DE2628708A1 - ULTRASONIC IMAGE DEVICE WORKING IN ACCORDANCE WITH THE PULSE ECHO PROCESS - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT 'Our sign Berlin and Munich VPA 76 P 5070 BRD

Ultrasound operating according to the pulse-echo method ^ Imaging device

The invention relates to an ultrasound imaging device operating according to the pulse-echo method, in particular for medical applications Diagnostics, with an ultrasonic applicator for line-by-line ultrasound scanning of an examination object and Image display device with line generator for mapping the echo pulses as a line and image generator for the shift of the line as a function of the displacement of the ultrasound beam in the object, with ultrasound scanning and echo line display take place in the manner of an interlace procedure.

In the German patent application P 25 57 529.5 an ultrasonic imaging device of this type has already been proposed, where means three ultrasonic transducers rotating around the focal line of a paraboloid reflector, three partial images in chronological order generated by the ultrasonic scanning and then these partial images by the image display device in the manner of an interlaced process nested together to form the full screen. With the proposed ultrasound imaging device Ultrasonic sectional images of the examination subject on the image display device with a high number of lines in the full image and a relatively high frame rate of the partial images (50 Hz). Since with this proposed ultrasound imaging device, however, the locations consecutively line-by-line scanning in the examination subject

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are relatively close to each other - the distance between two places one after the other Scanning within the fields is never greater than three times the line spacing of the lines in the frame Danger of stray multiple echoes from a previous scan line in the reception area of the subsequent scanning lines and are thus faded in as false echoes in the cross-sectional image recording.

The object of the present invention is to provide an ultrasound imaging device of the type mentioned at the beginning, which also works in the interlaced process, but in which there is a risk of fade-in of multiple echoes in the sectional image recording is largely banned.

The object is achieved according to the invention in that the ultrasonic scanning area of the ultrasonic applicator into a small number, preferably three, of adjacent scanning segments is divided according to a high number of scanning lines per scanning segment and that ultrasonic scanning in the individual scanning segments by the ultrasound applicator and recording of the respective echo pulse lines on the image display device in the Meaning that for each image run in chronological order in each scanning segment, the first, then the second, then the third, etc. up to the η-th segment lines are scanned one after the other and in a corresponding manner can be displayed as echo lines by the image display device.

With the invention, distances between the locations result in successive ones Ultrasonic scanning, which is no longer just three times the line spacing of the lines in the full image, but a multiple of this, namely the total raster width of the line field of a scanning segment (in the case of a full-screen raster with e.g. 120 lines and subdivision into a total of three segments, for example, the total jump of each scan is approx. 40 lines,

thus about thirteen times the scanning jump of the device according to the German patent application P 25 57 529.5). However, because of these locations of successive ultrasound scanning, which are relatively far apart, it is practically impossible

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sen that multiple echoes of a scan line can get into the reception area of a subsequent scan line, and the danger image falsification due to unwanted insertion of multiple echoes is thus largely eliminated.

Further advantages and details of the invention emerge from the following description of exemplary embodiments the drawing in conjunction with the subclaims.

Show it

Fig. 1 is a diagram of the deflection voltages for generating a Interlace method according to the invention,

2 shows a first exemplary embodiment for an ultrasound sectional imaging device for carrying out the interlace method according to FIG. 1,

3 shows a second exemplary embodiment for an ultrasound sectional imaging device for performing the interlace method according to FIG. 1.

^ ^N of FIG. 1 interlaced scanning of simplicity sake to the invention will be explained with reference to an ultrasonic image with a total of fifteen lines. Yixe already indicated, in a practical embodiment the ultrasound image naturally consists of a significantly higher number of image lines, for example 120 lines per full image. In the diagram according to FIG. 1, the total of fifteen lines Z ₁ to Z ₁ are shown in the picture above. "The order of the line numbers indicates the timing of the line structure on the screen of an oscilloscope tube. The respective position of a line Z ₁ to Z. c on the oscilloscope screen corresponds exactly to the respectively assigned ultrasound scan line in the examination object The sequence of the lines is chosen so that, for example, after the first line Z _1, the second line Z _{2 is written} in position six and, accordingly, the next line Z- is written in position 11. The line Z ^ then follows the line Z in position two ₂ , the line Z, - in position seven on the line Z ₂ and the line Zg correspondingly in position twelve

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on line Z, etc. Since the actual ultrasound scanning in lines after the same jump travels within a total of three Scan segments with the respectively assigned lines Z> ,,

^ 4 »^ 7» ^ 10 * ^ 13 ^ ^zw ^ 2 * ^ 5 * ^ 8 '^ 11' ^ 14 ^w * 3 »6 * 9 '12' Z ^ c takes place, ie the ultrasonic beam always ends the scanning of a line in one of the scanning segments to scanning in a subsequent line in the adjacent scanning segment, which is shifted from the first line positions as shown in FIG. 1 by only five, but in reality by a multiple thereof, e.g. forty , there is sufficient space and time to suppress multiple echoes of a line. To implement a line raster according to the upper part of FIG. 1 on the screen of an oscilloscope tube, the superimposition of a sawtooth-shaped breakover voltage Ug ^ with a stepped voltage Ump shown in dashed lines is used according to the voltage diagram in FIG. The staircase voltage is built up as a function of clock pulses T from a clock generator. In the exemplary embodiment according to FIG. 1, each stair pulse comprises a total of three stair levels.

The first stair level corresponds to the voltage level zero, while the next two stair levels are raised from zero level by such amounts that there are line jumps on the screen over five (in reality approx. Forty) lines per level. As a superposition product of Sägezahnkippspannung U _gK with the described steps voltage U _TR results in a Bildkippspannung with the solid line shown staircase waveform U _BK · One sees immediately that sequentially in time during a single image passage through this voltage U ^ all line positions Z ^ to Z ^ timed correctly and are displayed in the correct place on the screen. The line tilt for each line Z * to Z ^, - is also triggered at the correct time in the cycle of the individual clock pulses T ^ to T ^ j-. Each line tilt lasts no longer than the dwell time of the electron beam of the picture tube in the respective line step level of the picture tilt voltage UW.

Two exemplary embodiments for ultrasound cross-sectional imaging devices that use ultrasound scanning with a line image structure in the jump method

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allow according to Fig.1, are shown in Figs. 2 and 3 in the basic circuit diagram. Fig. 2 relates to an ultra

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Sound sectional image device that works with a total of six Tfe ^ earschallwandlerelemente W ₁ to Wg, which are rotatably arranged on a rotation carrier 1 in the focal axis 2 of a cylindrical parabolic reflector 3 about the focal axis. When the carrier 1 is rotating, the converter W ^ to Wg which is switched on sends an ultrasonic pulse in the direction of the inner surface of the reflector 3, from where it is reflected and emitted into an examination object. In FIG. 2, the path of such a pulse is indicated by dashed lines in the form of an arrow. With a rotating carrier 1 and alternating control of the individual transducer elements, there is thus a large number of successive ultrasonic scanning lines which are each parallel to the line US shown in dashed lines. In the exemplary embodiment according to FIG. 2, the individual transducer elements W ^ to Wg are in conductive connection with associated sliding elements 4 to 9, which are arranged on the carrier part 1, for example, in the manner of a commutator. However, only three sliding contacts 10, 11 and 12 are assigned to this total of six sliding elements 4 to 9. These sliding contacts 10 to 12 are connected to a switching part 13 which, depending on output pulses from a ring counter 14, which can be fed to the switching part via three pulse lines 15, 16 or 17, always has one of the sliding elements in chronological succession and thus also the associated transducer element W ^ to Wg connects with the transmission energy of a high-frequency pulse transmitter 18 in the transmission mode or with a receiving device 19 for receiving the echo pulses in the reception mode. The echo pulses received by the receiving device 19 (Earpfangsver stronger) are then fed to the light probe 20 of the cathode ray tube. An image tilt generator 21 with an associated line tilt generator 22 of the cathode ray tube (not shown in any further detail) is used in the usual way for image construction. To generate an image tilt voltage U ™, for the image tilt generator 21 in the sense of FIG. 1, however, a sawtooth generator 23 in conjunction with a staircase generator 24 and a voltage adder 25 are used. The sawtooth generator 23 supplies the sawtooth voltage Ugjj. and the staircase generator 24 the staircase voltage U _TO in the

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1. Through additive superimposition in the voltage adder 25, the image tilt voltage Ug _K = Ug _K + U _TR results from these two voltages according to the curve according to FIG , which generates clock pulses according to the clock pulse sequence T of FIG. The clock pulse generator 26 triggers the staircase generator with each clock pulse T., T ₂ , T, ff., While it controls the ripple generator 23, however, only with each first of a total of fifteen pulses comprising clock pulse sequence. In order to detect the first pulse of a new pulse sequence to trigger a sawtooth tilt at the sawtooth generator 23, a pulse counter 27 is provided which counts up to fifteen and is then reset to zero. Only the following next pulse, that is to say the respectively newly counted first pulse in the counter 27, then sets the tilt generator 23 in the sense of emitting a further tilt pulse Ug _K. A line toggle voltage generator 28, which also triggers a line toggle U ™ - in time with the clock pulses of the clock generator 26, is used to trigger the respective line tilt on the line tilt generator 22. In addition, the clock pulses of the clock generator 26 also serve to control the ring counter 14 or the frequency transmitter 18 to activate the individual transducer elements W ^ to Wg at the correct time and place in the sense of generating line jumps during the ultrasound scanning. In the exemplary embodiment according to FIG. 2, the ultrasound scanning and image display using the interlaced method according to the invention result as follows:

The clock generator 26 generates clock pulses T in pulse sequences of fifteen (actually about forty) individual clock pulses. Each of these pulse trains provides an image tilting voltage curve U _ßK according to FIG. 1. Each time the individual stairway levels are passed through, a row tilting generator 22 assigned to the level is triggered. On the screen of the oscilloscope tube there is thus a line raster of the electron beam with the line mapping course according to FIG. 1 above. The ultrasound scanning of the examination subject takes place at the rate of the clock pulses T of the clock generator 26 in leaps and bounds corresponding to the line leaps in the line raster on the screen 709852/0523

the oscillograph tube. The time and place correct activation of individual transducer elements W ₁ to Wg in the sense of the transmission and reception of ultrasound takes place by means of the ring counter 14 in connection with the switching part 13. The ring counter 14 generates output pulses rhythmically in time with the supplied clock pulses of the clock generator 26 at its Switching pulse outputs 15 to 17- The ring counter 14 is incremented by the pulses from the pulse counter 26 in packets of three pulses each. Each first pulse of such a package is thereby the output 15 of the ring counter 14, the respective second always the output 16 and the always third each pulse the ^O utput of the ring counter 14. This means therefore based on the instantaneous representation according to Fig. 2, that In connection with the deflection diagram according to FIG. 1, _{the output 15 of the ring counter 14 is set by the respective first switching pulse T 1 of} the clock pulse train T of the clock generator 26 and thus the converter W ₁ via the grinding element 4 through the switching part 13 with the high frequency ' ender 18 is connected. The transducer W ₁ thus sends an ultrasonic pulse in the direction of the reflector 3, which is reflected by the latter and radiated into the examination object. The echo signals occurring along this Einstrahlweges are in turn received by the converter W ₁ and now the echo signal receiver 19 and from this the light probe 20 of the electron beam to light scanning of the electron beam in the rhythm of the attack of the echo pulses fed. Since, however, at the same time as the clock pulse T _{1 of} the clock generator 26 occurs, the image tilting voltage U _{BK is} also located in the staircase level Z ₁ , these echo pulses are displayed in the form of line Z ₁ on the oscilloscope screen due to the line tilting triggered in this position. _{If a second clock pulse T 2} now occurs at the output of the clock generator 26, the output at the ring counter 14 is set. Thus, the converter is now W ₁ W ₂ activates the converter for the purposes of transmission and reception of ultrasonic under shutdown. Due to the spatial distance between the two transducer elements W ₁ and W ₂ , there is also a correspondingly large distance between the ultrasonic line generated _{by transducer W 2 and} that previously generated _{by transducer W 1.}

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- yj / l 76 P 5070 BRD With the selected total number of a total of fifteen ultrasonic scanning lines per image, the result is a spatial jump of the ultrasonic scanning line over a third of the total number of scanning lines, ie over a total of five ultrasonic scanning lines. The ultrasonic echo impulses obtained from this second line are in turn shown as a corresponding: image line on the screen of the oscilloscope. However, according to FIG. 1, this image line is line Z, since the image breakover voltage Ug _{K has} jumped to level Z _{2 when the second clock pulse T 2 of the clock generator 26 occurs.} On the screen of the oscilloscope tube there is accordingly an image line jump from Z ₁ to Z ₂ by five line positions in each case, corresponding to the line jump of the ultrasound scan. Corresponding line jumps by the same number of lines in each case then also result in the subsequent further ultrasound scanning. In the following, for example, with the third clock pulse T ^ of the clock pulse generator 26, the output 17 of the ring counter 14 is set and thus the converter W- is activated in the sense of sending or receiving ultrasound _{with the converter W 2 switched off.} The associated spatial jump of the ultrasonic scanning line corresponds to that of the scanning line of the transducer W ₂ with respect to the scanning line of the transducer W ₁ . On the screen of the oscilloscope, the echo pulse image line Z, is accordingly obtained with the present stair level Z, the image breakover voltage Ug _{K. The converter W 1 is} then again activated with the fourth clock pulse Tr of the clock generator 26. Due to the clockwise rotation of the transducer carrier 1, however, the transducer element 1 is shifted clockwise by the grid spacing of two lines. The fourth ultrasonic scanning line now results close to the first ultrasonic scanning line Z ₁ . _{Since the image breakover voltage U BR is} at the level Z ^ with the fourth clock pulse T ^, line displays in position Z ^ appear on the screen of the oscilloscope tube. Correspondingly, with subsequent switching to the transducer elements W ₂ and W-, shifted ultrasound scanning and corresponding line display on the screen of the oscilloscope tube in lines Zc and Zg Clock frequency of the clock

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pulses of the clock generator 26 reduced by a factor of three. This means that, for example, in the representation according to FIG. Each of the transducers W ₁ to W ^ scanned and scanned the examination object in three adjacent scanning segments each with five associated ultrasonic lines during an image period (fifteen lines, ie a total of fifteen clock pulses of the clock generator 26) has rotated a total of five line steps, corresponding to about a third of the reflector arc length, in a clockwise direction. At the end of the first image period described, the converter W ₁ is thus in the position of the converter Wp shown and the converter Wp is in the position of the converter W ^ shown. The transducer W ^, however, has moved out of the area of the reflector inner surface of the reflector 3 in a clockwise direction. His sliding contact element 6 is therefore no longer in contact with the sliding contact 12 and the converter W ^ is thus initially completely switched off for the next following image recordings. In contrast, the converter Wg has entered the previous position of the converter W _{1 and} is now in contact with the sliding contact 10 with the sliding element 9 that is now specifically assigned to it. The image construction of the following second ultrasound image is now carried out with the transducer elements Wg, W ₁ , Wp in the same way as was described above for the transducers W ₁ , Wp and W. The same then also applies to the third ultrasound image when the transducer elements W ^, Wg and W ₁ etc. are put into operation, until the present transducer configuration with the transducers W ₁ , W ₂ and W as active elements is reached again at the beginning of the seventh image. In cyclical repetition, the seventh ultrasound image is again generated in accordance with ultrasound image one, the eighth in accordance with ultrasound image two, and so on.

In the case of the ultrasonic sectional image device in the embodiment according to FIG. 3, the line jumps of the ultrasonic beam occur at the scanning of the examination subject and the corresponding line jump of the image line in the same manner as in the exemplary embodiment according to FIG. 2. However, differences arise insofar as in the embodiment according to FIG. 3 as an ultrasonic applicator an ultrasound array is used that consists of a total of

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fifteen (in the actual embodiment, however, from approx. 120) individual transducer _{elements W 1} to W ₁₅ (piezoelectric crystal platelets), which are arranged in a row next to one another on a carrier part 29. Each of these transducer elements W ₁ to W ₁ , - a switch S ₁ to S _{15 is} assigned to a switch bank 30, each of which in the closed state has its assigned transducer element with a high-frequency transmitter 18 for transmission or with an echo pulse receiver 19 with downstream Light button device 20 connects the cathode ray tube during the receiving operation. The switching elements S ₁ to S *, - of the switch bank 30 are controlled as a function of control pulses from a shift register 31. The shift register 31 has a total of fifteen outputs A. to A ₁ 1- via a wiring bank 32 with the control inputs B ₁ to Bj- the switch S ₁ to S ^ wired in such a way that the output A ₁ with the control input B _{1 of} the switch S ₁ , A _2, however, with the control input Bg of the switch Sg, the output A ₇ , however, with the control input B. _{11 of} the switch S ₁₁ etc. is firmly linked in the form shown. If the structure is chosen in this way, then, when a single pulse is passed through the shift register 31, which is fed into the shift register via the signal input 33 from the pulse counter 27 at the beginning of each ultrasound scan, the clock pulses T of the clock generator 26 fed to the register shift input 34 are synchronized above

25 the progressively set outputs A ₁ to A ₁ p- control of the switches S ₁ to S ₁₅ in the order S ₁ , Sg, S ₁₂ , S ₂ , S ₇ etc. However, when these switches are switched through in the order described, this results Transducer excitation in the order W ₁ , Wg, Vr ₁₂ , W ₂ , Wy etc. and thus ultrasound scanning in line jumps corresponding to those of the exemplary embodiment according to FIG. 2

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Claims (7)

76 P 5070 FRG claims 1. Ultrasonic imaging device working according to the pulse-echo method, especially for medical diagnostics, with an ultrasonic applicator for line-by-line ultrasound scanning an object to be examined and an image display device with a line generator for mapping the echo pulses as a line and Image generator for shifting the line as a function of the shift of the ultrasonic beam in the object, with ultrasonic scanning and echo line display are carried out in the manner of an interlace procedure, thereby identifying TO records that the ultrasonic scanning area of the ultrasonic applicator (1 to 6, W .. to Wg or 29, w ^ to w ,,, -) in a small number, preferably three, adjacent scanning segments with a correspondingly high number of scanning lines per scanning segment is divided and that ultrasound scanning is divided into -j 5 individual scanning segments by the ultrasound applicator as well as recording of the respective echo pulse lines (Z ^ to Z-jc) ^on the image display device in the sense that for each image run in chronological order in each scanning segment first the respective first, then the second, then the third "etc. up to the η-th segment lines are scanned one after the other and displayed in a corresponding manner by the image display device as echo lines. 2. Ultrasonic imaging device according to claim 1, characterized in that each scanning segment is optional for segment scanning either just a single ultrasonic transducer (W,. to Wg) that can be moved line by line in the segment or a whole group associated with a plurality of immovably juxtaposed ultrasonic transducers (w ^ to w ^ c) of the ultrasonic applicator is. 3. Ultrasound imaging device according to claim 2, characterized in that when only a single movable transducer is assigned for each scanning segment, the individual transducers currently in the scanning segments (eg W ^, W ₂ , W ^,) are excited cyclically one after the other and after corresponding to each excitation cyclically by one scanning line 709852/0523 - ^ 2 - J / 76 P 5070 FRG touch segment can be moved further and then cyclically excited again. 4. Ultrasonic imaging device according to claim 3, characterized gekeniizeichnet, that each of the individual transducers (W .. to Wg) each of the scanning segments is spatially and temporally assigned in the sense that, once the segments have been scanned, those associated with this scanning previously used transducer is moved further into the respective adjacent segments and there in a further scanning pass be activated again to scan these scanning segments. 5. Ultrasonic imaging device according to claim 3 or 4, characterized in that in the design of the ultrasonic applicator as a paraboloid reflector (3) with individual transducers rotating around the reflector focal line, a total of preferably six individual _{transducers (W 1} to Wg) each with three active transducers (e.g. W- to W ^) are present in the catchment area of the reflective surface of the reflector (3), each of the six individual transducers scanning the reflective surface of the reflector in three consecutive thirds of the segments in cyclical exchange within six successive passes of the ultrasonic scanning. 6. Ultrasonic imaging device according to claim 2, characterized in that that in the formation of the ultrasonic applicator s as an ultrasonic array with a large number of juxtaposed Transducer elements (w ^ to w>, r) in the scanning segments . Each associated adjacent transducer element groups ultrasonic excitation and further clocking of transducer elements takes place individually or in subgroups, in the sense that for each Image scrolling in chronological order in each transducer element group first the first in each case, then the second, then the third, etc. up to the η-th individual elements or subgroups are excited one after the other. 7. Ultrasonic imaging device according to one of claims 1 to 6, characterized in that for generating a line grid 709852/0523 - yf- 76 P 5070 FRG _{the superimposition of a sawtooth-shaped breakover voltage (Ug K} ) with a staircase-shaped voltage (Umtj) is used on the image display device in accordance with the ultrasound scanning in the examination area, whereby the staircase voltage is built up as a function of clock pulses (T) from a clock generator (26) and the staircase levels correspond to the distances desired line jumps within the scanning segments are selected accordingly. 709852/0523 40