JPH0956715A - Ultrasonic diagnosing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the diagnostic sensitivity by regulating receiving gain at a specific position in scanning space according to an angle formed by a vector direction of set at a specific position and a vector direction of ultrasonic beam passing the specific position. SOLUTION: High frequency pulse generated from a transmitter is given to each oscillator of a prove 1 and the ultrasonic pulse is injected to a subject. Reflected waves from the subject are received by the prove 1, are taken in a receiver 8, and when image data is put in a sensitivity corrector 11 through an A/D converter and a digital scanning converter(DSC) 10, sensitivity correcting treatment is conducted concerning the direction perpendicular to the ultrasonic beam. Namely, the receiving gain at a specific position is regulated according to the angle formed by a given vector direction set at the specific position in the scanning space and the vector direction of ultrasonic beam passing through the specific position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus that obtains internal information of a subject by transmitting and receiving ultrasonic waves to the subject.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus receives an ultrasonic beam generated from a probe into a subject, receives a reflected wave signal returned from the inside, and processes the obtained electrical signal. The internal information of the subject is imaged by.
By its nature, ultrasonic waves are attenuated by diffusion, absorption and scattering. Therefore, the sensitivity becomes poor in the deep part of the subject where the propagation time of the ultrasonic beam becomes long. In order to avoid this, in general, the sensitivity is increased with the passage of time from the transmission, that is, the so-called TGC (Time Gain Control) technique of increasing the reception gain for a reflected wave from a deeper place, or according to the magnitude of the reception signal. AGC (Automatic Ga) that changes sensitivity
in Control) technology is used. These sensitivity corrections are in the direction parallel to the ultrasonic beam.

On the other hand, since the ultrasonic diagnostic apparatus uses the reflected wave of the ultrasonic beam, the sensitivity is theoretically poor in the direction perpendicular to the ultrasonic beam, and the sensitivity is corrected accordingly. There wasn't. Therefore, as shown in FIG. 14, depending on the subject, the sensitivity in the direction perpendicular to the ultrasonic beam is poor and the image “dropout” occurs, which adversely affects the diagnosis. For example, when diagnosing a heart disease using an ultrasonic diagnostic apparatus, there is a problem that the contour of the heart cannot be accurately grasped.

[0004]

As described above, in the conventional ultrasonic diagnostic apparatus, in view of the principle that an image is formed by using the reflection of the ultrasonic beam from the subject, the ultrasonic beam is perpendicular to the ultrasonic beam. There is a problem that the sensitivity in the direction is poor, and in some cases, "missing" of the image occurs.

In view of the above points, an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of performing more accurate diagnosis by performing sensitivity correction in the direction perpendicular to the ultrasonic beam. And

[0006]

SUMMARY OF THE INVENTION The present invention is an ultrasonic diagnostic apparatus for obtaining internal information of an object by transmitting and receiving ultrasonic waves to and from the object, a scanning space for scanning the beam of the ultrasonic wave. The reception gain at a specific position in the inside is adjusted according to an angle formed by a predetermined vector direction set at the specific position and a vector direction of the beam of the ultrasonic wave passing through the specific position. To do.

Further, according to the present invention, in an ultrasonic diagnostic apparatus for obtaining internal information of the subject by transmitting and receiving ultrasonic waves to the subject, a specific position in a scanning space for scanning the beam of the ultrasonic wave. The brightness of the image in is corrected according to the angle formed by the predetermined vector direction set at the specific position and the vector direction of the ultrasonic beam passing through the specific position.

In the present invention, the reception gain or the image brightness at the specific position is adjusted according to the angle formed by the predetermined vector direction set at the specific position and the vector direction of the ultrasonic beam passing through the specific position. Be corrected or corrected. Therefore, sensitivity correction can be performed in the direction perpendicular to the ultrasonic beam, and more accurate diagnosis can be performed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) In the first embodiment, sensitivity correction in the direction perpendicular to the ultrasonic beam is performed at the image level. FIG. 1 shows a block diagram of an ultrasonic diagnostic apparatus according to the first embodiment. This ultrasonic diagnostic apparatus is compatible with the pulse echo type of the sector electronic scanning system. Of course, another scanning method such as linear or convex, or a mechanical scanning method may be used. Probe 1
Is equipped with a transducer array at its tip. The transducer array is an array in which a plurality of transducers are arranged in a line. The high frequency pulse generated from the oscillator 2 is applied to each transducer of the probe 1. Thereby, the ultrasonic pulse is incident on the subject. The reflected wave reflected at the boundary of the acoustic impedance inside the subject is received by the probe 1 and taken into the receiver 8 as an electric signal (hereinafter referred to as an echo signal).

The receiver 8 comprises a reception delay circuit 3, an adder 4, a high frequency amplifier 5, a logarithmic amplifier 6 and a detector 7. The echo delay signal is given a delay time for each channel by the reception delay circuit 3 and added by the adder 4. As a result, an echo signal in which a specific direction component is emphasized is obtained. This echo signal is amplified by the high frequency amplifier 5, and then its dynamic range is changed by the logarithmic amplifier 6.
The amplitude information of the echo signal whose dynamic range has been changed by the logarithmic amplifier 6 is extracted by the wave detector 7. A signal including this amplitude information is hereinafter referred to as an echo amplitude signal.

The gain controller 14 controls the gain of the high frequency amplifier 5 based on the echo amplitude signal output from the detector 7 in order to correct the sensitivity nonuniformity due to the attenuation of the ultrasonic waves. This gain control is a technique known as so-called TGC (Time Gain Control) in which the gain is increased with the lapse of time from transmission, that is, the echo signal from a deeper place is increased in gain.

The echo amplitude signal output from the detector 7 of the receiver 8 is digitized by the A / D converter 9 and input to a digital scan converter (hereinafter abbreviated as DSC) 10 as echo amplitude data. . DSC
Reference numeral 10 performs scanning line conversion processing, interpolation processing, and the like in order to convert the echo amplitude data into image data.

The image data output from the DSC 10 is
The sensitivity corrector 11 provides sensitivity correction processing in the direction perpendicular to the ultrasonic beam. The sensitivity-corrected image data is converted into an analog signal by the D / A converter 12 and sent to the display 13 as a video signal, and visually displayed as a tissue tomographic image (image in B mode) on the display 13 in grayscale.

FIG. 2 shows a block diagram of the sensitivity corrector 11. The image data output from the DSC 10 is sent to the brightness correction unit 11-3 via the reference point setting unit 11-1 and the vector angle calculation unit 11-2 in this order. Reference point setting unit 11-1
Sets a reference point, such as a center point in the heart chamber, in the scanning plane of the ultrasonic beam. As this reference point,
There is no particular limitation, and for example, it may be a barycentric point of the contour shape of the heart wall, or a point arbitrarily set by the operator. The vector angle calculation unit 11-2 sets each of a plurality of pixels in the scanning plane as a target point P, a vector direction (PC) from the target point P to the reference point C, and an ultrasonic beam (ultrasonic beam) where the target point P exists. An angle (vector angle) θ formed by the sound wave scanning line; OP) is calculated. The brightness correction unit 11-3 performs sensitivity correction (brightness correction) on each pixel value (brightness) of the image data based on the vector angle θ of the point calculated by the vector angle calculation unit 11-2.

Next, the function of sensitivity correction will be described. FIG. 3 is a supplementary diagram of this description. In the figure, O is the incident position of the ultrasonic beam (position of the ultrasonic probe 1), P is the target point, C
Indicates the reference points. Vector angle calculator 11
At -2, the vector angle θ between the direction of the vector from the target point P to the reference point C and the direction of the vector of the ultrasonic beam in which the target point P exists is calculated. Based on this vector angle θ, the brightness correction unit 11-3 performs brightness correction on the pixel value of the target point P. The calculation of the vector angle θ and the brightness correction based on the vector angle θ are performed for all pixels in the scanning plane by the ultrasonic beam.

Next, the brightness correction by the brightness correction unit 11-3 will be described in detail below. I (x, y) is the pixel value (luminance) before luminance correction of the target point P at coordinates (x, y), I ′ (x, y) is the pixel value (luminance) after luminance correction, and , y) is the brightness correction amount Fi (x, y), I '(x, y) is given by the equation (1). I ′ (x, y) = fi (θ, I (x, y)) (1) The brightness correction function fi (θ) for changing the brightness correction amount according to θ is as shown in FIG. In addition, as long as θ has a maximum value at 90 ° and θ has a minimum value at 0 ° and 180 °, any function whose value (brightness correction intensity) changes according to θ may be used. For example, (1 Equation (2) is given as Equation (2). In the equation (2), A and B are constants.
Note that θ changes within the range of 0 ° ≦ θ ≦ 180 °. I ′ (x, y) = A × (1 + B × sin (θ)) × I (x, y) (2) Further, the formula (3) may be adopted. Note that in the equation (3), A and B are constants.

I ′ (x, y) = A × (1 + B × exp (− | θ−90 ° |)) × I ′ (x, y) (3) The brightness correction function fi (θ) is shown in FIG. Any function may be used as long as the intensity of the brightness correction changes according to θ as shown. Further, in FIG. 4, the maximum value and the minimum value of fi (θ) do not have to be constant values. That is, it is not always necessary to satisfy fi (0 °) = fi (180 °).

As described above, according to the first embodiment, the sensitivity in the vicinity of the direction perpendicular to the ultrasonic beam (in this case, θ = 90 °) is improved. Moreover, the part where the sensitivity is originally good (θ
(0 °, θ = 180 °), luminance correction is hardly performed, and therefore an image is easy to see with less noise due to excessive sensitivity correction.

(Second Embodiment) In the second embodiment, sensitivity correction in the direction perpendicular to the ultrasonic beam is achieved by gain control of the echo signal. FIG. 5 shows a block diagram of the ultrasonic diagnostic apparatus according to the second embodiment. 5, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

The image data output from the DSC 10 is supplied to the correction signal generator 15. Correction signal generator 15
Supplies a correction signal that changes according to the vector angle θ to the gain controller 14, as in the first embodiment. The gain controller 14 controls the gain of the high frequency amplifier 5 according to the correction signal from the correction signal generator 15. This achieves sensitivity correction in the direction perpendicular to the ultrasonic beam.

FIG. 6 shows a block diagram of the correction signal generator 15. The image data output from the DSC 10 is sent to the vector angle calculation unit 15-2 via the reference point setting unit 15-1. The reference point setting unit 15-1 sets a reference point such as a center point in the heart chamber on the scanning plane by the ultrasonic beam. The reference point is not particularly limited, and may be, for example, the center of gravity of the contour shape of the heart wall, or a point arbitrarily set by the operator. Vector angle calculator 15
-2 calculates a vector angle θ between the line segment connecting the reference point and the target point and the ultrasonic beam where the target point exists, with each of the plurality of pixels in the scanning plane as the target point. Correction amount calculation unit 1
5-3 calculates the gain correction amount of the target point based on the angle θ calculated by the vector angle calculation unit 15-2. The coordinate conversion unit 15-4 converts the coordinates of the target point expressed by (x, y) into the coordinates on the ultrasonic beam expressed by (scanning angle, depth). The converted coordinates and information on the gain correction amount are supplied from the correction signal generator 15 to the gain controller 14 as a correction signal.

The gain controller 14 obtains the gain of the high frequency amplifier 5 based on the echo amplitude signal output from the detector 7 in order to correct the sensitivity nonuniformity due to the attenuation of the ultrasonic wave.
Further, the obtained gain is corrected based on the gain correction amount from the correction signal generator 15, and the high frequency amplifier 5 is controlled so that amplification of the echo signal is realized with the corrected gain.

Next, the function of sensitivity correction will be described.
Similar to the case of the first embodiment, the reference point setting unit 15-
A reference point is set at 1. Then, the vector angle calculation unit 1
At 5-2, a vector angle θ between the direction of the vector from the target point toward the reference point and the direction of the vector of the ultrasonic beam in which the target point exists is calculated. Based on this vector angle θ, the correction amount calculation unit 15-3 calculates the correction amount of the gain of the gain controller 14 with respect to the echo signal regarding the target point. The information on the correction amount is supplied to the gain controller 14 as a correction signal together with the coordinate information represented by (scanning angle (a), depth (d)) obtained by the coordinate conversion unit 15-4.

The correction amount calculator 15-3 calculates the gain correction amount according to the equation (4). Let S (x, y) be the gain at the position (x, y) on the image, S '(x, y) be the gain after correction, and fg (θ, S (x, y)) be the gain correction function.

S ′ (x, y) = fg (θ, S (x, y)) (4) A gain correction function fg for changing the gain according to the vector angle θ is as shown in FIG. In addition, the function may be such that the gain changes in accordance with the vector angle θ so that θ has a maximum value at 90 ° and θ has a minimum value at 0 ° and 180 °. ) Expression is given as Expression (5). In the equation (5), A and B are constants. Note that θ changes within the range of 0 ° ≦ θ ≦ 180 °. Further, the formula (6) may be adopted. In the equation (6), A and B are constants.

S ′ (x, y) = A × (1 + B × exp (− | θ−90 ° |)) × S (x, y) (6) As the gain correction amount function fg, the above-mentioned (5 ) Expression, (6)
The function is not limited to the formula, and as shown in FIG. 7, another function may be adopted as long as the corrected gain changes according to the vector angle θ. Further, in FIG. 7, the maximum value and the minimum value of the corrected gain do not have to be constant values. That is, it is not always necessary to satisfy S '(0 °) = S' (180 °).

Next, in the coordinate conversion unit 15-4, the coordinates (x, y) on the image are the coordinates (scanning angle a) on the ultrasonic beam.
, Depth d). The information on the gain correction amount and the position is supplied to the gain controller 14. Gain controller 1
In 4, the gain of the high frequency amplifier 5 is obtained based on the echo amplitude signal output from the detector 7 in order to correct the sensitivity nonuniformity due to the attenuation of the ultrasonic wave, and the obtained gain is obtained from the correction signal generator 15. The gain is corrected according to the vector angle θ based on the gain correction amount and the high frequency amplifier 5 is controlled so that the echo signal is amplified by the corrected gain.

By changing the gain according to the vector angle θ as described above, the sensitivity in the direction perpendicular to the ultrasonic beam is improved. Moreover, since the gain is not excessively increased in the direction parallel to the sensitive ultrasonic beam, noise does not increase.

In the second embodiment, the sensitivity correction is performed by controlling the gain of the echo signal. However, by controlling the gain of the echo amplitude signal after detection,
The sensitivity may be corrected. As shown in FIG. 8, an amplitude controller 16 is added between the A / D converter 9 and the DSC 10, and an echo amplitude signal is generated by the amplitude controller 16 based on the correction signal from the correction signal generator 15. It is realized by changing the amplitude of. Further, the correction signal generator 15 is arranged after the DSC 10, calculates the correction amount at the coordinates (x, y), and sends the correction signal to the gain controller 14 in FIG. 5 or the amplitude controller 16 in FIG. DSC1
The correction signal generator 15 in this case may be disposed before 0, and the coordinate conversion unit 15-4 is not necessary in the configuration of the correction signal generator 15, and the coordinates (scanning angle, depth) of the ultrasonic beam are used. (Third Embodiment) In the third embodiment, the sensitivity correction in the direction perpendicular to the ultrasonic beam is executed only for the area outside the arbitrary shape U in the scanning plane. The configuration thereof may be either of FIG. 1 or FIG. 5, and here, FIG. 1 will be described as an example.

The arbitrary shape U is set manually as an outline of the heart, for example, by an operator through a console (not shown) or automatically by an outline trace. The reference point C is set in the arbitrary shape U in the scanning plane by the reference point setting amount 11-1. Vector angle calculator 11-
2, the target points P1, P2 of the area outside the arbitrary shape U are
, Q1, Q2, ... For each of the vector angles θ (P
1), θ (P2), ..., θ (Q1), θ (Q2) ,. The vector angle θ in this case is a vector direction connecting the reference point C and a point (points P1 and Q1 in FIG. 9) on the outer edge of the arbitrary shape U, and each target point (P1, P1) on the vector.
2, P3, Q1, Q2, Q3) and the direction of the vector of each ultrasonic beam. In the brightness correction unit 11-3, brightness correction is performed based on the vector angle of each target point.

By limiting the sensitivity correction only to the outer region of the arbitrary shape as described above, the processing time is shortened, and in the diagnosis of the heart, the arbitrary shape U is set as the arbitrary shape U in the vicinity of the contour of the heart wall. By installing a shape similar to the contour, it is possible to emphasize only the part of the heart wall that is necessary when diagnosing the dynamics of the heart wall, so that a more accurate diagnosis can be made.

In the present embodiment, the sensitivity correction is carried out for the area outside the arbitrary shape U, but the sensitivity correction may be carried out only for the points on the outer edge of the arbitrary shape or for the neighboring areas. (Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the vector angle is calculated without using the reference point and the sensitivity is corrected, and the configuration thereof may be either FIG. 1 or FIG. However, the sensitivity corrector 11 of FIG. 1 has the configuration of FIG. 10A, and the correction signal generator 15 of FIG.
The configuration of (b) is adopted.

FIG. 11 is an explanatory diagram of a method of calculating a vector angle without using a reference point. Perpendicular vector calculation unit 11-4
(Or 15-5) obtains a perpendicular line Pt that passes through the target point P on the outer edge of the arbitrary shape U and is perpendicular to the contour of the arbitrary shape U. The vector angle calculation unit 11-2 (or 15-2) obtains a vector angle θ between the perpendicular Pt and the vector OP of the ultrasonic beam passing through the target point P. The brightness correction unit 11-3 performs brightness correction (sensitivity correction) on the image data based on the vector angle θ. In addition, the correction calculation unit 15-3
Calculates the gain correction amount based on the vector angle θ.

Further, as in the third embodiment, the sensitivity correction may be performed in the entire area outside the arbitrary shape U in the present embodiment, or the sensitivity correction may be performed only in the area near the arbitrary shape U. It doesn't matter.

The present invention is not limited to the above-mentioned embodiment, but can be modified in various ways. For example, in the above description, the calculation of the vector angle and the calculation of the sensitivity correction amount are performed for each pixel, but as shown in FIG. 12, for a plurality of pixels having a close vector angle, one of them is selected. The vector angle may be calculated for each pixel, the sensitivity correction amount may be calculated, and the pixel may be used for another pixel. FIG. 12 shows FIG.
FIG. 7 is a diagram in the case of performing sensitivity correction using a vector angle between a perpendicular line at a target point P1 on an arbitrary shape U and the vector direction of an ultrasonic beam, similarly to FIG. In FIG. 12, an arbitrary shape U
The point on the perpendicular Pt at the target point P1 on the contour of
P5. P1 to P5 are set as one area, and the vector direction of the ultrasonic beam at this time is calculated by using the vector OP3 of the ultrasonic beam passing through the target point P3. The sensitivity correction according to this θ is performed on the target points P1 to P5. That is, in this case, all the areas P1 to P5 have the same correction value. By doing so, the amount of calculation can be reduced and the processing time can be shortened.

In the above embodiment, the reference points in the sensitivity corrector 15 and the correction signal generator 16 may be set automatically, or may be manually specified by the user. But it's okay.

Further, in the above embodiment, the sensitivity correction of the present invention is performed inside the ultrasonic diagnostic apparatus.
The above sensitivity correction may be performed by sending an output signal from the ultrasonic diagnostic apparatus to the sensitivity correction apparatus 17 as shown in FIG. 13 outside the ultrasonic diagnostic apparatus. In this case, the data input to the sensitivity correction device 17 may be performed by once recording the output from the ultrasonic diagnostic device on some recording medium and reading the data. Also, FIG.
In 3, the sensitivity correction device 17 is provided with a display, but it is not always necessary and the output of the sensitivity correction device 17 may be sent to the ultrasonic diagnostic apparatus and displayed on the device side.

[0038]

According to the present invention, the reception gain or the image brightness at a specific position depends on the angle formed by the predetermined vector direction set at the specific position and the vector direction of the ultrasonic beam passing through the specific position. Adjusted or corrected. Therefore, sensitivity correction can be performed in the direction perpendicular to the ultrasonic beam, and more accurate diagnosis can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to a first embodiment.

FIG. 2 is a block diagram of a sensitivity correction unit shown in FIG.

FIG. 3 is an explanatory diagram of a vector angle calculation method.

FIG. 4 is a diagram showing an example of a brightness correction function.

FIG. 5 is a block diagram of an ultrasonic diagnostic apparatus according to a second embodiment.

6 is a block diagram of a correction signal generator in FIG.

FIG. 7 is a diagram showing an example of a gain correction function.

FIG. 8 is a block diagram of an ultrasonic diagnostic apparatus according to a modified example of the second embodiment.

FIG. 9 is an explanatory diagram of a target range of sensitivity correction according to the third embodiment.

FIG. 10 is a block diagram of a sensitivity corrector and a correction signal generator according to a fourth embodiment.

FIG. 11 is an explanatory diagram of a vector angle calculation method according to the fourth embodiment.

FIG. 12 is an explanatory diagram of a modified example of a vector angle calculation method.

FIG. 13 is a block diagram of an ultrasonic diagnostic apparatus according to a modification.

FIG. 14 is an explanatory diagram of a problem caused by a decrease in sensitivity in the direction perpendicular to the conventional ultrasonic beam.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ultrasonic probe, 2 ... Oscillator, 3 ... Reception delay circuit, 4 ... Adder, 5 ... High frequency amplifier, 6 ... Logarithmic amplifier, 7 ... Detector, 8 ... Receiver, 9 ... A / D conversion Reference numeral 10 ... Digital scan converter, 11 ... Sensitivity corrector, 11-1 ... Reference point setting unit, 11-2 ... Vector angle calculation unit, 11-3 ... Sensitivity correction unit, 11-4 ... Normal vector calculation unit, 12 ... D / A converter, 13 ... Display, 14 ... Gain controller, 15 ... Correction signal generator, 15-1 ... Reference point setting unit, 15-2 ... Vector angle calculation unit, 15-3 ... Correction amount calculation Section, 15-4 ... Coordinate conversion section, 15-5 ... Perpendicular vector calculation section, 16 ... Amplitude controller, 17 ... Sensitivity correction device, 17-1 ... Sensitivity corrector, 17-2 ... D / A converter, 17 -3 ... Display.

Claims (7)

[Claims] 1. An ultrasonic diagnostic apparatus for obtaining internal information of an object by transmitting and receiving ultrasonic waves to and from the object, comprising: a reception gain at a specific position in a scanning space for scanning the beam of the ultrasonic wave. Is adjusted according to an angle formed by a predetermined vector direction set at the specific position and a vector direction of the ultrasonic beam passing through the specific position. 2. An ultrasonic diagnostic apparatus for obtaining internal information of a subject by transmitting and receiving ultrasonic waves to and from the subject, the brightness of an image at a specific position in a scanning space for scanning the beam of the ultrasonic wave. Is corrected according to an angle formed by a predetermined vector direction set at the specific position and a vector direction of the ultrasonic beam passing through the specific position. 3. The predetermined vector set at the specific position is a vector from a point on the beam of the ultrasonic wave toward a reference point set in the scanning space. The ultrasonic diagnostic apparatus according to claim 2. 4. The predetermined vector set at the specific position is a vector from a point on a predetermined shape set in the scanning space to a reference point set in the scanning space. The ultrasonic diagnostic apparatus according to claim 1 or 2. 5. The super vector according to claim 1, wherein the predetermined vector set at the specific position is a perpendicular line at a point on the predetermined shape set in the scanning space. Sound wave diagnostic equipment. 6. The reception gain increases as an angle formed by a predetermined vector direction set at the specific position and a vector direction of a beam of the ultrasonic wave passing through the specific position approaches from parallel to vertical. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is adjusted to. 7. The brightness of the image increases as the angle formed by the predetermined vector direction set at the specific position and the vector direction of the ultrasonic beam passing through the specific position approaches from parallel to vertical. The ultrasonic diagnostic apparatus according to claim 2, wherein the ultrasonic diagnostic apparatus is corrected as follows.