JPS61244336A - 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] The present invention relates to an ultrasonic diagnostic apparatus that makes it possible to prevent image quality deterioration of an ultrasonic image due to the first side lobe of an ultrasonic beam.

[Technical background of the invention and its problems] One of the basic techniques for constructing ultrasonic diagnostic images 81 of the heart, etc. is to scan an ultrasonic beam in a fan shape between the ribs in order to suppress the influence of reflection from the ribs. The so-called sector scan method is well known and extremely common.

Among these sector scan methods, there is a mechanical sector scan method that composes an ultrasound image by mechanically driving an ultrasound transducer, and a sector scan method that enables fan-shaped scanning by driving the ultrasound transducer according to the driving method of a phased array antenna. Although there is an electronic sector scanning method, the latter is superior to the former in terms of reliability of each component of the ultrasound probe.

However, in the case of the electronic sector scan method, if the scanning angle, that is, the sector angle is made large, the height of the main lobe, which is originally important in the ultrasonic beam, decreases, leading to a deterioration of the S/N ratio, or conversely, increasing the sector angle The lobe increases, this first side lobe increases, and this first side lobe catches the reflector and forms a false image.

This situation will be explained with reference to FIGS. 3 and 4.

FIG. 3 shows the point light source transfer function a<r> when the sector angle is zero, that is, when the ultrahigh wave beam is radiated in the vertical direction from the array surface of the ultrasonic transducers.

This point light source transfer function Q(f) is used in the optical field, but it can also be applied to analyze the propagation of ultrasound waves. Assuming that a, the interval between each vibrator is b, and the number of simultaneously driven vibrators is C, the point light source transfer function G(') can be defined by the following equation (1).

G(f)=ac[5inc(at)rn(bf
]X5inc cf...(1) Here, 5inc af and 5inc at are sink functions, and rn(bf) is a sach function that can be defined when a delta function repeats at regular intervals. Further, f is the frequency of the ultrasonic wave. It is clear from FIG. 3 that the height of the central main lobe is overwhelmingly larger than the height of the first side lobes Q on both sides thereof.

On the other hand, Fig. 4 shows the point light source transfer function G-(f) when the ultrasonic beam is emitted in the direction of the sector angle θ, and in this case, the main lobe I moves from the center O to
It is shifted by fs shown in the formula.

r s =s in θ/λ
...(1) Here, λ is the wavelength of the ultrasonic wave.

Comparing the heights of the main lobe m and the first side lobe g shown in FIGS. 3 and 4, it can be seen that as the sector angle θ increases, the height of the main lobe va (D decreases,
The height of increases. For this reason, in conventional ultrasonic diagnostic equipment that uniformly regulates the maximum sector angle, S/S/ In particular, when using the ultrasonic blow 7 for sector scanning, the above-mentioned width a is not only unbalanced in image quality on the display screen due to deterioration of the N ratio, but also to form a false image due to the first side lobe. , the coarse distance and the number of simultaneously driven transducers C are set, but the maximum sector angle is not determined for each ultrasound probe, but is uniformly regulated by the ultrasound diagnostic equipment itself. Therefore, when changing the ultrasonic probe depending on various conditions such as the purpose of diagnosis and the site to be diagnosed, there is a problem that depending on the newly used ultrasonic probe, the image quality may deteriorate as described above.

Incidentally, this problem applies not only to ultrasonic probes for sector scans but also to ultrasonic probes for trapezoidal scans and convex scans.

[Object of the Invention] The present invention has been made in view of the above circumstances, and can automatically and appropriately set and control the maximum sector angle according to the ultrasonic waveform used, thereby reducing image quality deterioration. The object of the present invention is to provide an ultrasonic diagnostic apparatus that does not cause such problems.

[Summary of the Invention] The outline of the present invention for achieving the above object is to provide an ultrasonic probe having an array of transducers, transmit and receive ultrasound under predetermined transmission and reception conditions, and display an ultrasound image on a display unit. In the ultrasonic diagnostic apparatus obtained above, there is provided a storage means for storing probe information consisting of one width interval of transducers of the ultrasonic probe and the number of simultaneously driven transducers; The present invention is characterized by comprising calculation control means for correcting the maximum sector angle and the number of scanning lines for setting the display range on the display unit, and controlling the transmission and reception conditions based on the results of these calculations.

[Embodiments of the Invention] Examples of the present invention will be described below. First, the outline of the embodiment device shown in FIG. 1 will be explained. This device has a timing generator 11 that controls the entire system, and this timing generator 11 drives an ultrasonic transmission/reception control section 10.

The superhigh wave transmission/reception control section 10 first operates the transmission delay control section 5 and also activates the pulser 4 to which high voltage is applied from the ultrasonic voltage source 3.

As a result, the ultrasonic probe 1 is
An excitation signal is sent to the ultrasonic probe 1, and ultrasonic waves are emitted from the transducer of the ultrasonic probe 1 toward the subject with a predetermined delay applied by the transmission delay control section 5.

The ultrasonic waves reflected by the object are
The signal enters the Fz i11 element, where it is converted into an echo signal, which is an electrical signal, and sent to the preamplifier section 6 via the high voltage switch section 2, which is switched to the reception state, where it is amplified to a predetermined level. Then, this echo signal is subjected to delay processing corresponding to the transmission delay control section 5 in the reception delay control section 7 at the next stage, phasing and adjustment by the adder 8, signal processing by the reception circuit 9, and then sent to the digital scan converter 12. and is further displayed as an ultrasound image by the display unit 13.

In FIG. 1, 14 is an operation panel, and this operation panel 14 sends various control signals to the ultrasonic transmission/reception control unit 10, and also sends out main lobe tolerances set in advance to the calculation control means 50, which will be described later. The decrease IO and the allowable increase (10) of the first sidelobe are sent out by key operation.

Next, the main parts of the apparatus of this embodiment will be explained in detail. In addition to the bin group required for normal ultrasound transmission and reception between the ultrasound probe 1 and the main body of the ultrasound diagnostic apparatus, the device of this embodiment has the width a1 interval of the transducers in the ultrasound probe 1, and the number of simultaneously driven transducers. A connector section 101 also includes a group of bins as a storage means for recording probe information consisting of C, and the connector section 10
1 inputs the probe information, determines the maximum sector angle θmax based on the point light source transfer function described above, calculates the number of scanning lines that determines the display range based on this maximum sector angle θn+ax, and transmits the transmission delay controller 5 and The calculation control means 50 controls the reception delay control section 7.

This calculation control means 50 inputs probe information consisting of the transducer width a3 interval and the number C of simultaneously driven transducers from the connector section 101, and based on these values, calculates the probe information in the vertical direction (θ= Vertical main lobe calculation unit 102 and vertical first side lobe calculation unit 103 as first calculation means for calculating the heights of the main lobe and first side lobe of the point light source transfer function when ultrasonic waves are radiated to O). Then, the probe information consisting of the width a1 interval and the number C of simultaneously driven transducers is input, and the sector angle θ is determined from the transducer array surface based on these values and the sector angle θ set by the maximum sector angle determination unit 111, which will be described later. θ main lobe calculation unit 107 and θ first side lobe calculation unit 108 as second calculation means for calculating the heights of the main lobe and first side lobe after emitting ultrasonic waves, and the vertical main lobe calculation unit a mouth reducer 104 which inputs the output in decibels from the unit 102 and the allowable decrease IQ of the main lobe from the operation panel 14 and calculates the allowable minimum main lobe value based on these; and the first vertical side row 1103. an adder 105 that inputs the output in decibels and the allowable increase aO of the first sidelobe from the operation panel 14 and uses these to calculate the allowable maximum first sidelobe value; Main lobe value and the θ main lobe ff
A first comparator 106 that compares the main lobe value at the sector angle θ from the t0 aircraft 107 and determines whether or not this main lobe value is within the allowable range; a second comparator 109 that compares the side lobe value with the first side lobe value at the sector angle θ from the θ first side lobe calculation unit 108 and determines whether the first side lobe value is within an allowable range; and the first
．． Goo 1-Circuit 1 that opens when at least one of the judgment results of the second comparator 106 and 109 is out of the allowable range
10, the sector angle θ is increased in predetermined steps in order to calculate the maximum sector angle θWaX, and each time the θ main lobe calculation unit 107 and the θ first side O-b calculation unit 10
8 and stops increasing the sector angle θ when the gate circuit 110 is opened, and sets the sector angle one step before that time as the maximum sector angle θIaX and sends this value; Based on the output of the maximum sector angle determination section 111, the display range on the display section 13 is determined, the number of scan lines is set to 1, the calculation result is stored, and the transmission delay control section 5 and the reception delay control section 7 A display scanning control section 112 is provided to control the display scanning control section 112.

The connector section 101 serving as rYJ storage means consists of a plug GNP and a receptacle CNR as shown in FIGS. 2(a) and 2(b), and the plug GNP is connected to the ultrasound probe 1 side, that is, the cable side. The receptacle CNR is attached to the casing of the ultrasonic diagnostic apparatus.

In the same figures (a) and (b), the numbers ■ to ■ represent bins that are arranged in correspondence with each other, and these bins are spaced apart by the width a1 of the transducers and from the number of simultaneous drive #JJ transducers C. It is used to store probe information. One terminal of each of the resistors R2 to Rn-1 is connected to each of the second to n-1th bins of the plug GNP, and the other terminal of each of the resistors R2 to Rn-1 is connected to the second to n-1th bins of the plug GNP. is also connected to the first bin ■. Also,
Bin ■ and Bin ■ are connected to Bin n.

On the other hand, +V volt is applied to the pin (2) of the receptacle CNR, and the bottle (2) is grounded.

The connector section 101 having such a configuration has a plug C.
By coupling NP to the receptacle GNP, the bins with the same number are electrically connected to each other, and as a result, the voltage of -V volts is applied to the plug CN through each resistor R2 to Rn-1.
It is added to the R-side bins ~ ([EE).

Therefore, the bin ■ connected to the ground level bin n,
It is detected by checking each bin (2) to (ζ) on the receptacle CNR side that only (2) is at the ground level, and thereby the probe information can be stored.

Next, the operation of the device having the above configuration will be explained, focusing on the operations of the connector section 101 and the calculation control means 50.

First, when the ultrasonic probe 1 with the plug GNP and cable is connected to the receptacle CNR attached to the casing of the ultrasonic diagnostic device, the probe information of the width a9 interval and the number of simultaneously driven transducers C is transmitted to the ultrasonic wave. It is recognized by the IWi neck wear body. In the connector section 101 shown in FIGS. 2(a) and 2(b), only the bins ■ and ■ are at the ground level, and the other bins are at the 4■ volt level. It is assumed that the voltage level pattern is associated with the voltage level pattern.

The vertical main lobe calculation unit 102 and the vertical first side lobe calculation unit 103 of the calculation control means 50 calculate the main lobe and first side of the ultrasound when the sector angle θ=0 based on the point light source transfer function according to the probe information. The height of the lobe is calculated, and the respective calculation results are sent to a subtracter 104 and an adder 105 in decibels.

The subtracter 104 inputs the main lobe value in decibels and its allowable decrease IQ, calculates the allowable minimum main lobe value, and sends it to the first comparator 106 . Further, the adder 105 inputs the value of the first sidelobe in decibels and its allowable increase amount 00, determines the maximum allowable first sidelobe value, and sends this to the second comparator 109 .

On the other hand, the maximum sector angle determination unit 111 sets the sector angle in predetermined steps and calculates the sector angle each time by the θ main lobe calculation unit 111.
01 and θ are sent to the first sidelobe calculation unit 108.

The θ main lobe calculation unit 107 and the θ first side lobe calculation unit 108 each input the probe information and the set sector angle, and calculate the main lobe value and the second side lobe value at the sector angle based on the point light source transfer function. 1 sidelobe values and sends these results to a first comparator 106 and a second comparator 109, respectively.

The first comparator 106 compares the minimum allowable main lobe value with the main lobe value at the set sector angle and determines whether this main lobe value is within the allowable range. The second comparator 109 similarly compares the allowable maximum first sidelobe value with the first sidelobe value at the set sector angle, and determines whether this first sidelobe value is within the allowable range. do.

The gate circuit 110 keeps the gate off when it is determined that the determination results of the first comparator 106 and the second comparator 109 are both within the allowable range, and as a result, the maximum sector angle determination unit 111 sets the sector angle for the next step and calculates the θ main lobe calculation unit 10 in the same manner as described above.
7 and θ first side O-branch π1 calculation unit 108 is driven.

On the other hand, if the first and second comparators 106 and 109 determine that at least one of the main lobe value and the first side lobe value exceeds the allowable range, the gate circuit 110
opens and sends an instruction to the maximum sector angle determination unit 111 to stop further increase in the sector angle.

The maximum sector angle determination unit 111 determines the sector angle of the previous step based on the instruction from the gate circuit 110 as the maximum sector angle θl1.
The value is sent to the display scanning control unit 112 as lax. The display operation control unit 112 determines the transmission and reception conditions of the number of scanning lines that determine the delay time and display range of the transmission delay control unit 5 and reception delay control unit 7 based on the maximum sector angle θ + nax, stores this result, and , and controls the transmission delay control section 5 and the reception delay control section 7 based on this result.

Through the above operations, although the maximum sector angle θmax may increase or decrease depending on the type of ultrasound probe used for transmitting and receiving ultrasound, the S/N ratio may deteriorate in areas with large sector angles on the display unit 13, and the first side Virtual image formation due to lobes can be suppressed.

The present invention is not limited to the embodiment shown in I: iL, and various modifications can be made within the scope of the gist thereof.

For example, if the maximum sector angle θlaX exceeds 90',
Since most regions of interest are within a sector angle of 90°, the maximum sector angle determination unit 111 stops increasing the sector angle at 90″, and the maximum sector angle θn+ax=90.
' may also be used.

In addition, in the above-mentioned embodiment, even in the vertical direction of ultrasonic radiation,
For ultrasonic emission when the sector angle is θ, we assumed a point light source transfer function and calculated the heights of the main lobe and first side lobe based on the point light source transfer function. In this case, since the light source becomes a pulsed point light source, a certain amount of correction is required, but this can be adequately addressed by empirical modification of the point light source transfer function.

[Effects of the Invention] According to the present invention described in detail above, although the display range differs depending on the type of ultrasonic probe, it is possible to prevent deterioration of the S/N ratio at the edge where the sector angle is large, and to It is possible to provide an ultrasonic diagnostic apparatus that can prevent the formation of a virtual image due to an increase in one sidelobe.

In addition, unlike conventional devices, the maximum sector angle can be set to, for example, 9.
Compared to those that are regulated to 0°, even if the maximum sector angle is small, the frame frequency (frequency that indicates how many screens can be displayed per hour) can be increased accordingly,
It is possible to provide an ultrasonic diagnostic apparatus that can contribute to more accurate understanding of the dynamics of a subject.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment device of the present invention;
Figures 2 (a) and (b) are schematic circuit diagrams showing the state of the bin connection of the connector part of the same device, and Figure 3 shows the case where ultrasonic waves are emitted vertically from the transducer array surface of the ultrasound probe. FIG. 4 is a waveform diagram showing a point light source transfer function when ultra-8 waves are emitted from the transducer array surface at a sector angle θ of 6. 1... Ultrasonic bulb O-bu, 13... Display section, 50...
- Calculation control section, 101... Connector section, 111...
112: Display scanning control section. Agent Patent attorney Kensuke Chika (and 1 other person) Figure 2

Claims (4)

[Claims] (1) In an ultrasonic diagnostic apparatus that is equipped with an ultrasonic probe having an array of transducers and transmits and receives ultrasonic waves under predetermined transmission and reception conditions to obtain an ultrasonic image on a display section, the ultrasonic a storage means for storing probe information including the width and spacing of the transducers of the probe and the number of simultaneously driven transducers; and a scanning line for setting the maximum sector angle of the ultrasonic probe and the display range on the display unit based on the probe information. An ultrasonic diagnostic apparatus characterized by comprising: calculation control means for calculating numbers and controlling the transmission/reception conditions based on the results of these calculations. (2) The storage means includes means for storing probe information in a plug connected to the ultrasound probe side of the connector section provided between the ultrasound probe and the main body of the ultrasound diagnostic apparatus. An ultrasonic diagnostic apparatus according to claim 1. (3) Based on the probe information, the calculation control means performs point light source transmission when ultrasonic waves are emitted in a direction perpendicular to the array surface of the transducers and when ultrasonic waves are emitted at a certain angle from the array surface. The main lobe and the first
First and second calculation means for calculating the height of the side lobe, and each decrease and increase of each main lobe and each first side lobe calculated by the first and second calculation means are calculated by a predetermined amount. A patent claim comprising: a maximum sector angle determination unit that sets the maximum sector angle by the ultrasonic probe within a range that is equal to or less than a value; and a display scanning control unit that calculates the number of display scanning lines on the display unit based on this maximum sector angle. The ultrasonic diagnostic device according to scope 1 or 2. (4) The calculation control means has a function of timing transmission and reception of ultrasound so that the ultrasound beam is scanned within the range of the maximum sector angle set by the maximum sector angle determination unit, and storing the calculation results. An ultrasonic diagnostic apparatus according to any one of claims 1 to 3, having a display control section comprising: