JPH078495A - Scanning method in ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To provide the scanning method for ultrasonic diagnostic device by improving the sample rate while preventing the influence of multiplex echos due to the reverberation soundwave and securing the continuity of picture. CONSTITUTION:The ultrasonic diagnostic device scans and fetches data by multistage-focusing the ultrasonic beam to each scanning line of the scanning area having plural scanning lines. The scanning is performed by focusing in a manner of the mutistage transmission by the prescribed scanning line in the range on plural scanning lines located at almost synmetrical position between the right and left positions within the prescribed range from the symmetrical axis of the scanning area. S1, S2, and S3. By repeating the multistage transmission focus scanning for the other scanning lines within the rang. The scaning of plural scanning lines within the pertinent range is performed. S4, S5, and S6. Then, the multistage transmission focus scaning is repeated while alternately performing scanning a pair of scanning lines located at about symetrical positions outside the prescribed range from the synmetrical axis one by one stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning method in an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus capable of obtaining high resolution over a wide range in the distance direction by multi-stage transmission focus and ultrasonic waves at a constant repetition cycle. Send a pulse,
The present invention relates to a scanning method in an ultrasonic diagnostic apparatus that is suitable for scanning a wide area at a short frame rate in an ultrasonic Doppler diagnostic apparatus that detects the Doppler shift frequency from a moving reflector and displays the moving speed of the moving reflector.

[0002]

2. Description of the Related Art In a general ultrasonic diagnostic apparatus using B-mode scanning, the resolution of an ultrasonic image is improved by increasing the number of transmission focus points in the depth direction.

FIG. 4 shows an example of a conventional scanning method in the ultrasonic diagnostic apparatus as described above, and particularly illustrates the case of multi-stage focus transmission.

As is clear from the figure, first, the transmission point S
The first transmission S1 focused on the shallowest place from P is performed, the second transmission S2 focused on the deeper place is performed next, and the third transmission S3 focused on the deeper place is performed.
Data acquisition is performed by transmitting ultrasonic waves focused on different depths in the same transmission / reception direction and receiving ultrasonic waves reflected from each focus portion. Next, the transmission / reception direction of ultrasonic waves is shifted toward the scanning direction SC, and similarly, the fourth transmission S4 in which the focus is located at the shallowest position from the transmission point SP is performed, and then the fifth transmission is performed in the deeper part. Transmission S5 is performed, and a sixth transmission S6 focusing on a deeper place is performed to diagnose a different depth. By repeating the above-described operation sequentially in the scanning direction SC, a wide range of ultrasonic diagnosis can be performed.

However, in the case of multi-stage focusing, since ultrasonic waves are transmitted and received a plurality of times in the same direction, in order to avoid interference between the transmitted wave and the reflected wave, the ultrasonic wave is transmitted in anticipation of the time until the reflected wave is received. Interval, that is, transmission repetition frequency PRF
Is determined. For this reason, it takes a long time to make a diagnosis at one location, and eventually, the time until the entire scanning is finished also becomes long. As a result, there is a problem that the repetition period of one frame obtained by performing one scan in the scanning direction SC, that is, the frame rate is reduced.

In order to improve the frame rate, it is necessary to reduce the transmission repetition frequency PRF.
Therefore, when focusing on a shallow portion, focusing on the fact that the distance is short and the time required from ultrasonic transmission to reception of reflected waves is short, the ultrasonic transmission repetition frequency PRF is changed according to the focus position. Is being considered. In this case, the tip of each arrow in FIG. 4 indicates the ultrasonic wave reception completion point.

FIG. 5 is a timing chart for explaining the operation of the method of FIG. 4 when such a method is adopted. In the figure, (A) shows transmission trigger signals (TRG1, TRG2, TRG) for transmitting ultrasonic waves from the transmission point SP.
3) and (B) are transmission waves (SW1, SW2, SW3) based on the transmission trigger signal shown in (A), and (C) shows the position of the reflector (RB1, RB2) corresponding to the specimen in the depth direction. Is. (D) is the received wave from the reflector (RW1, R
W2, RW3).

Now, as shown in (A), the transmission trigger signals TRG1, TRG2, TRG3 correspond to the transmission repetition frequency PRF and the transmission repetition periods 1 / PRF1 and 1 / P.
It is output for each RF2, 1 / PRF3. Now, it is assumed that the diagnostic period corresponding to the transmission trigger signal TRG1 is a period T1, the diagnostic period corresponding to the transmission trigger signal TRG2 is a period T2, and the diagnostic period corresponding to the transmission trigger signal TRG3 is a period T3. When the transmission wave SW1 is transmitted in the period T1, the reception wave RW1 is received by being reflected by the reflector RB1. However, when the reflector RB2 exists at different depths in the living body, the received wave RW2 is received as a multiple echo by the reverberant sound wave. This reception wave RW2 leaks into the next period T2 if the period T1 is short. However, during the period T2, the transmission wave SW2 based on the next transmission trigger signal TRG2 is transmitted,
While it is normal to receive the reception wave RW3 based on the reflector RB1, the reception wave RW2 is received first, and this appears as an artifact on the tomographic image.

Therefore, in the ultrasonic diagnostic method as shown in FIG. 4, it is necessary to consider the appearance of noise due to multiple echoes, and therefore the periods T1 and T2 cannot be significantly shortened.

In order to solve this problem, the conventional method shown in FIG.
As shown in, the scan areas are scan area SC1 and scan area S
There is a method of scanning by dividing into C2 and two. That is,
First, in the scanning area SC1, the first transmission S1 focused on the shallowest point from the transmission point SP is performed, and then, the second transmission S2 focused on the shallowest location from the transmission point SP is performed by moving to the scanning area SC2. . Next, returning to the scanning area SC1, the third transmission S3 focused on a deeper area is performed, and the fourth transmission S4 focused on a deeper area is performed after moving to the scanning area SC2. Then, returning to the scanning region SC1, the fifth transmission S5 focusing on the deepest part is performed,
Moving to the scanning area SC2, the sixth transmission S6 focusing on the deepest part is performed. Then, a diagnosis is performed on a portion focused on three depths at the same location on each of the scanning regions SC1 and SC2.

Following the above-mentioned operation, this time, in the scanning area SC1, the transmission / reception direction is shifted in the main scanning direction, and the seventh transmission S focused on the shallowest point from the transmission point SP.
Do 7. Next, the scan area SC2 is moved to and the scan area SC1 is moved.
Corresponding to, the transmission / reception direction is shifted in the main scanning direction, and the eighth transmission S8 focusing on the shallowest position from the transmission point SP is performed. Next, returning to the scanning area SC1, the ninth transmission S9 focused on a deeper area is performed, and the scanning area SC2 is moved to a tenth transmission S10 focused on a deeper area. Subsequently, the eleventh transmission S11 focusing on the deepest part is performed by returning to the scanning area SC1 and scanning area SC2.
Then, the twelfth transmission S12 focusing on the deepest part is performed.

By repeating the above operation,
When all the main scans of the two scan areas SC1 and SC2 are completed, the data acquisition of one frame is completed.

In the scanning method described above, each transmission is alternately performed in the scanning area SC1 while repeating the first transmission S1, the second transmission S2, ... The nth transmission Sn in sequence.
Therefore, the influence of multiple echoes is unlikely to leak into the next reception period, and the transmission interval in scan region SC1 and the transmission interval in scan region SC2 are not affected by multiple echoes. It suffices that the ultrasonic wave transmission interval is set. Therefore, the transmission interval of each ultrasonic wave, that is, the transmission repetition period 1 / PRF can be significantly shortened.

[0014]

However, the scanning area SC
1, the transmission time differs in the boundary area between 1 and the scan area SC2,
A time interval equal to one frame time is opened. For example, if the frame rate is 20 frames / second, a time interval of about 1/20 second will be opened. This causes a temporal discontinuity point between the scan region SC1 and the scan region SC2. Since this time also corresponds to the difference between the opening and closing of the valve in the heart, for example, a discontinuous portion will occur in the obtained diagnostic image.

As described above, in the scanning method in the conventional ultrasonic diagnostic apparatus as shown in FIG. 4, although the continuity of images can be obtained, the transmission is performed when the multi-stage focus ultrasonic diagnosis is performed. If the repetition period 1 / PRF is made too short, noise increases due to the effect of multiple echoes,
While there is a problem in that the frame rate cannot be improved, as shown in FIG. 6, when the scanning area is divided into a plurality of areas and each area is diagnosed in a time division manner, the effect of multiple echoes occurs. Although the sampling rate can be improved by reducing the number of pixels, there is a problem that the continuity of images is not maintained and it is difficult to diagnose moving objects. Such a problem also applies to the Doppler tomographic image. While the transmission repetition frequency PRF is increased N times in order to increase the scanning frame rate, a 1 / N rate is maintained in order to keep the sample rate constant. In the case where the transmission of one scanning line is equivalently thinned while alternately transmitting on a plurality of scanning lines adjacent to each other, there is a problem that the influence of multiple echoes is increased due to the shortened reception time.

Therefore, the present invention has been made in order to solve the above-mentioned problems of the prior art. In the scanning method of the ultrasonic diagnostic apparatus, the sample rate is avoided while avoiding the influence of multiple echoes due to reverberant sound waves. It is an object of the present invention to provide a scanning method of an ultrasonic diagnostic apparatus that can improve the image quality and ensure the continuity of images.

[0017]

In order to achieve the above object, the present invention is, firstly, to carry out data acquisition by scanning an ultrasonic beam with a multi-stage focusing on each scanning line of a scanning region having a plurality of scanning lines. In the ultrasonic diagnostic apparatus to perform, for a plurality of scanning lines within a predetermined range from the axis of symmetry of the scanning region and at substantially left-right symmetric positions, multistage transmission focus is performed from the predetermined scanning lines within the range to perform scanning, Scanning of a plurality of scanning lines within the range is repeated by repeating the multi-stage transmission focus scanning on the other scanning lines inside, and then a plurality of pairs of scanning lines located outside the predetermined range from the axis of symmetry and located at substantially left-right symmetry positions. With respect to the above, the multi-stage transmission focus scanning is repeated while alternately scanning the scanning lines forming a pair one by one.

Secondly, in the first structure, scanning lines within a predetermined range from the axis of symmetry of the scanning region are scanned by multistage transmission focus from scanning lines on the axis of symmetry. Next, with respect to a plurality of pairs of scanning lines at the left-right symmetric position from the axis of symmetry, the scanning is gradually performed toward both ends of the scanning region, and one of the scanning lines forming a pair is subjected to multi-stage transmission focus and then the other scanning line is scanned. Multi-stage transmission focus is performed on the scanning lines, and for a plurality of pairs of scanning lines that are outside the predetermined range from the axis of symmetry and are in a substantially symmetrical position, scanning is performed from the scanning line closest to the axis of symmetry to the scanning lines at both ends. The scanning is completed on the scanning lines located at both ends of the scanning area.

Thirdly, in an ultrasonic diagnostic apparatus which scans each scanning line of a scanning region having a plurality of scanning lines by focusing an ultrasonic beam in multiple stages to capture data, a predetermined distance from the axis of symmetry of the scanning region. With respect to a plurality of pairs of scanning lines which are out of the range and which are substantially symmetrical to each other, multistage transmission focus scanning is repeated while alternately scanning one pair of predetermined scanning lines, and then within a predetermined range from the symmetry axis. Yes For a plurality of scanning lines at substantially symmetrical positions, multistage transmission focus is performed from a predetermined scanning line within the above range for scanning, and multistage transmission focus scanning is repeated for other scanning lines within the above range It is characterized in that a plurality of scanning lines in the inside are scanned.

Further, fourthly, with respect to a plurality of pairs of scanning lines which are outside the predetermined range from the axis of symmetry of the scanning region and which are substantially symmetrical to each other, scanning is performed from the scanning lines located at both ends of the scanning region, and gradually. Scanning toward the symmetry axis side, and scan lines within a predetermined range from the symmetry axis of the scanning area are scanned from the scan lines closest to both ends, and the multi-stage transmission focus on the scan lines on the symmetry axis. And scanning is completed.

[0021]

In the scanning method of the ultrasonic diagnostic apparatus having the above-described structure, first, a plurality of scanning lines which are within a predetermined range from the axis of symmetry of a scanning region having a plurality of scanning lines and which are substantially symmetrically positioned are first scanned. That is, a predetermined scanning line within the above range is subjected to multi-stage transmission focus for scanning, and then another scanning line within the above range is subjected to multi-stage transmission focus scanning. The multi-stage transmission focus as described above is repeated to scan a plurality of scanning lines within the range. Next, with respect to a plurality of pairs of scanning lines which are outside the predetermined range from the axis of symmetry and which are located in a substantially left-right symmetrical position, the multi-stage transmission focus scanning is repeated while alternately scanning the scanning lines forming a pair one by one. That is, after scanning one stage of a certain scanning line, scanning is performed about one stage of another scanning line which is located at a substantially symmetrical position. Next, scanning is performed again on one stage of the original scanning line. As described above, scanning is performed while alternately performing left and right multi-stage transmission focus scanning. In the present invention, since the time interval of transmission between two scanning lines is short for any adjacent scanning lines, the continuity of images can be improved. Further, for scanning lines outside the predetermined range, scanning is alternately performed for each pair of scanning lines, so that the transmission repetition period can be shortened and the frame rate can be improved.

In the second structure, the scanning lines within a predetermined range from the symmetry axis of the scanning region are scanned by multistage transmission focus from the scanning lines on the symmetry axis, and then the symmetry is performed. For a plurality of pairs of scanning lines at symmetrical positions from the axis, gradually toward both ends of the scanning region,
Multi-stage transmission focus is performed on one of the scanning lines forming a pair, and then multi-stage transmission focus is performed on the other scanning line.
Next, with respect to a plurality of pairs of scanning lines that are located outside the predetermined range from the axis of symmetry and are located in a substantially left-right symmetrical position, multi-stage transmission focus scanning is performed while alternately scanning one pair of scanning lines that are closest to the axis of symmetry. Then, scanning lines adjacent to the pair of scanning lines are similarly subjected to multi-stage transmission focus and scanning is performed. That is, scanning is performed from the scanning line closest to the symmetry axis toward the scanning lines at both ends, and the scanning is completed at the scanning lines located at both ends of the scanning region. If the scanning is performed as described above, the scanning is gradually performed from the symmetry axis of the scanning region toward both ends, so that the continuity of the image can be improved.

Next, in the third configuration, unlike the first and second configurations, scanning is performed from a scanning line outside a predetermined range from the symmetry axis of the scanning region. That is, with respect to a plurality of pairs of scanning lines that are outside the above-mentioned predetermined range and are located in a substantially left-right symmetrical position, multi-stage transmission focus scanning is repeated while alternately scanning one pair of predetermined scanning lines, and then the above-mentioned symmetry axis. From a predetermined scanning line in the above range, multi-step transmission focus is performed on a plurality of scanning lines in a predetermined range within a predetermined range from the predetermined scanning line, and multi-step transmission focus scanning is performed on other scanning lines in the above range. By repeating this, a plurality of scanning lines within the range are scanned. When the scanning is performed as described above, a plurality of scanning lines within the predetermined range of the scanning range are scanned separately from the scanning lines outside the predetermined range, so that the continuity of the image can be maintained. In particular, the continuity of an image can be improved by scanning a scanning line adjacent to a scanning line after scanning a scanning line. Further, for scanning lines outside the predetermined range, scanning is alternately performed for each pair of scanning lines, so that the transmission repetition period can be shortened and the frame rate can be improved.

Further, in the fourth configuration, with respect to a plurality of pairs of scanning lines which are located outside the predetermined range from the axis of symmetry of the scanning region and are located at the substantially left-right symmetric position, a pair of scanning lines symmetrically positioned at both ends of the scanning region are formed. Multi-stage transmission focus scanning is performed while alternately scanning the lines one by one, and then scanning lines adjacent to the pair of scan lines are similarly subjected to multi-stage transmission focusing to perform scanning, and gradually the symmetry axis side Scan toward. Further, for a scanning line within a predetermined range from the axis of symmetry of the scanning region, the scanning line closest to both ends is scanned, and among a plurality of pairs of scanning lines located symmetrically from the axis of symmetry, the scanning line is closest to both ends. After performing multi-stage transmission focus on one of the pair of scan lines, multi-stage transmission focus is performed on the other scan line, and similar scanning is performed gradually toward the symmetry axis of the scan region. Then, the scanning is completed by the scanning lines on the axis of symmetry. If the scanning is performed as described above, the scanning is gradually performed from both ends of the scanning area toward the axis of symmetry, so that the continuity of the image can be improved.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of a scanning method of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. As shown in the drawing, the scanning method at one transmission / reception position is multi-stage focus, and at each position, transmission is performed three times while switching the transmission focus position. The entire scan area is a fan-shaped scan area, and scan areas SC1 and SC2 are set, and a substantially central portion of the entire scan area is a boundary area between scan areas SC1 and SC2.

In this case, the scanning is first started from the symmetry axis of the scanning area, that is, the boundary area between the scanning areas SC1 and SC2. At this point, the first transmission S1 focused on the shallowest point from the transmission point SP is performed, and then the second transmission S2 focused on the deeper point is performed.
The third transmission S3 focused on a deeper place is performed, ultrasonic waves focused on different depths in the same direction are transmitted, reflected waves are received, and data is captured. At this point, in order to eliminate the influence of multiple echoes, the transmission repetition period 1 / PRF of each of the first transmission S1, the second transmission S2, and the third transmission S3 is set sufficiently long.

Next, the transmission / reception direction is shifted to the adjacent scanning line on the scanning region SC1 side, the fourth transmission S4 focused on the shallowest point from the transmission point SP is performed, and then at the same position, at a deeper point. The fifth transmission S5 focused on is performed, and the sixth transmission S6 focused on a deeper place is performed. Even at this position, in order to eliminate the influence of multiple echoes, the transmission repetition period 1 / PRF of each of the first transmission S1, the second transmission S2, and the third transmission S3 is set sufficiently long.

Next, the scanning line SC2 is shifted to the scanning lines which are symmetrically positioned via the axis of symmetry, and the seventh transmission S7 focusing on the shallowest point from the transmission point SP is performed, and then the same direction is followed. Eighth transmission S8 focused on deep places
Then, the ninth transmission S9 focusing on a deeper place is performed. Even at this position, in order to eliminate the influence of multiple echoes, the transmission repetition period 1 / PRF of each of the first transmission S1, the second transmission S2, and the third transmission S3 is set sufficiently long.

As described above, for the scanning lines within the predetermined range from the axis of symmetry, the scanning lines on the axis of symmetry are subjected to the multi-stage transmission focus scanning, then the scanning of the adjacent scanning lines is performed, and then, The scanning lines that are symmetrically positioned are scanned, and the transmission / reception direction is gradually shifted outward.

Next, when the scanning position is sufficiently separated from the axis of symmetry, that is, the boundary region between the scanning region SC1 and the scanning region SC2, the order of focus switching and scanning position switching is set to a procedure different from that in the past.

That is, first, in the scan area SC1,
The process starts from the tenth transmission S10 focused on the shallowest point from the transmission point SP. Next, the process moves to the scanning area SC2 and the eleventh transmission S11 focused on the second shallowest point from the transmission point SP is performed. Next, returning to the scanning area SC1, the twelfth transmission S12 focused on the deepest portion is performed, and the first area focused on the shallowest portion is moved to the scanning area SC2.
Transmission S13 of 3 is performed. Subsequently, returning to the scanning region SC1, the 14th transmission S14 focused on the second shallowest place is performed, and the scanning region SC2 is moved to the 15th transmission S15 focused on the deepest place. As described above, in each of the scanning areas SC1 and SC2, a portion focused on three depths can be diagnosed at a position substantially distant from both areas.
Moreover, since each transmission is alternately performed in the scan region SC1 and the scan region SC2, the influence of multiple echoes can be ignored, and thus the transmission repetition period 1 / PRF can be significantly shortened.

Following the above operation, the scanning area SC
1, at the scan position farther from the boundary region of SC2, the sixteenth transmission S16 in the scan region SC1 and the seventeenth transmission S17 in the scan region SC2,
Eighteenth transmission S18 in the scanning area SC1, nineteenth transmission S19 in the scanning area SC2, twentieth transmission S20 in the scanning area SC1, twenty-first transmission S21 in the scanning area SC2, and scanning area SC1 and scanning in sequence. Ultrasonic waves are alternately transmitted and received in the region SC2. Also in this case, since each transmission / reception is alternately performed in the scan area SC1 and the scan area SC2, the influence of multiple echoes between each transmission / reception is small, so that the transmission repetition cycle 1 / PRF can be greatly shortened.

As a result of the above operation, the scanning area SC1
In the boundary area between the scan area SC2 and the scan area SC2, the transmission repetition cycle 1 / P
Although it is necessary to lengthen the RF, the effect of multiple echoes decreases as the scanning position moves away from the boundary area, so that the transmission repetition period 1 / PRF can be shortened. As a result, the total time of the entire transmission repetition period 1 / PRF becomes short, and the frame rate can be reduced.

Further, in each of the scan area SC1 and the scan area SC2, since the scan position is changed in the direction away from the boundary area, the temporal difference in the boundary area is small, and therefore the temporal discontinuity is eliminated. Images with continuity can be obtained.

FIG. 2 is an explanatory view of an ultrasonic diagnostic method according to another embodiment of the present invention, and particularly shows an operation for displaying an ultrasonic Doppler tomographic image. As is clear from the figure, transmission / reception of ultrasonic waves is repeated three times at each transmission position, and scanning regions SC1 and SC2 in which scanning is divided into two are performed.
The example illustrates the case of starting from the boundary position of, that is, approximately the center of the entire scanning area.

At the start of scanning, the scanning area SC
In the boundary area of 1 and SC2, the first transmission S1 to the third transmission
Transmission S3 is continuously performed. In this case, each transmission repetition period 1 / PRF is set to a time at which the influence of multiple echoes can be eliminated and a sampling frequency for Doppler shift detection can be obtained.

Next, the process moves to an adjacent transmission position in the direction away from the boundary region on the scanning region SC1 side, where the fourth transmission S4 to the sixth transmission S6 are continuously performed. Also in this case, each transmission repetition period 1 / PRF is set to a time at which the influence of multiple echoes can be eliminated and a sampling frequency for Doppler shift detection can be obtained.

Next, the process moves to the adjacent transmission position on the scanning area SC2 side, where the seventh transmission S7 to the ninth transmission S9 are continuously performed. Also in this case, each transmission repetition period 1 / PRF
Is set to the time at which the sampling frequency for Doppler shift detection is obtained.

Next, the process moves to the adjacent transmission position in the direction away from the boundary region on the scanning region SC1 side, but here, the eleventh transmission S11 is first performed. And this time, the scan area SC
Moving to 2, the twelfth transmission S12 is performed at the transmission positions adjacent to each other in the direction away from the boundary area. It should be noted that if the transmission / reception positions are separated from each other to the extent that the multiple echo of the eleventh transmission S11 does not affect the twelfth transmission S12,
It is possible to shorten the transmission repetition period 1 / PRF between the transmission S11 and the twelfth transmission S12 to about one half of that.

After that, similarly, the transmission / reception of ultrasonic waves is continuously switched from the thirteenth transmission S13 to the nth transmission Sn while alternately switching the transmission position between the scanning region SC1 and the scanning region SC2. In this case, the transmission repetition period 1 / P
Although the RF is halved, the sample frequency for detecting the Doppler shift can be maintained the same as that near the symmetry axis by alternately transmitting the right and left.

As a result of the above operation, the overall frame rate can be greatly reduced. on the other hand,
With respect to any two adjacent scanning lines, the time difference between transmission and reception on each scanning line is very small, so that image continuity can be ensured and a good diagnostic image can be obtained.

In the example of FIG. 2, the number of times of transmission of one ultrasonic wave at the transmission / reception point is set to 3 times, but generally, about 10 times of transmission is performed. This number of transmissions can be set to any number according to the request of the diagnostic device, and the same effect can be obtained.

In each of the above-described embodiments, the scanning is started with the vicinity of the boundary area of the plurality of scanning areas as the starting point, but on the contrary, the scanning is started from both ends of the scanning area, and the scanning is started with the boundaries of the scanning area as the end points. However, it is possible to improve the frame rate while ensuring the continuity of images.

FIG. 3 is a block diagram of an apparatus for realizing the ultrasonic diagnostic method of the present invention. In the figure, 1 is a living body to be diagnosed, 14 is in contact with the living body 1,
A probe that transmits ultrasonic waves to the inside of the living body 1 and receives reflected ultrasonic waves, 2 is an ultrasonic transceiver that transmits and receives ultrasonic signals through the probe 14, and 10 is a probe that transmits ultrasonic waves from the probe 14 through the ultrasonic transceiver 2. A scanning controller for sector-scanning transmitted and received ultrasonic waves, 9 is a timing signal generator for controlling the ultrasonic transmission repetition frequency PRF in the scanning controller 10, and 5 is a transmission timing signal generated by the timing signal generator 9. An orthogonal transformer that multiplies the timing signals of the ultrasonic waves received by the ultrasonic transceiver 2 for orthogonal transformation, 6 is a clutter removal filter that removes noise from the output of the orthogonal transformer 5, and 7 is obtained through the clutter removal filter 6. An autocorrelator to take the autocorrelation of the signal,
Reference numeral 8 is a speed calculator for calculating the speed based on the output signal of the autocorrelator 7, 3 is a detector for extracting a reflected signal component from the reception signal of the ultrasonic transceiver 2, and 4 is digital conversion of the output of the detector 3. An A / D converter, 11 is a D.D. that outputs a signal suitable for display by scan-converting the output of the A / D converter 4 based on the outputs of the scan controller 10 and the speed calculator 8.
S. C. (Digital scan converter), 12 is D. S. C. Reference numeral 13 is a D / A converter for converting the output of 11 into analog, and 13 is a display 13 for displaying the output of the D / A converter 12 as a visible image.

Through the above configuration, the timing signal generator 9 is transmitted from the ultrasonic transmitter / receiver 2 through the probe 14.
The ultrasonic waves sent into the living body 1 at the transmission repetition cycle 1 / PRF determined by 1 generate a reflected wave according to the situation inside the living body 1. The reflected wave is detected by the probe 14 and the ultrasonic transmitter / receiver 2 To the detector 3 through. Detector 3
The received signal detected by the D.C. is digitally converted by the A / D converter 4, and the D.D. S. C. The data is displayed from 11 through the D / A converter 12 and the display unit 13. For this visualization, timing control is performed by the orthogonal converter 5, the clutter removal filter 6, the autocorrelator 7, and the speed calculator 8. D. S.
C. Reference numeral 11 converts the signal from the A / D converter 4 into a signal having a timing suitable for display based on the output signals of the speed calculator 8 and the scan controller 10. It should be noted that the sector scanning by the probe 14 and the transmission repetition cycle 1 / PRF at each scanning position
Is controlled through the timing signal generator 9 and the scanning controller 10, and timing control for reducing the overall frame rate is performed.

In the above embodiment, the sector scanning is explained as an example, but other scanning methods such as linear scanning,
Even in other systems such as arc scanning, a system in which the transmission repetition cycle 1 / PRF is switched depending on the presence or absence of the influence of multiple echoes is effective, and the frame rate can be shortened.

[0048]

According to the present invention, since a plurality of scanning lines within a predetermined range from the axis of symmetry are scanned separately from scanning lines outside the predetermined range, the continuity of the image and the feature near the center is maintained. be able to.

Further, when the pair of scanning lines at the symmetrical positions are separated from each other to the extent that they are not affected by the afterimage echo, the repetition period can be shortened, so that the frame rate can be improved as a whole.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an ultrasonic diagnostic method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an ultrasonic diagnostic method according to another embodiment of the present invention.

FIG. 3 is a block diagram of a configuration for implementing the present invention.

FIG. 4 is an explanatory diagram of an example of a conventional ultrasonic diagnostic method.

FIG. 5 is a timing chart for explaining the operation of FIG.

FIG. 6 is an explanatory diagram of another example of a conventional ultrasonic diagnostic method.

[Explanation of symbols]

 1 living body 2 ultrasonic wave transmitter / receiver 3 detector 4 A / D converter 5 orthogonal converter 6 clutter removal filter 7 autocorrelator 8 velocity calculator 9 timing signal generator 10 scan controller 11 D. S. C. 12 D / A converter 13 Display 14 Probe

Claims (4)

[Claims] 1. An ultrasonic diagnostic apparatus for performing multi-stage ultrasonic beam focusing on each scanning line of a scanning region having a plurality of scanning lines to acquire data, wherein the scanning line is within a predetermined range from a symmetry axis of the scanning region. For a plurality of scanning lines at symmetrical positions, multi-stage transmission focus is performed from a predetermined scanning line within the above range to perform scanning, and multi-stage transmission focus scanning is repeated for other scanning lines within the above range to within the range. A plurality of scanning lines are scanned, and then, with respect to a plurality of pairs of scanning lines which are outside the predetermined range from the above-mentioned axis of symmetry and are located in a substantially left-right symmetric position, the scanning lines forming a pair are alternately scanned one by one, and multi-stage transmission focus A scanning method in an ultrasonic diagnostic apparatus, characterized by repeating scanning. 2. A scanning line within a predetermined range from the axis of symmetry of the scanning region is scanned by performing multi-stage transmission focus from the scanning line on the axis of symmetry, and then located at a bilaterally symmetrical position from the axis of symmetry. For multiple pairs of scan lines, gradually scan toward the opposite ends of the scan area on one of the pair of scan lines to perform multi-stage transmission focus, and then perform scan on the other scan line to perform multi-stage transmission focus. For a plurality of pairs of scanning lines that are outside the predetermined range and are located in a substantially symmetrical position, scanning is performed toward the scanning lines at both ends from the scanning line closest to the axis of symmetry, and the scanning lines at both ends of the scanning region are scanned. The scanning method in the ultrasonic diagnostic apparatus according to claim 1, wherein scanning is completed. 3. An ultrasonic diagnostic apparatus for performing multi-stage ultrasonic beam focusing on each scanning line of a scanning region having a plurality of scanning lines to acquire data, wherein the scanning line is out of a predetermined range from a symmetry axis of the scanning region. With respect to a plurality of pairs of scanning lines at symmetrical positions, multistage transmission focus scanning is repeated while alternately scanning one pair of prescribed scanning lines, and then within a prescribed range from the axis of symmetry described above, and substantially symmetrical. For a plurality of scanning lines in the position, scanning is performed by multi-stage transmission focus from a predetermined scanning line in the above range, and multi-stage transmission focus scanning is repeated for other scanning lines in the above range to obtain a plurality of scanning lines in the range. A scanning method in an ultrasonic diagnostic apparatus, which comprises scanning a scanning line. 4. A plurality of pairs of scanning lines, which are outside a predetermined range from the axis of symmetry of the scanning area and are in a substantially left-right symmetrical position, are scanned from the scanning lines located at both ends of the scanning area, and gradually move toward the axis of symmetry. Scanning is performed toward the scanning line, and scanning lines within a predetermined range from the symmetry axis of the scanning region are scanned from the scanning lines closest to both ends, and the scanning lines on the symmetry axis are subjected to multistage transmission focus to complete scanning. The scanning method in the ultrasonic diagnostic apparatus according to claim 3, wherein: