Display and recording system for ultrasonic diagnosis

(54) Title: Device for medical diagnostics with ultrasound (56) Published publications: --7700657-5

The present invention relates to an improved device for medical diagnostics with ultrasound. The device includes a multi-element signal converter for generating and receiving ultrasonic energy which is propagated to and reflected back from the cardiovascular region of the patient under examination and which also includes means for generating a two-dimensional real-time recording and / or image of the area under examination. TM recording means belongs to the device and can be switched on to perform a TM recording corresponding to a pre-selected portion of the real-time image observed. An ECG output signal is also recorded in real-time with the two-dimensional image and photographs of the registrations can be obtained at specific points in the ECG cycle according to a setting made by the system operator. The device includes a device for generating video recordings, as well as means for adding various identification and time data to the recordings.

The present invention relates generally to apparatus and methodology for performing medical diagnosis, and more particularly to systems and methodologies that use ultrasound technology for such purposes.

Over the past 20-30 years, ultrasound technology has played one

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- 2 ever-increasing role in medical diagnostics. One area of ​​particular interest for the present purposes is the use of such techniques for identifying and examining heart structures. At least as far back as 1953, Edler and Hertz described techniques in which echoes generated by heart structures could be transformed into curves that indicated movements in parts of these structures.

Techniques of this type have been widely identified by the term echocardiography or by the term TM scan (Time-Motion). According to these techniques, a narrow ultrasound beam is thrown into the heart region from one superficial transducer, which is placed, for example, so that the beam spreads between the ribs. As a pulse of ultrasonic energy is propagated inwardly through the various structures including heart wall, flaps and the like, some of the energy is reflected back towards the transducer at the boundaries between the various structures. This reflected energy is then captured, amplified and recorded as desired on the oscilloscope or on the printer strip.

The kind of information collected by said techniques can be of great diagnostic value as the structures examined are changed in a characteristic manner in certain heart diseases and an experienced physician can easily detect such changes by examining properly obtained records of said type.

Regarding TM scanning, it can be found that until recently a major problem with the applicable apparatus was that the operator was essentially blind-flung. That is, the only information the operator had about whether the transducer was properly oriented for the structures he was trying to examine was obtained by studying the data recorded on the oscilloscope or on the printer strip. According to this method, the operator had to tilt or angle the transducer to cover and scan a series of structures from which he wishes to obtain registrations. The only feedback he received whether the registration made really included the structures that he wanted to study was thus obtained afterwards.

Recently, apparatus has been described in which a TM scan can be obtained from a B scan obtained with a near field system. The difficulty is that the TM scan images obtained with a near field system are not well known to diagnostics and for this reason are not easily correlated with the investigated structures.

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- 3 Next, it should be noted that a number of ultrasound imaging systems have recently been shown, and in some cases have become available for use by researchers, which allow a two-dimensional image, for example of a heart structure, to be generated and observed in real time. A system of this type that uses phased system principles to control and focus an ultrasound beam generated by a system of transducers, is described by Thurston and von Ramm in A New Ultrasound Technique Employing Two-Dimensional .Electronic Beam Steering, in Acoustical Holography, vol. . 5, Ed PS Green, Plenum press, 1974. Further aspects of systems based on such apparatus are set out in Vol. 6 of the Acoustical Holography, p. 91, in an article by von Ramm, Thurston and Kisslo entitled Cardiovascular Diagnoses With Real Time Ultrasound Imaging. Reference may also conveniently be made to JC Somer, Electronic Sector Scanning for Ultrasonic Diagnosis, on page 153 of Ultrasonics, July 1968.

The above-mentioned real-time imaging systems and other such systems recently described by other researchers have really provided useful new tools to the medical diagnostician in that, for the first time, it has become practically possible to directly observe an expanded portion of cardiac function in real time or essentially simultaneously with these features. At the same time, however, such systems have represented only a first approach to an extremely complex diagnostic environment. The systems described have noticeably lacked the finesse and flexibility required by the diagnostician. For example, many of these prior art systems have provided poor resolutions in the obtained images, and have not included opportunities to manipulate the image to concentrate on or investigate certain specified regions of the heart or nearby cardiovascular structures. Perhaps more important is the fact that these known devices have not been able to enable a diagnostic relationship between the B-type indication they provide and the various additional diagnostic evaluations commonly used by the cardiologist - for example, the well-known ECG, phonocardiogram and the aforementioned TM scans.

In accordance with what has been said so far, it can be considered an object of! The present invention provides a device for ultrasound diagnostic indication and recording, which device is particularly useful in cardiology, and which can show directly to the operator a real-time view of the high-resolution heart structure and with good manageability.

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It is a further object of the present invention to provide a device of the aforementioned type which includes means which enable simultaneous or independent indication of ECG slider phonocardiograms in a form which allows the system operator to readily observe this data.

In addition, it is a further object of the present invention to provide a diagnostic device in which ultrasonic methodology is used to illustrate, in a solar-powered indication, real-time heart structures or the like and thus enable a so-called B-type indication of such structures, the device further comprising means for to quickly and automatically scan or scan the TM type of the part of the heart structure indicated.

It is a further object of the present invention to provide an imaging ultrasound device which is particularly adapted to generate real-time B-type indications of cardiac structures, which device includes means for automatically taking photographs of said B-type indication, and in which the photography of said indication can be directly correlated to a time point referring to an ECG which is generated by the cardiac structure observed; and thereby enabling this cardiac structure to be photographically documented at exactly the point in the cardiac cycle that is considered to be of diagnostic interest.

Yet another object of the present invention is to provide a diagnostic ultrasonic device of the above type which, in addition to containing means for obtaining photographs of the B type indication in real time, also includes means operated by the operator to superimpose alphanumeric information and time information on the indication. wherein the resulting photographs are directly provided with accurate data which is useful for joumal guidance or other purposes, for example, medical thyroid purposes or for designing prescriptions.

Yet another object of the present invention is to provide a diagnostic ultrasonic device of the above type which, in addition to containing means for providing a video recording of the B-type indication in real time, has means for superimposing exact time information on the indications recorded to thereby facilitate and ensure reliable analysis of registrations.

According to the present invention, the above objectives are met and

7700657-5 others which appear from the following description with a device having the features specified in claim 1. The invention thus relates to a device for indicating and recording ultrasound which, in addition to providing a real-time image of heart structures or the like, which has good resolution and is easily manageable, contains a wide register of additional characteristics which cooperate with the aforementioned real-time imaging means on such a device. means that a far-reaching improvement in the diagnostic possibilities of the system is possible.

The signal converter soti used in the device of the present invention conveniently comprises a phased system consisting of a plurality of elements arranged in a compact linear system. The signal converter is coupled to a suitable transmitter and receiver, and the transmitted pulses have such a phase that the transmitted sound beam is controlled in the desired direction. Adjustable delays in each receiver channel increase reception from the direction of the transmitted sound beam. By appropriately controlling the time course of the voltages applied to the signal converter elements and it. adjustable delays in the individual receiver channels, the beam can be controlled to any desired angle by the solar spring-shaped sector. The controlled system may operate in such a way that a plurality of radial lines defining the spring-shaped sector are generated in turn in relatively high numbers, typically in the order of 64 such lines used to generate the entire sector. The set of these lines is generated for a short period of time, typically of the order of 1/30 second, with the corresponding indication on the system's cathode ray tube (CRT) being a good resolution image, essentially in real-time (or at high speed) of the heart and adjacent cardiovascular structures. , said image being of the so-called B type, that is, an image in which variations in the acoustic impedance of the tissue are transformed into variations in illumination intensity on the cathode ray tube screen.

Use of the phased sector scanner provides significant benefits when cardiovascular structures are to be visualized and measured. It allows the heart area to be illustrated by the relatively limited opening between the ribs. It also offers the cardiologist a small lightweight transducer similar to those used in previous TM type instruments. In previous TM-type instruments, the cardiologist would examine the various cardiac structures by angling the transducer so that it would transmit the beam in turn through the interesting structures, after which they were recorded on a TM-type printer strip. According to the present invention, the same type of indication is obtained automatically by allowing the cardiologist

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- 6 obtain a TM type scan of the two-dimensional image observed on the cathode ray tube screen.

Hitherto known near-field ultrasonic scanners with linear systems do not allow the same indication to be translated into a TM scan as they indicate the B scan image in rectangular form instead of the angular shape obtained in the sector scanner. Thus, one of the advantages of the present invention is that it allows a TM indication to be recorded in the form common to hitherto known TM registrations with the advantage that the structures can be illustrated in their actual configurations before and indeed at the same time as the TM registration is made .

The device contains means for varying the sector size of the solar spring-shaped surface which the signal converter examines to obtain a desired angular shape varying, for example, between 20 and 80 degrees. Since the same number of scan lines is used at each time, increased resolution permits when a particular section of the image is judged to be of particular interest.

According to one embodiment of the present invention, there are means for varying the repetition rate theory of the scan lines to enable control of the depth of the indicated scanned sector. With this technique, examination of less deep portions of the cardiac structure can be performed with a corresponding increase in line density. For example, when structures close to the maximum width of 21 cm are examined, a total of 64 lines are used. By limiting the maximum depth to 7 cm, a total of 192 lines can be used, which gives higher sensitivity, for example when examining children.

According to another embodiment of the present invention, the data processed by the receiver connected to the transducer can be varied so that parts of this data can be compressed, i.e. so that non-linear treatment is possible. The device may contain means for rejecting signals below a certain amplitude ie. to allow noise display.

According to another embodiment of the present invention there is for the control made possible by the device line at^! sector-shaped indication means for varying the gain of the receiver in different sectors of the investigation zone. In this way, it is possible to compensate for areas with greater damping that may occur in certain parts of the body.

As already mentioned, the grinding according to the present invention permits direct

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- 1 visible indication of a cathode ray tube available to the operator. A slave oscilloscope is operated synchronously with the intended indication and a photographic camera equipment is located so that photographs can be obtained directly from the slave oscilloscope. The slave oscilloscope is also connected to a video icon whose outputs lead partly to a videotape recorder and partly to a video monitor as a backup option for viewing the indication or to enable the indication to be viewed from a distance.

The output of the signal converter receiver is also coupled to a TM printer which enables the recording of TM strips directly from the device of the present invention. A particularly important consequence of this arrangement is that the system operator can start a TM registration while studying the indication that is essentially in real time. In this way, the disadvantage associated with the prior art is completely eliminated by the fact that the diagnostician is forced to work in partial or total awareness of the particular area of ​​the patient for which he prepared the said TM registration.

In addition, the TM application contains certain possibilities that have not hitherto been available in such instruments and, of course, in the presence of a notably improved possibilities presented by the present system. Thus, in addition to the ability to perform a TM record for time movement characteristics along one or more selected radial lines of the sector scanner, the present system can operate automatically, successive TM scans being performed on each adjacent radial line to thereby obtain a TM record of the entire sector. which is observed by the operator on the system indicator screen.

The device of the present invention further comprises ECG inputs through which ECG data from the patient can be directly inserted into the device. · Appropriate ECG is indicated in real time on the system indicator screen, and means are also provided which ensure that the generated ECG pattern remains sufficiently long. to enable the operator to identify significant characteristics therein.

According to another embodiment of the present invention, a runner (e.g., an index mark) is generated on the cathode ray tube screen, which can be moved by the operator and which can be placed at a desired point on the ECG strip. This action has a very significant impact on the production of photographs. Means are specially arranged in the device to make it possible

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- 8 make photographs corresponding to the real-time image at the point in the heart cycle identified by the runner. This allows the operator to obtain a photographic reading at exactly the point in the cardiac cycle that he considers to be of significance for the examination.

According to yet another embodiment of the present invention, means are controlled from the control panel to generate alphanumeric characters to enable alphanumeric and other information to be entered on the visible indication. In this way, the operator can enter information regarding, for example, the patient's identity, examination date, and other data that is of interest to the diagnostician or the institution performing the examination of the patient. In addition, instrument parameters and associated data are automatically indicated such as at which point of the heart cycle the photograph was taken. Information of the latter type can be correlated with the position of the aforementioned runners, and can also be added to the indication in the form of time data indicating the time offset from Rvagen or from any other significant time point in the ECG cycle.

A clock display can likewise be inserted on the display screen to provide continuous recording which can extend down to 1/100 second, with each complete exposure (1/30 second) bearing a distinct time identification. This type of information is important for the aforementioned photographs and is of particular value in interpreting the video recordings that can be recorded using the system of the present invention.

The collection of the aforementioned categories of data for identification and the like has been judged not only to be of importance for the purposes of normal registration, that is to facilitate the correlation of photographs and video recordings with patient records or the like, but in addition, the said information is considered to be essential in connection with with medical-legal problems and / or when drafting regulations, that is, to comply with requirements that may be issued by the hospital or institution using the equipment or by public authorities.

The invention will now be described schematically with the aid of the following drawings.

Fig. 1 is an electrical block diagram showing the main elements of a device according to the present invention.

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Fig. 2 is a schematic plan view of the indicator screen portion of the device of the present invention.

Fig. 3 is an electrical block diagram showing the TM type operation of the device and also indicating certain details of the sector generation technique.

Figures 4A, 4B and 4C show curves showing certain aspects of the process taking place in the production of photographs by the apparatus of the present invention, and

Fig. 5 is an electrical block diagram showing the electronic retention circuits and exposure sequence shown as block 56 in Fig. 1.

Fig. 1 shows an indicating and recording device 10 according to the present invention. The device or system 10 operates according to ultrasound principles and is primarily intended to carry out the diagnosis of cardiovascular and cardiovascular conditions, although it is obvious to one skilled in the art that this system is useful in other diagnostic applications in such a way that the system provides useful information in other parts as well. of the body. However, because of its primary application of cardiovascular and cardiovascular diagnostics, this application of the system will be emphasized in this specification.

The audio signal transducer 12, used in the system 10, is operatively connected to a patient 14 to allow the ultrasound beam generated therefrom to be transmitted into the cardiac region and surrounding structures. The signal transducer 12 may, as in the prior art, be positioned to emit its sound beam between the patient's ribs.

Although various such signal converter devices which are known to be useful in the production of two-dimensional images can be used in conjunction with the present invention, for example, those based on so-called near-field "linear systems, the signal transducer 12 preferably comprises a phased system which, for example, consists of a plurality of elements such as, for example, 32 piezoelectric elements arranged in a compact. linear sequence. In a typical case, each such element may have a length of 12mm, a width of 0.3mm and a distance between the midpoints of adjacent elements of 0.4mm. In general, the signal transducer should be of a physical size that allows efficient use in conjunction with one

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- patient, such as, for example, sending ultrasound between the ribs to perform an indication of the heart area. The thickness of the specific signal converter element used is determined by the operating frequencies and can typically be of the order of 0.7 mm when a frequency of 2.5 MHz is used.

The signal transducer 12 is connected via a switch and logic circuit to a transmitter 16 and a receiver 18 and transmitted pulses of the desired ultrasonic frequency are phased by the time sequence of the voltages applied to the individual signal transducer elements to control the transmitted sound beam in the desired direction. Adjustable delays exist in each receiver channel which increases reception from the same direction as the transmitted sound beam. By timing the voltages across the signal converter elements and controlling the adjustable delays of the separate receiver channels, the sound beam is controlled to the desired angles in a spring-shaped sector. The operation of the controlled system, of the phasing and of the delay frequencies is carried out so that a plurality of radial lines defining said solar spring-shaped sector are generated successively, with a relatively high number, typically of the order of 64-256, being used to generate the entire sector. A set of such lines is generated for a short period of time, typically in the order of 1/30 second, with the corresponding indication (FIG. 2) on the display screen 24 of the system is a high-resolution and substantially real-time image of the heart and associated cardiovascular structures, said image being of the so-called B type, that is, where variations in tissue impedance are translated into light variations on the cathode ray tube screen.

The output of receiver 18 is routed via line 20 in parallel to three instruments. First, the output is coupled via line 22 to a visual display screen 24, which, as mentioned in the typical case, is in the form of a conventional cathode ray tube display which can be directly observed by the system operator. However, it may include other display devices such as, for example, a plasma display panel. Via line 26, said output is also connected to a slave oscilloscope 28. The slave oscilloscope 28 and the display screen 24 operate synchronously with the aid of the operating circuit 30, which, if using cathode ray tubes, provides the required deflection voltages for each cathode ray tube. In conse7700657-5 sequence herewith is precisely the indication which is visible at any moment to the operator on the screen 24 also present at the same time on the slave oscilloscope 28.

With the slave oscilloscope 28, reproducing devices are operatively associated, including, for example, a photographic camera 32 which is set at a certain distance from the cathode ray tube screen of the slave oscilloscope to enable direct photography of this screen at selected times. An output image is also taken at 34 from the slave oscilloscope 28 and is led to a conventional video icon 36. This video icon 36 is in turn coupled to a VCR 40 from an output 38. A video monitor 42 may also be provided to display the information thus recorded. The various latter elements and their working methods are well known to those skilled in the art and therefore no further details are given regarding their functions and how they are linked to each other.

According to a preferred embodiment of the present invention, a third parallel socket from receiver 18 is connected via line 42 to a TM printer 44. TM printers are known per se to those skilled in cardiac diagnostics. In the usual application of this apparatus in echocardiography, sound-changing characteristics are recorded along a linear direction in the structural examination on a strip 46 as it moves with time. Thus, in this kind of device, the resulting pattern indicates the movement in time of the structural detail observed by eco-technique. The TM printer 44 used in the system of the present invention is of the same type. While the manner in which the printer interacts with the other elements of the system 10 produces new and highly unexpected results (which will be discussed below), the printer as such may have a conventional design. Thus, a Honeywell model 1856 printer can be used in the system as well as several other devices of this type which are known.

Thereafter, means for sensing and recording ECG are shown in association with system 10. In particular, an ECG sensor 50 is provided which may constitute the usual electrodes and associated equipment which can be operatively associated with the patient under examination. The output of sensor 50 is coupled to an ECG amplifier 52. According to this embodiment of the present invention, the output 54 of the ECG amplifier 52 is coupled, after being processed by electronic retention circuits in block 5 (via line 58 to the visual display screen 24 as well as to the slave oscilloscope 28. It will be appreciated that the ECG signal reproduced on the cathode

The beam tube screen 24 is generated in real time and therefore would in principle only be visible as a bright spot moving across the screen. In order to make the signal useful for analysis by the operator, it is necessary to carry out the retention of the displayed signal during at least one part of the ECG cycle sufficient for the operator's analysis. The electronic retention circuits in block 56 are present to accomplish this. The apparatus for this purpose is shown in FIG. 5 and are described in more detail below. Essentially, retention acts to reproduce a portion of the ECG signal for the desired time. In a typical case, with reference to Fig. 2, the point 103 may be assumed to represent the rendered point of the signal, that is, the point generated in real time on the cathode ray tube screen 102. However, the portion of the signal denoted by 101 may be retained by the circuit of block 56 so that this portion of the displayed signal remains visible for examination by the operator.

According to a further embodiment of the present invention, it may also prove useful to provide phonocardiographic aids or other physiological indication and recording devices in addition to the ECG input. Thus, a microphone 60 is provided whose input is coupled to a phonocardiograph 61 and thence via auxiliary amplifier 62 to the same electronic retention circuit in block 56 used in the ECG system so that the phonocardiographic signal can be placed on the visual display screen 24 if desired. , is photographed or the like by the various registration elements in the system. Similarly, other physiological input signals indicated by the participating block 63 for a physiological input may be amplified by the amplifier 62 and fed to the circuits of block 56. The participating input 63 is a respiratory control means.

A control panel input 64 actuated by the operator is located in the system of the present invention which enables identification data and additional important information to be entered on the various indicators. In particular, the control panel controls an alphanumeric character generator 66 and / or a clock 68 which provides time data and various alphanumeric identification data via lines 70 and 20 to visual screen 24 and slave oscilloscope 28. Referring to FIG. 2 you can see that some information of this kind can be entered on the screen by the operator. For example, patient identification data with numbers, names and so on at 104 and operator identification at 105, examination data at 106, time information at 107, and camera7700657-5 sequence information at 109. Enter data at 111 including the time elapsed from the peak of the R-wave in the ECG until the time the camera takes a picture of the B scan date as explained in more detail below.

The kind of information that is indicated serves several important purposes. In the simplest case, identification data as they appear on photographs and videotapes obtained with the system of the present invention enables direct identification of the records to the patient, avoiding any possibility of error. The time information is indispensable in connection with the video recordings made with the video recorder 40. Since the time information is normally given in hundreds of seconds, it uniquely identifies each image on the cathode ray tube (that is, each image is retained 1/30 second). Thus, study of the video recording together with the time information can enable the precise determination of the movement characteristics of the depicted structures.

It should also be considered that the various data mentioned above is considered to be of increasing importance from the medical-legal point of view as well as by the controlling authorities. In many cases, hospitals and similar institutions thus require or at least wish to, because of their own internal regulations or requirements, set by insurance companies and so on, accurate data of the kind mentioned for use in any trials based on diagnosis, and similarly impose on public authorities. increasingly stringent claims on identification data associated with medical records.

The camera 32 associated with the device of the present invention may be of conventional construction. Various models of the well-known Polaroid cameras as well as display-type xerographic cameras, such as those commercially available from Varian Associates, are well suited for these purposes. According to the techniques used in the present device to enable photography of indications on the slave oscilloscope 28, a camera logic 80 is provided including appropriate logic circuits for activating the camera operating means 82 which, by means of electromechanical or similar devices, actuate the camera 32 to perform an exposure at the desired time. The operator selects the point in the ECG indication at which the photographic exposure is to be performed using the camera logic 80 and the circuits 56 for electronic retention and exposure sequence. Especially the latter which acts through the runner position switch 95 moves one

7700657-5 runner marking to a predetermined area of ​​the ECG indication 101, such runner indication being, for example, a stronger illumination of the ECG indication at the desired point. Such a point is indicated in Figure 2 or point 108.

The timing of the camera sequence is explained using Figures 4A-4C. When a photograph is desired, camera logic 80 is activated by the operator which initiates photo sequence means 85. After activation shown at time 83 on ECG 100 in Fig. 4A, camera logic 80 immediately disables the slave oscilloscope screen by receiving the operating signal on line 81 from the control control logic. 114 and prevent it from being directed to the slave oscilloscope 28 via lines 78 and 79. The inactive and operative conditions of the slave oscilloscope 28 are depicted in Fig. 4B. The camera logic 80 opens via the actuator 82 the shutter of the camera 32 as shown in Fig. 4C. The system then continues to operate with the slave oscilloscope screen inoperative until the next R-wave (Fig. 4A) is detected by the circuits 56 for electronic retention and exposure sequence. When the horizontal portion of the ECG reaches the runner marker 108 at time 89, a trigger signal is sent from the circuits 56 to the slave oscilloscope 28 so that the B scan is made to display an image of cardiological data on the slave oscilloscope 28. This operating period lasts approximately 20 milliseconds which is sufficient for to. indicate and register an image of B scan data.

The slave oscilloscope 28 is then rendered inoperative (at 93 in Fig. 4B) until approximately 1 second later (at 97) when another period of operation occurs. This time, however, only the ECG signal on the slave oscilloscope 28 is activated so that this information is displayed to the camera. The system is then rendered inactive again (at 99) and the camera shutter is closed, after which the indication is again activated and normal operation continues. The film in the camera is then forwarded and the system is ready for an image or for continued normal operation.

Further, it can be found that multiple exposure setting devices 98 are provided adjustable by the operator to allow repeated exposures to the same photographic plate of the selected portion of the cardiac cycle. This may be desirable in some cases to obtain sufficient exposure or contrast in the photographic film or plate.

Fig. 5 is a block diagram showing the circuits 56 of Fig. 1 for electronic retention and exposure sequence. These circuits make it possible

7700657-5 to indicate a retained ECG signal on the main screen and on the slave oscilloscope 28 and provides signals using camera logic 80 to enable photographs to be recorded at a predetermined point in the cardiac cycle.

ECG signals from the ECG amplifier 52 and phonocardiogram signals from the amplifier 62 are coupled via the wires 54 and 55, respectively, to the amplifier 552 for amplification to a level suitable for digitization, typically in the voltage range 100-1000 millivolts. These signals are then digitized by the analog-to-digital converter 554 and fed to the memory with constant access time 556. The address of the memory 556 is determined either by the display counter 558 or by the acquisition counter 560. The transmit-receive exchanger 562 determines which of the counters is coupled to the memory 556. During the acquisition phase of the ECG signal, the exchanger 562 provides coupling only from the acquisition counter 560 to control the address of the memory 556. The address of the counter 558 is derived directly from the clock 564 and the address of the counter 60 is derived by dividing the frequency of the clock 564 by the divider 566. In a typical example, the clock 564 can operate at a frequency of approximately 51 kHz and the divider 566 can typically divide this frequency by 256 leading to a frequency of approximately 200 Hz as the input frequency of the counter 560. The counter 560 will continue to increase when it receives pulses from the divider 566 until the counter is filled, that is, until a substantial binary output is obtained in line 568. An output in line 568 switches flip-flop 570 so that the signal in line 572 is reset to prevent further counting of counter 560. Counter 560 maintains this state until the next R-wave is detected by the peak detector 574. When an R-wave is present on the peak detector 572 a voltage on line 576 to ANDgrind 578. If the counter 560 is filled, a considerable binary signal in line 568 prevails and the flip-flop 570 maintains a positive signal at the Q output 580. The combination of this positive signal of 580 and the positive detector signal of the peak detector 574 activates the AND gate 578 so that it gives a positive signal of 582 applied to the reset inputs of the counter 560 and the reset input of the flip-flop 570. The acquisition counter 560 increases as it receives 56 pulses . By means of the devices described above, the address of the constant access time memory 556 is set to its lowest address at the peak of the R-wave, and subsequent memory positions are used to store the digital ECG signal as presented to the memory 556 by the analog-to-digital converter 554. In a typical In case, the memory 556 may contain 512 memory locations so that approximately two full seconds of ECG information can be stored in the memory 556.

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So far, the description of Figure 5 has meant how information from the ECG sensor is digitized and stored in the memory 556. Reading of the ECG data from the memory 556 and indication thereof on indicator screens will now be described. The display screen 24 and the slave oscilloscope 28 of Figure 1 can only write one kind of data at a time, so that when the ultrasonic B scan image is displayed on the screens, no ECG information is delivered to the indicator screen and the slave oscilloscope. Only between successful B scan images is the ECG signal indicated. Since it takes about 20 ms to display a B scan image and successive B scans occur at 33 millisecond intervals, approximately 13 milliseconds remain between consecutive B scans to display ECG information and alphanumeric information on the screen.

Immediately after a completed B scan, a control signal of the control control logic 114 of Fig. 1 is sent to the circuits for retention and exposure sequence of Fig. 5 via control line 77. This signal, hereinafter referred to as the image control signal, indicates that the B scan is complete and the display screens are now ready to receive ECG data from the retention circuits. This control signal simultaneously conducts memory 556 in read mode via line 77 to allow stored ECG data to flow from memory 556 via digital-to-analog converter 586 with output line 588 to drive electronics 30 of Figure 1 to provide the Y axis deflection signal for the indicator screen and the slider screen. The image control signal in line 77 also switches the transmit-receive switcher 562 to connect the address of the counter 558 to the memory 556. The image control signal in line 77 also returns the counter 558 such that the first output address of the counter 558 corresponds to the first memory location in memory 556. As the clock 564 advances counter 558 at a rate of about 50kHz, all of the 512 addresses in memory 556 will be read out in the course of approximately 10 milliseconds. which is coupled to the drive electronics 30 in Figure 1 to drive the X-axis of the display screen and the slave oscilloscope.

In order not to display ECG data from previous cardiac cycles that may remain in the upper portions of memory 556, an operation signal is applied to the indicator screen when the count of counter 558 is less than the count of acquisition counter 560. The operation signal is derived by the output signal of lead pair 596 from the image control signal in line 77 of the AND circuit 598 so that the operating signal for the ECG is obtained in line 599. Line 599 is connected via cable 58 to

7700657-5 the visual indication screen 24 of Fig. 1. The digital comparator 594 provides output signal in line 596 only when the count of counter 558 is less than the count of acquisition counter 560. The operating signal occurring in line 599 ensures that only the portion of the signal indicates that corresponding to the ECG in the ongoing cardiac cycle, and the point at the right edge corresponds to the current time in the ECG cycle. Immediately after an R-wave stop has been detected, the track visible on the screen is therefore very short, and as time goes on, this track becomes longer and longer until it meets the entire screen.

The mechanism that provides a runner indication of the displayed ECG signal and its use to control the camera sequence will now be discussed. The use of the runner position switch 95 has been indicated above in the description of Fig. 1. The up counter 612 is used to indicate the runner position. The address of the counter 612 can be either forward or backward by the runner position switch 95. With the ground terminal 616 and with the help of switch 614, the counter advances while ground terminal 618 causes the counter to go backwards as it is driven by the clock 620. As the switch 95 remains in its center position, the contents of the down counter 612 remain unchanged even when this switch is switched 620. The contents of the up counter 612 are compared to the contents of the counter 558 by comparator 622. When the counts for counters 612 and 558 are equal, comparator 622 provides a signal in line 624 which is coupled to visual display screen 24 and slave oscilloscope 28 via cable 58 (Fig. 1). The ECG signal for both the visible indication screen and for the slave oscilloscope is illuminated, whereby the displayed ECG signals for this particular address give a runner marking of this point in the cardiac cycle. By means of the switch 95, the operator can place the runner marker in the position of the heart cycle desired.

One of the main purposes of the runner marker just described is to select and mark the pre-selected point in the heart cycle in which the operator wants a photograph of the B scan. The general sequence of camera work has already been described above. By means of switch 95, the operator places the runner mark at the point in the heart cycle at which a photograph of the B scan is desired. The Photo Sequence Initiator 85 (FIG. 1), when activated by the operator, the camera logic 80 causes the slave oscilloscope screen to become inactive by removing the B scan image signal in line 630 (FIG. 5) and opening the camera shutter as shown in FIGS. C. The time at which

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- The 18 screen is activated is selected at the time the ECG signal reaches point 108 in Fig. 4A. Again with reference to Fig. 5, this time occurs when the count of the acquisition counter 560 is equal to the count of the up counter 612. These two counts are compared by comparator 623 so that when these two counts are identical, an output signal occurs in line 625. The signal in line 625 then activates the display screen under an image whereby the film in the camera is exposed to the selected B scan image. The operation signal for the B scan in line 626 is obtained from the output of logic OR 628. The signals passed to the logic OR 628 are the output signal from the digital comparator in line 625 and the operation signal for photo of B scan in 630 derived in the camera logic .80 in fig. 1st During the camera sequence, the B scan operation signal in 630 is equal to zero so that an operation signal is obtained in '626 only when one is in line 625. The line 626 is connected to the slave oscilloscope 28 via cable 58 (Fig. 1).

The circuits in Fig. 5 provide a logical signal to the camera logic 80 via cable 78 in line 632. The purpose of this output signal is to indicate for the camera control that the ECG has completed its sweep and therefore a new exposure can be made if indicated by the multiple device setting device 98 exposures, or if the exposure sequence is terminated, a simple full ECG signal can be indicated via lines 588 and 592 to allow a full ECG signal to be displayed on the finished film. Once this is done, the shutter can be closed and exposure is complete.

The device, when used to provide a ΊΜ scan, can be used in one of two ways, both of which uniquely interact with the other elements of the device. A unique advantage especially derived from the device of the present invention is due to the fact that the device operator can visually observe the two-dimensional real-time image displayed on the visible display screen 24 while being able to initiate and generate a registreringί record. The sauce has already been highlighted, the known attempts to obtain ΊΜ scans are either approached from near field systems which do not provide a ΊΜ record in the desired find, or are essentially insufficient as they require the diagnostic to perform an IM record in the desired form, or because they are insufficient as they require that the diagnostic perform a TM registration without being able to observe exactly the structure being examined. In essence, full knowledge of what was investigated could only be obtained after such TM registration was entered. In the device of the present invention, the operator may select specific interesting plan for conducting a scan and, in addition, may select specific areas of the sweep sector.

7700657-5 where TM registration is to be performed, the instrument automatically angles the sensing ultrasound beam. While the TM registration is being performed, the operator can observe the B scan image to be sure that the desired structures are being recorded. Another advantage of the present system is that the special section undergoing TM registration can be identified on the B scan image by increasing the illumination of the corresponding part of the image.

Referring to Fig. 3 (also with cross reference to Fig. 2), a schematic block diagram showing details of the operation of the TM registration is shown. The image on the cathode ray tube screen is generally designated 110, and such an image is shown on. the visual display screen 34. Since the image 110 is real-time, the diagnostician can easily angle or position the transducer 12 to obtain the desired structures within the two-dimensional image. As already discussed, the image consists of a series of radial lines 112, each line representing a preselected direction of the ultrasound beam and of the receiver's control means.

The schematic of Fig. 3 comprises a subsystem for switching and control for selecting a single or a series of predetermined lines from the grid of radial lines 112 and representing the selected line (or line sequence) of the TM printer 44 for TM scanning. The TM scan lines can be selectively scanned for part or all of the raster that appears in the B scan image.

In addition to the functions described in connection with Fig. 1, the control control logic 114 provides inputs with address to TM register 116 (Fig. 3) and inputs with addresses to B register 118, and in addition extends these address registers. TM address register 116 contains the address of the radial scan line displayed on the TM printer 44, and the B address register 118 contains the address of the ongoing radial line 112 shown on screen 34. The control control logic 114 also provides control via line 120 to the exchanger 122 and the electronic switch 126 so that when TM address register 116 is coupled to the angular register 125 of the audio beam, the electronic switch 126 couples the video output in line 132 to the TM printer 44. Then, B address register 118 is coupled to the angular address register 125, the video output 132 is coupled to the display screen 34 only.

As the device 10 works to generate the B scan image 110, the exchanger 122 maintains the connection of the B address register to the viral address register 7700657-5

- the audio beam, and the video output signal is coupled to the display screen 34 alone. In this way, the control control logic 114 extends the address of the register 118 by a number for each scanned radial line until all the lines in the selected sector have been completely scanned to provide a frame on the cathode ray tube screen. It then goes back to the original address and repeats the same procedure for subsequent frames. Thus, in this mode of operation, the operator can orient the signal arranger 12 so that the desired cross-sectional plane is obtained where the TM scan is to be performed. In each case, the output of the transducer is controlled and processed by the transmitter / receiver, by the logic logic block 127, is controlled by the angular address register 125 of the sound beam (corresponding to elements 15, 16 and 18 of FIG. 1) and then controlled by the detector and video amplifier 129 , to execute said visual indication.

When the diagnostician is ready for the TM scan, he activates the TM actuator 115 (FIG. 1) for controlling logic 114, which then modifies the operation. In particular, the two address registers 116 and 118 are applied to an address representing a sweep line at the edge of the sector. Via the manual setting means 117, the address of the separate TM line that is desired to be examined can be entered in register 116. Alternatively, logic 114 may be employed to perform TM registration of the selected angle within the scanning sector, that is, an angle of the image 110 including a given number of lines 112. The exchanger 122 is then set to transmit the address of the TM address register 116 to the angular address register 125 for sound beam. A signal from the control control logic 114 via line 130 then initiates the scan line. The video output in line 132 from the amplifier 129 Sr detector and video contains the signals generated by the reflections that occurred along this line, and indications of such reflections are shown by the intensity changes of the corresponding scan lines displayed on the strip printer 44 and the visual indication screen 34. The control logic 114 sets then on the changer 122 so that addresses from B address register 118 are transferred to address register 125 for the sector scanning system. Again, a signal in cable 130 from logic 114 activates block 127, whereby an information line appears in video output 132, which is thereby coupled to visual display screen 34 alone.

The address in register 125 is Sven connected to the cathode ray tube screen 34 via cable 124 to activate a corresponding radial line 112 · on this screen, and a timing signal from logic 114 initiates via cable 130 the writing of this radial line. The B register 118 is thereby increased by

7700657-5 a unit and the exchanger 122 is reset to the TM register and a further scan line is then performed on strip printer 44. When this scan line is preordered, the exchanger 122 is reset to the B register and a new scan line is generated on the cathode ray tube screen 34 where a unit. This process continues until the B register 118 has increased through all addresses for the specially selected sector angle.

After the last scan line with the last address in the B register 118 is completed, exchanger 122 is reset to the TM register. If the system has been employed to perform a TM scan through a selected angle, the address in the TM register 116 is incremented by one unit, and this entire process starts again and is repeated through the next frame of the cathode ray tube. Since the process is repeated for the number of frames equal to the total number of lines at the angle selected for TM registration, the address in TM register 116 will have increased throughout the selected angle, and correspondingly, a complete TM registration has been performed at the strip printer 44, corresponding to the entire section of the real-time image shown on the cathode ray tube screen 34 and comprised by the selected angle. During the entire process of preparing the TM scan, the operator on the visual screen 34 can retain the structures within the entire scanned area. In addition, the radial line undergoing TM registration on the printer 44 is shown as an illuminated radial line on the visual screen because this line is reproduced at a higher repetition rate than the other lines on the screen.

It may be pointed out here that the indicator marks 113 in Figure 2 comprise a series of marks which are spaced apart at intervals corresponding to 1 cm distance in the human body. These indicator marks provide the diagnostic with valuable assistance in assessing the size and distance of structures studied in Figure 110. These indicator marks are generated in the control control logic 114 (Figure 1) and are indicated both on the visual screen 24 and on the slave oscilloscope 28 during the image control signal interval between Bav searches. Thus, they are preserved by the photographic recording of the camera 32 or by the video recording of the video recorder 40. Since the image size may vary depending on the magnification of the photographed or video recorded image, it is important to have a suitable calibration that relates the final image to the actual size of the video. original structures. The size control 156 for the sector can also be used to change the size of the displayed image, however, the control control logic 114 taking this size information into account and providing the correct scale of the indicator marks 113.

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As a further embodiment of the present invention, the two-dimensional image shown in real-time, and thus the resulting derived recordings by the present system, may undergo various image manipulation procedures which enable such useful results as varying the resolution of the image or enabling the operator to focus his or her interest on certain specified parts of the image, and so on. Referring to FIG. 1 For example, the control control logic 114 provides input signals to the drive electronics 30 as well as to transmitters 16 and receivers 18 which are connected to transducer 12.

An input to the control control logic 114 is also obtained from a receive amplifier control 150 which is in turn influenced by the operator's setting of the depth gain control 152. The latter allows the operator to set the receive gain to increase this only when the receiver processing of the particular image 110 is processed. The net result of this arrangement for the operator's consideration is that the operator can set the system so that lower portions of the image, or upper portions, or selected areas in the upper or lower portions are made more intense.

By means of the sector gain control 128, the operator can also set the system to tune the gain of preselected angular sections of the sector to strongly illuminate the desired structures being imaged. This angular gain setting also allows the operator to compensate for reduced sensitivity of the transducer when detecting signals from large scan angles. By appropriately adjusting the sector gain control 128, a uniform image can also be obtained at very large sector angles.

The control control logic 114 similarly receives inputs from the rejection control 154 and from the data compression control 155 '. The rejection check 154 acts to establish a threshold level for rejecting signals in the receiver 18, i.e., thereby achieving noise rejection as is known in the receiver technology. Compression control 155 varies the characteristics of the receiver gain to allow a non-linear mode of operation, that is, the output of the receiver in the direction of the screen can be made proportional to the logarithm of the input signal, thereby enabling scale expansion in the region where the signal is of greatest interest. Techniques of this kind are once again well known in the art of sealing therapy.

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In addition to the above-mentioned controls relating to image manipulation, there are two additional controls which are useful in system 10. These are light intensity control 157, which essentially acts to increase or decrease the overall intensity of the display by applying an appropriate DC bias to the grid of the cathode ray tubes for the various screens, and in addition there is size control 156 for the sector which allows the operator to operate. their desire barricades the angle of the sector that appears in the scan. Thus, in a typical case, the angle investigated can be varied, band settings such as 20, 40.60 and 80 degrees. According to this embodiment of the invention, the size control 156 acts through the control control logic 114 to select a set of radial raster lines 112, the selected group of lines serving to define the set sector angle. In this context, it should be understood that a relatively large number of these radial lines are used to define the sector scan in the present system. As already mentioned, in the typical case 64 such lines may be present when a maximum width of 21 cm has been selected. Regardless of the sector size set in the system, the total number of such lines will remain the same when the system is set to its maximum width of 21 cm. (Note that any maximum width can be selected. When imaging organs in the human body, 21 cm represents a normal maximum). Thus, it is obvious that the total number of available radial lines is considerably greater than the aforementioned 64. In a typical device, in fact, 256 such lines are available to the system, but at most 64 such lines are selected from the total possible number of 256, according to settings of the size control 156 for the sector. The selected group defines the particular sector and is fed sequentially to the address register 125 as shown in Figure 3 to effect the sector scan. The significance of the most recently described operation is, of course, that the definition obtained in the narrower sector sweep is greater than in the wider sweep genoi that the total number of grid lines remains the same. Accordingly, this embodiment of the invention enables the operator to increase the definition of the image by reducing the angle of the sector scan after first locating the area of ​​interest, whereby larger structural details appear on the displayed beam as well as on the recordings that can be performed by the system 10 and which corresponds to the displayed image.

In one embodiment of the possibilities for image manipulation in system 10, a range control 140 is provided which is coupled to control control.

7700657-5 logic 114 via line 142. Reach control 140 includes adjustable elements that allow the system operator to vary the maximum range or depth of the sector scan to adapt the system for use with patients with different physical conditions. For example, the range control can be set to allow study at depths up to 21 cm, 7 or 14 cm from the transducer. The more limited depths are suitable when examining cardiovascular structures in a child. The range control 140, which operates via the control control logic 114, which as described controls the transmitter 16, the receiver 18 and the switching and logic circuits 15 via the control cables 144, 146 and 148, enables these results by varying the speed of the control pulses of the transducer element.

The range control allows a greater number of radial lines to be used when investigating shallow depth structures. In the examples above, in the typical case, 64 lines are used to search for structures up to 21 cm deep. By reducing the depth to 14 or 7 cm, a total of 96 and 192 lines can be used. The greater line density obtained with the submerged depth allows greater structural details to appear in the images shown.

While the present invention has been described in detail with reference to specific embodiments, it should be understood that a variety of variations of the invention are possible to one skilled in the art, however, variations will remain within the scope of the present invention. Accordingly, the invention should be interpreted broadly and limited only by the scope and spirit of the following claims.

7700657-5 is