler mode image is obtained by arranging such blood flow spectra in parallel along the time axis by the digital scan converter 30 so that a temporal change of the blood flow pattern can be recognized.

Although not shown, similar to the above-described M mode in which the temporal change of the tissue is known and the spectrum Doppler mode in which the temporal change of the blood flow pattern is known, the temporal change is represented by a time axis. As a technique that can be represented, a technique called a color flow mapping mode, which can obtain a two-dimensional image of the average speed, dispersion, and power in real time using an MTI filter and an autocorrelator, is applied. One-dimensional color blood flow images of average velocity, variance, and power on the line are arranged in parallel along the time axis and displayed in color, so that the state of blood flow on the line can be observed over time. So-called MDF
There is a display method called a mode.

Information such as a one-dimensional tissue image, a blood flow spectrum, and a one-dimensional color blood flow image are arranged along the time axis by the digital scan converter 30.
This is sent to the display 3 via the digital / analog converter 31.
3 is displayed in shades or colors.

By the way, as described in the prior art, M
Using a type of image that displays various changes over time, such as mode, spectrum Doppler mode, and MDF mode, left ventricular end diastolic volume, left ventricular end systolic volume, pressure gradient, pressure half time, velocity slope (acceleration measurement) Stroke volume, cardiac output, RI (Resistance Inde
Indices in which various time factors such as x) and PI (Pulsatility Index) are important are measured.

The present invention is a novel technique relating to a method for displaying these measurement results. In the present embodiment, this will be described in the spectrum Doppler mode using RI as an example. As is well known, the spectrum Doppler mode sets a sample volume on a blood flow of a site of interest, for example, an umbilical artery or a uterine artery on a B-mode image, and sets a spectrum of the blood flow in the sample volume, that is, the blood flow. The spectrum of the frequency shifted (shift frequency) is periodically obtained, and the blood flow spectrum is arranged along the time axis to obtain a time waveform (Doppler image), which is displayed.

On the other hand, RI is an index value of intrauterine circulation and maternal circulation for use in diagnosing the severity of intrauterine growth delay and the diagnosis of preeclampsia from the time waveform of the blood flow spectrum of the umbilical artery and uterine artery. The maximum flow rate in systole within one heartbeat is S, and the flow rate in end diastole within one heartbeat is D, (S−
D) / S, which is calculated one by one in one heartbeat period.

Normally, as shown in FIG. 2, a time waveform of a blood flow spectrum, that is, a Doppler image is displayed on the display unit 33 with a time width of, for example, 4 seconds from 4 seconds ago to the present.
When a new blood flow spectrum is obtained by the next scan, the oldest blood flow spectrum is deleted from the immediately preceding Doppler image, and the latest blood flow spectrum obtained by the next scan is added. By repeating such an update operation in synchronization with the scan, the time waveform of the blood flow spectrum is continuously displayed while scrolling from the right to the left of the screen at a scroll speed of 4 seconds, for example. You can do it.

Such a display method is realized by erasing, writing, and reading address control on the digital scan converter 30 of the display control unit 35.
Practically, the blood flow spectrum data from the spectrum Doppler calculation unit 50 is represented by a two-dimensional coordinate system of time and frequency. The display control unit 35 converts such blood flow spectrum data into a two-dimensional orthogonal coordinate system of an X axis (vertical axis, frequency axis) and a Y axis (horizontal axis, time axis), and converts the data into a digital scan converter 30. Write to the frame memory of Then, the display control unit 35 sequentially reads out the Doppler image data for 4 seconds stored in the frame memory of the digital scan converter 30 as a one-dimensional signal according to the television scanning method of the display unit 33.

In this embodiment, as shown in FIG. 2, the time curve of the RI, that is, the RI graph is four times longer than the time of 4 seconds of the Doppler image, for example, 4 minutes before to the present time. It is displayed on the display unit 33 with a time width of minutes. When the RI is newly calculated in the next heartbeat period, the oldest RI dot is deleted from the immediately preceding RI graph, and the latest RI dot is added. Such an update operation,
By repeating in synchronization with the heartbeat cycle, the RI time curve can be displayed continuously while scrolling from the right to the left of the screen at a scroll speed of 4 minutes, for example. .

Such a display method is also realized by erasing, writing, and reading address control on the digital scan converter 30 of the display control unit 35, similarly to the case of the Doppler image. Actually, the RI measurement unit 80
Is simply expressed in a one-dimensional coordinate system of time (heartbeat period) only. The display control unit 35 converts such RI data into an X axis (vertical axis, numerical value), Y
The data is converted into a two-dimensional orthogonal coordinate system of axes (horizontal axis, time axis) and written in the frame memory of the digital scan converter 30. Then, the display control unit 35 sequentially reads out the four-second RI graph data held in the frame memory of the digital scan converter 30 together with the Doppler image data as a one-dimensional signal in accordance with the television scanning method of the display unit 33.

By displaying the time graph of the measured values such as RI on the same screen as the time waveform (Doppler image) of the blood flow spectrum with a longer time width than the Doppler image, only one value per heartbeat can be obtained. Even with a count value such as RI that cannot be obtained, it is possible to observe minute time changes,
It becomes easier to catch changes over time. It is needless to say that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

[0026]

According to the present invention, the time graph of the ultrasonic information on an arbitrary line in the subject and the time graph of the measured value measured based on the ultrasonic information are displayed with different time widths. Since it is displayed, for example, even with a count value such as RI in which only one value is obtained in one heartbeat, it is easy to catch a change with time.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an example of a display screen created by a digital scan converter under the control of the display control unit in FIG. 1 and displayed on the display unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Ultrasonic probe, 13 ... Transmission / reception circuit, 20 ... Reference signal generation part, 21 ... Delay line, 23 ... Pulser, 25 ... Preamplifier, 27 ... Adder, 29 ... Detector, 30 ... Digital scan converter, 31 ... Digital Analog converter, 33 ... Display unit, 35 ... Display control unit, 40 ... Mixer, 41 ... 90 ° phase shifter, 43 ... Low pass filter, 50 ... Spectral Doppler operation unit, 60 ... Range gate circuit, 61 ... Sample hold circuit 63, a band-pass filter, 65, an analog-to-digital converter, 67, a fast Fourier converter, 80, an RI measuring unit.

Claims (4)

[Claims] 1. Ultrasound information on an arbitrary line in a subject is displayed over time, and a time graph of measured values measured based on the ultrasound information is displayed on the same screen as the ultrasound information. An ultrasonic diagnostic apparatus, wherein a time graph of the measured value and a time width of the ultrasonic information are displayed different from each other. 2. The ultrasonic information is a one-dimensional tissue image on the line, and the one-dimensional tissue images are arranged along a time axis and displayed in an M mode. Ultrasonic diagnostic equipment. 3. The ultrasonic information is a blood flow spectrum of a sample volume at an arbitrary depth on the line,
2. The ultrasonic diagnostic apparatus according to claim 1, wherein the blood flow spectrum is arranged and displayed along a time axis. 4. Ultrasound information on an arbitrary line in the subject is displayed over time, and a time graph of measured values measured based on the ultrasound information is displayed on the same screen as the ultrasound information. In the ultrasonic diagnostic apparatus, the time graph of the measured value is scrolled at a lower speed than the ultrasonic information.