GB1564610A - Apparatus suitable for effecting ultrasonic diagnosis of a patient - Google Patents

Description

(54) APPARATUS SUITABLE FOR EFFECTING ULTRASONIC DIAGNOSIS OF A PATIENT (71) We, VARIAN ASSOCIATES, INC., of 611 Hansen Way, Palo Alto, California 94303, United States of America, a corporation organized under the laws of the State of Delaware, United States of Amenca, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus suitable for effecting ultrasonic diagnosis of a patient.

Over the course of the last two to three decades, ultrasonic technology has played an ever-increasing role in medical diagnostics. An area of special interest for present purposes is the use of such technology for identifying and examining cardiac structures.

Techniques wherein successive echoes provided by at least one structure within a region of a patient (e.g. within the heart of a patient) are converted into curves indicative of the movements of said at least one structure are herein defined by the "TM" or "Time-Motion scanning" or "Time-Motion recording" when a chart record is obtained.

As far back as at least 1953, Edler and Hertz described such techniques.

Pursuant to these techniques. a narrow ultrasonic sound beam is projected into the regions of the heart from a surface transducer that may, e.g., be positioned as to propagate the beam between the ribs. As a pulse of ultrasonic energy is propagated inwardly through the various structures.

including heart wall. valves, and the like.

some of the energy is reflected back toward the transducer at the boundaries between the various structures. This reflected energy is then detected, amplified and. as desired.

displayed on an oscilloscope or recorded on a strip chart.

The type of information secured by the aforementioned techniques can be of great diagnostic value since the structures being examined change in a characteristic way in certain diseases of the heart, and a skilled physician can readily determine the presence of such changes from examination of a properly obtained display or recording of the type mentioned.

Insofar as the TM scan is concerned, it may be observed that up until recently, a major problem inherent in the applicable apparatus was that the operator was, in essence. 'flving blind". This is to say that the only information that such operator had regarding whether the transducer was properly oriented for the structures that he was trying to observe, was obtained by looking at the data that was being recorded on the display scope or on the recorder, Pursuant to such approach, the operator was required to tilt or angulate the transducer to cover and seek out a range of structures on which he desires to obtain recordings. Thus, the only feedback he had regarding whether the recording being made actually included the structures desired to be observed was obtained after the fact.

Recently apparatus has been reported wherein a TM scan may be obtained from a B-scan obtained from a near field array. The difficulty is that the TM scan images obtained from a near field array are not in a form familiar to diagnosticians and for such reasons are not readily correlated to the structures examined.

It may nextly noted that a number of ultrasonic imaging systems have recently been reported -- and in some instances, have become available for use by researchers -which systems enable a two-dimensional image. e.g.. of a cardiac structure. to be generated and observed in real time. A system of this type utilizing phased array principles to steer and focus an ultrasound beam provided by an array of transducers, is described by Thurston and von Ramm in "A New Ultrasound Technique Employing Two-Dimensional Electronic Beam Steering", appearing in Acoustical Holography, Volume 5, P.S.Green, Editor, Plenum Press, 1974. Additional aspects of systems based upon such apparatus are set forth at Volume 6 of the mentioned Acoustical Holography series at page 91, in an article by von Ramm, Thurston, and Kisslo entitled "Cardiovascular Diagnosis With Real Time Ultrasound Imaging". Reference may also be usefully made to J.C.Somer, "Electronic Sector Scanning for Ultrasonic Diagnosis", appearing at page 153 of Ultrasonics for July, 1968.

The real time imaging systems above mentioned, and others as have been recently described by additional researchers, have indeed provided useful new tools for the medical diagnostician, in that, for the first time, it has become practical to directly observe an extended expanse of the heart functioning in real time, or substantially simultaneously with the functions occurrence. At the same time, however, such systems have represented but an initial approach to an extremely complex diagnostic environment; and the reported systems have been markedly lacking in the sophistication and flexibility that the diagnostician requires. Numerous of these prior art systems, for example, have generated low resolution in the images thereby provided, and have not included capabilities for manipulating the image to concentrate upon or examine certain specified regions within the heart or associated cardiovascular structures. Of perhaps greater significance is the fact that these prior art devices have failed to enable a diagnostic interrelationship between the B-mode display which they provide, and the various additional diagnostic read-outs commonly employed by the cardiologist, for example, the well-known ECG, the phonocardiogram, and the already mentioned TM mode display and recordings.

According to the present invention. there is provided apparatus, comprising means for transmitting ultrasonic sound into a region of a patient and receiving back ultrasonic sound from said region, said means comprising transducer means for generating said transmitted ultrasonic sound; first display means adapted for providing from said received ultrasonic sound, a visual display comprising a fan shaped, two-dimensional, real-time image of said region. said image comprising a plurality of linear image elements; ECG input means for connection to said patient to provide an ECG signal; and means for providing from this ECG signal an ECG visual display in at least substantially real time;wherein said transducer means comprises a plurality of transducer elements.

Said apparatus of the present invention can be embodied in any desired way. Some preferences for embodying said apparatus of the present invention are indicated by the subordinate claims contained in the claims appended to this specification. Especial references should be made to said appended claims, because they also form part of the disclosure of the present invention.

It will be appreciated from said appended claims and the description given later below of the accompanying drawings that a said apparatus of the present invention can provide a display and recording system for effecting ultrasonic diagnosis of a patient.

Such a system is particularly applicable to cardiology, and a said apparatus of the present invention is capable of directly displaying for operator investigation a high resolution and readily manipulatable real time image of cardiac structure.

A said apparatus of the present invention can comprise means for enabling simultaneous or independent display of an ECG, as indicated by the claims appended to this specification and by the description given later below of the accompanying drawings.

In this respect, attention should be paid to U.K.Patent application No. 34396/76 (serial No. 1564609) from which this application is divided, and which refers to apparatus that can provide an ECG visual display. The expression "ECG" means according to the context herein, either prior art apparatus for providing electrocardiographic information (i.e. heart information), or an electrical signal which is provided from electrocardiograph apparatus. If desired, a said apparatus of the present invention can include means for enabling simultaneous or independent display of a phonocardiogram, as indicated by the claims appended to this specification and by the description given later below of the accompanying drawings.

Said fan shaped image provided by said apparatus of the present invention can provide a fan shaped display in real time of a cardiac structure or the like. thereby enabling a so-called B-mode display of such a structure.

In one preferred embodiment of said apparatus of the present invention, said transducer means comprises a phased array comprising a plurality of elements arranged and connected to a transmitter and receiver, whereby the transmitted pulses of ultrasound are so phased as to steer the emitted sound beam in a desired direction. Adjustable delays can be provided in each receiver channel so as to enhance reception from the same direction as the transmitted sound beam. By suitably controlling the timing of transmission by the transducer elements and the adjustable delays of the separate receiver channels, the beam can be steered to any desired angle of a fan-shaped sector. Operation of the steered array is such that a plurality of radial lines defining the fanshaped display can be successively generated with a relatively high number of such radial lines, typically of the order of 64 such lines, being utilized in the course of generating the entire fan-shaped sector. The set of such lines are generated over a short period, typically of the order of 1/30th of a second, whereby the corresponding display on the cathode-ray tube (CRT) is a high resolution, substantially real time (or "high speed") image of the heart and related cardiovascular structures, the said visualization being in the so-called B-mode, i.e., one wherein variations of the acoustical impedance of the tissue are translated into brightness variations on the CRT screen.

The use of said fan shaped, visual display offers imPortant advantages in the visualization and measurement of cardiovascular structures. It permits visualization of the cardiac area through the relatively small access that is available between the ribs.

Means can be provided in a said apparatus of the present invention so as to vary the sector size of the fan-shaped area to achieve a desired angular configuration varying e.g. between 20 and 80 degrees.

Since the same number of scane lines can be utilized in each instance, such variation can enable increased resolution where a particular portion of the image is deemed of special interest.

Means can be provided in a said apparatus of the present invention so as to vary the repetition rate of scan lines and enable depth control of the displayed sector scan.

By this technique, examination of less deep portions of the cardiac structure can be achieved with a corresponding increase in the line density. For example, when examining structures near the maximum range of 21 cm a total of 64 lines can be used. By restricting the maximum depth to 7 cm a total of 192 lines might be used. providing superior sensitivity while examining infants for example.

Data obtained by apparatus of the present invention can be varied to compress portions of same, i.e.. to enable non-linear processing; and the system may include means for rejecting signals below a certain amplitude, e.g. to enable noise rejection.

Means can be provided in a said apparatus of the present invention so as to vary the gain of reception from various sectors of the examination zone. In this manner. it is possible to compensate for regions of greater attenuation that may occur in certain regions of the body.

A said apparatus of the present invention can provide a fan shaped, visual display on a CRT accessible for operator viewing. A slave scope can be driven in synchronism with the fan shaped, visual display, and photographic camera means can be positioned to enable photographs to be directly obtained from the slave scope. The slave scope can be associated with a vidicon, the outputs of which can be provided to both a video recorder and to a video monitor, for enabling auxiliary or remote viewing of the display.

A said apparatus of the present invention include said ECG input means. The ECG proper can be displayed on said first display means that provides the fan shaped, visual display. Means can be provided for enabling the generated ECG pattern to persist for a period sufficient to enable the operator to identify significant features thereof.

A said apparatus of the present invention can include an operator movable cursor (e.g. a suitable mark) as mentioned earlier above, and may be positioned at a desired point on the ECG record. This operation serves a highly significant function during preparation of photographs. In particular, means can be provided which enable production of a photograph corresponding to the real time image at the point in the cardiac cycle identified by the cursor. This enables the operator to obtain a photographic readout at any precise point in the cardiac cycle which he may deem of pertinence to his examination.

A said apparatus of the present invention can include a keyboard input associated with suitable alphanumeric character generator means, so as to enable insertion of alphanumeric and other information upon the fan shaped visual display. Information may be thereby entered by the operator repecting such matters as patient identification, date of the examination, and other data of interest to the diagnostician or the institution effecting the patient testing. In addition. instrument parameters and related data can be automatically displayed, e.g.

data respecting the point of the ECG cycle of which the photograph is indicative. Information of the latter type may be correlated with the aforementioned cursor position which can also be provided to the display in the form of timing data specifying the time displacement from the R-wave or other significant datum in the ECG cycle.

A clock display may be superimposed upon said first-display means, so as to provide a continual record, which can extend down to 1/100's of second, whereby each full frame (e.g. 1/30 sec.) carries a distinct time identification. This type of information is significant for the aforementioned photographs. and is of special value in the course of interpreting the video recordings which can be secured by the present system.

The securing of the aforementioned categories of identifying and related data is of significance, not only for normal recordkeeping purposes, e.g. to enable ease of correlation of photographs and video recordings with patient records or so forth.

Moreover, the said information is significant in connection with medico-legal problems and/or for regulatory purposes, e.g. in order to conform to such requirements as may be imposed by the hospital or other institution utilizing the equipment or by state or federal agencies.

The present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is an electrical schematic diagram in block form and sets forth apparatus incorporating one embodiment of apparatus in accordance with the present invention.

Figure 2 is a schematic plan view of a fan shaped, visual display provided by the apparatus of Figure schematic 1.

Figure 3 is an electrical schematic block diagram, illustrating operation in a TM mode of the apparatus of Figures 1 and 2, as well as indicating some aspects of the sector generation techniques; Figures 4A, 4B and 4C are graphs, setting forth certain aspects of the sequence effected during making of photographs by apparatus of Figures 1 to 3 and Figure 5 is an electrical schematic block diagram illustrating the electronic persistance and exposure sequencing circuits shown as block 56 in Figure 1.

In Figure 1 display and recording apparatus 10 operates upon ultrasonic principles.

and is intended primarily for use in effecting diagnosis of cardiac and cardiovascular conditions, although it will be evident to those skilled in the present art that the apparatus 10 is useful in other diagnostic applications in that the apparatus 10 can provide useful information in these further applications.

However, because of its primary application to cardiac and cardiovascular diagnostics.

the apparatus 10 applied to cardiac and cardiovascular diagnostics will be emphasized in this specification.

A sonic transducer 12 comprised by apparatus 10 is operatively associated with a patient 14, so as to enable the ultrasonic sound beam thereby produced to be projected into the regions of the heart and related structures. Thus transducer 12, as is known in the present art, can be positioned so as to propagate its output between the ribs of the patient.

Although various transducer configura- tions as are known to be useful in conjunction with generation of two-dimensional images can be used with the invention.

transducer 12 comprises a phased array consisting, for example, of a plurality of elements such as for example 32 piezoelectric elements arranged in a compact linear arrangement. In a typical instance, each such element may have a length of 12 mm, a width of 0.3 mm and center-to-center spacing between adjacent elements of 0.4 mm.

Generally the transducer 12 should be of a physical size to enable effective use in connection with a human, as for example propagation of ultrasound between ribs to enable display of the heart area. The thickness of the specific transducer element utilized is determined by the operating frequencies, and can typically be of the order 0.7 mm where a frequency of 2.5 MHz is utilized.

Transducer 12 is connected through switching and logic means 15 to a transmitter 16 and a receiver 18, and transmitted pulses at the desired ultrasonic frequency are phased by the timing sequence of the voltages applied to the individual transducer elements, so as to steer the emitted sound beam in the desired direction. Adjustable delays are provided in each receiver channel. which enhance the reception from the same direction as the transmitted sound beam. By controlling the timing of the voltages applied to the transducer elements and the adjustable delays of the separate receiver channels, the beam is steered to desired angles of fan-shaped sector 25.

operation of the steered array, the phasing, and the delay sequences, are effected so that a plurality of radial lines defining the fanshaped sector 25 are successively generated with a relatively high number of such radial 'lines, typically in the range of 64 to 256, being utilized in the course of generating the entire sector. A set of such lines is generated over a short period, typically of the order of 1/30th of a second, whereby the corresponding displayed image 110 (Figure 2 or Figure 3) on a CRT display screen (24 in Figure 2 or :34 in Figure 3) is a high resolution, real time image of the heart and related cardiovascular structures, the said visualization being in the so-called B-mode, i.e., one wherein tissue impedance variations are translated into brightness variations on the CRT screen.

Further details regarding the signal processing techniques utilized in connection with transducer 12 to generate the mentioned fan-shaped sector 25 (Figure 2), are set forth in our U.K. Patent application No.

32 474/76 (1557218).

The output from receiver 18 proceeding via line 20. is provided in parallel to three instrumentalities 24, 28, 44. A first such parallel output is provided via line 22 to a visual display 24. which as mentioned above typically takes the form of a conventional CRT screen directly viewable by the system operator. The display 24 may however, comprise other display devices such as for example a plasma display panel.

Via line 26, a second parallel output from receiver 18 is provided to a slave scope 28.

Slave scope 28 and display 24, are operated in synchronism by drive electronics 30, which if the CRT's are employed provides the required deflection voltages of each of the CRTs. In consequence of this arrangement, the precise display being provided at any given time for operator viewing at display 24 is also simultaneously present at slave scope 28. Operatively associated with slave scope 28 is a reproductive means which may comprise a photographic camera 32 mounted in spaced relationship from the CRT screen of the slave scope so as to enable direct photographing of that screen at selected times. An output image is taken at 34 from slave scope 28 and provided to a conventional vidicon 36. The vidicon 36, in turn, provides an output 38 to a video recorder 40. A video monitor 42 may be provided for monitoring the information being thus recorded. These last several elements and their mode of operation are well known in the art, and therefore further details of their functions and interconnections are not provided.

A third parallel output from receiver 18 is provided via line 42 to a TM recorder 44.

TM recorders are per se well-known to those familiar with the art of cardiac diagnosis. In the usual application of these devices in echo cardiography, the sound modifying characteristics existing along a linear direction of structural examination are recorded on a strip output 46 as the said strip advances with time. In this sort of arrangement, the resultant pattern is thus indicative of the displacement with time of the structural features being observed by the echoing techniques. The TM recorder 44 is of this same type; and while the manner in which it interacts with the remaining elements of the apparatus 10 produce new and highly unexpected results ( as will be hereinbelow discussed), the recorder 44 per se may be of a conventional design. For example, a recorder Model 1856 from Honeywell may be utilized in the present system, as may several other devices of this type as are known in the art.

An ECG sensing and recording means is contained by apparatus 10. In particular. an ECG sensor 50 is provided. which may constitute the usual electrodes and related paraphernalia operatively associatable with the patient being examined. The output from sensor 50 is provided to an ECG amplifier 52, after being processed by electronic persistence circuits of block 56, is provided via line 58 to visual display 24. as well as to slave scope 28. It will be appreciated that the ECG trace, as same develops on the CRT screen of display 24, will be generated in real time and would in principle therefore, only be visible as a point of light progressing across the screen. In order to render the trace useful for operator analysis, it is necessary to effect persistence of the developing trace for at least a portion of the ECG cycle sufficient to enable operator analysis. The electronic persistence circuits of block 56 are provided to effect such result. Apparatus for providing this feature is indicated in Figure 5 and is described more fully below. Essentially the persistence circuits function to refresh a portion of the ECG trace for a desired period. For example referring to Figure 2, the point 103 may be assumed to represent the developing point of the trace, i.e., the point being generated in real time on the CRT screen 102. The portion of the trace indicated at 101 may, however, be rendered persistent by the circuit block 56, so that this portion of the developing trace remains visible for examination by the operator.

The apparatus 10 contains a phonocardiograph capability or other physiological detecting and recording devices. Thus, a microphone 60 is provided, the input of which is connected to a phonocardiograph 61 and thence via auxilliary amplifier 62 and line 55 to the same electronic persistance circuits of block 56 as are used for the ECG system so that the phonocardiograph output can, if desired, be placed open visual display 24 and recorded, photographed or so forth, by the various recording elements of the system. In similar fashion. other physiological inputs as indicated by auxilliary physiological input block 63 may be amplified by amplifier 62 and provided to circuits of block 56. For example, the auxilliary input 63 may comprise a respiration monitor.

An operator-actuated keyboard input 64 is contained by apparatus 10, so as to enable insertion onto the various displays identification data and additional important information. The keyboard 64 actuates an alphanumeric character generator 66 and/or a clock 68, which provide time data and various alphanumeric identification data through the lines 70 and 20 to the visual display 24 an slave scope 28. By referring to Figure 2, it may thus be seen that information of the type just discussed may be inserted by the operator upon the display 24. For example, patient identification data bv number, name, or so forth, appears at li)4 and operator identification appears at 105. the date of examination at 106, and time information at 107. and camera sequence information at 109. The data at 111 comprise the elapsed time from the R-wave peak of the ECG to the time the camera effects a picture of the B-scan data as explained more fully below.

The types of information indicated serve several important purposes. In the simplest instance, the identification data, as they will appear on photographs and video recordings obtained by the apparatus 10, enable direct identification of the records to the patient, thereby avoiding any possibility of error. The time information has indispensible significance in connection with the video recordings effected by video recorder 40.

The time information in particular, because it is normally provided in 100ths of a second, uniquely identifies each frame on the CRT display 24, (i.e., each frame persists for 1/30th of a second). Hence, study of the video recording together with the time information, can enable precision determination of the motion characteristics of the structures depicted.

It should also be noted as significant, that the various data just mentioned are deemed to be of ever-increasing importance from a medico-legal and regulatory agency viewpoint. Thus, in many instances, hospitals and similar institutions, by virtue of their own internal regulations or requirements imposed upon them by insurance companies or so forth, require or at least desire, accurate data of the type mentioned, for use in possible legal proceedings based upon diagnosis; and similarly, state and/or federal regulatory agencies are increasingly placing stringent requirements upon the identification data associated with medical records.

The apparatus 10 contains camera means 32, which may be of any conventional construction. Various models of the wellknown "Polaroid" cameras ("POLAR OID" is a registered trade mark) as well as display type xerographic cameras, as for example commercially available from Varian Associates ("VARIAN" is a registered trade mark) are well suited for the present purposes. In accordance with the techniques utilized in apparatus 10 so as to enable photographs of displays at slave scope 28.

camera logic 80 is provided which includes suitable logic circuitry for activating camera actuator 82, which, by electro-mechanical or similar means, effects tripping or triggering of the camera 32 to effect an exposure at a desired time. The operator selects the point in the ECG display at which the photographic exposure is to be effected, with the aid of camera logic 80 and electronic persistance and exposure sequence circuits 56. The latter in particular, acting through cursor positioning switch 95, moves a cursor mark to any preselected region of the ECG display 101, such cursor indication being for example a brightening of the ECG display at the desired point. Such a point is indicated in Figure 2 by point 108.

The timing of the camera sequence is explained with the aid of Figures 4A to 4C.

When a photograph is desired, camera logic 80 is activated by the operator initiating the photo sequencer 85. After activation, indicated at time 83 on the ECG 100 of Figure 4A, camera logic 80 immediately blanks the screen scope 28 by receiving an unblanking signal on line 81 from Master Control logic 114 and preventing it from being applied via cables 78 and 79 to slave scope 28. The blanked and unblanked condition of slave scope 28 is depicted in Figure 4B. The camera logic 80 through camera actuate 82 opens the shutter of camera 32 as depicted in Figure 4C. The apparatus 10 then continues to operate with the screen of the slave scope 28 blanked until the next R-wave (Figure 4A) is detected by electronic persistant and exposure sequence circuits 56.

When the horizontal position of the ECG arrives at the cursor marker 108 at time 89, a trigger signal is sent from circuits 56 to slave scope 28, to unblank the B-scan so as to provide one frame of cardiac data on slave scope 28. This unblanking period lasts about 20 milliseconds which is adequate to display and record one frame of B-scan data.

The slave scope 28 is then blanked (at 93 in Figure 4B) until approximately one second later (at 97) when another unblanking occurs; but this time only the ECG signal on slave scope 28 is unblanked so that this information is then presented to the camera 32. The system is then blanked again (at 99) and the camera shutter closes, after which the display is again <RT volts. These signals are then digitized by the analog-to-digital converter 554 and fed into the random access memory 556. The address of memory 556 is determined either by the display counter 558 or by acquisition counter 60. Duplexer 562 selects which counter is coupled to the memory 556.

During the acquisition phase of the ECG signal, duplexer 562 provides coupling only from the acquisition counter 560 to control the address of memory 556. The address of counter 558 is derived directly from clock 564 and the address of counter 560 is derived by dividing the frequency of clock 564 by a divider 566. In a typical example, clock 564 may run at a frequency of approximately 51 kHz and divider 566 may typically divide this frequency by 256 leading to a frequency of approxlmatelfy 200 Hz as the input frequency to counter 560. Counter 560 will continue to advance as it receives pulses from divider 566 until the counter is filled, that is until a most significant bit output is obtained on line 568. An output on line 568 resets flip-flop 570 so that the enable signal on line 572 is set to zero thereby halting further counts on counter 560. Counter 560 maintains this state until the next R-wave is detected by peak detector 574. When an R-wave is present, peak detector 574 applies a voltage on line 576 to AND gate 578. If acquisition counter 560 is full a most significant bit is present on line 568 and flip-flop 570 maintains a positive signal on the Q output 580. The combination of this positive output on 580 and the positive detector output from peak detector 574 activates gate 578 to produce a positive output on 582 which is applied to the reset input of acquisition counter 560 and the set input of flip-flop 570. Acquisition counter 560 then advances as it receives pulses from divider 566. By the above-described means the address of random access memory 556 is set to its lowest address at the peak of the R-wave, and subsequent memory locations are used to store the digital ECG signal as it is presented to memory 556 by analog-todigital converter 554. Typically memory 556 may contain 512 memory locations so that approximately 2 full seconds of ECG information would be stored within memory 556.

So far the description of Figure 5 has been directed toward how information from the ECG sensor is digitized and stored in memory 556. The reading of the ECG data from memory 556 and displaying it upon the output displays will now be described. The visual display 24 and slave scope 28 of Figure 1 are capable of writing only one piece of date at a time on the display screen, so that while the ultrasonic B-scan image data is being displayed upon the screen. no ECG information is presented to the display scope 24 and slave scope 28. It is only between successive frames of the B-scan picture that the ECG signal is presented to the display. Since it takes approximately 20 ms to display one frame of B-scanned information and successive B scans occur at 33 millisecond intervals, one has approximately 13 milliseconds between successive B scans to display the ECG information and alphanumeric information upon the screen.

Just after a B-scan has been completed, a control signal is supplied by the master control logic 114 of Figure 1 to the persistence and exposure sequencing circuits (Figure 5) via control line 77. This control signal hereafter identified as "frame overhead" indicates that the B-scan has been completed and that the displays are now ready to receive the ECG data from the persistence circuits. This control signal via line 77 simultaneously sets the memory 556 to the read mode permitting the stored ECG data to flow from memory 556 through the digital-to-analog converter 586 with output line 588 to the drive electronics 30 of Figure 1 to provide the Y axis deflection signal for the display scope 24 and slave scope 28. The frame overhead signal on line 77 also switches duplexer 562 to couple the address of display counter 558 to memory 556. The frame overhead signal on line 77 also resets the display counter 558 so that the initial output address from display counter 558 corresponds to the first memory location in memory 556. As clock 564 is advancing counter 558 at approximately a 50 kHz rate, all 512 addresses in memory 556 will be read out in approximately a 10-millisecond period. The digital-to-analog converter 590 also receives the address from display counter 558 and converts that address to an analog signal on line 592 that is coupled to drive electronics 30 of Figure 1 to drive the X axis of the visual display scope 24 and slave scope 28.

In order not to display ECG data from previous cardiac cycles that may remain in the upper part of memory 556, an unblanking signal is applied to the display scope 24 when the count of display counter 558 is less than the count at acquisition counter 560.

The unblanking signal is derived by applying the output signal on line 596 of digital comparator 594 with the frame overhead signal on line 77 in AND circuit 598 to produce the ECG unblank signal on line 599. Line 599 is coupled through cable 58 to visual display 24 of Figure 1. Digital comparator 594 produces output on line 596 only when the count of display counter 558 is less than the count of acquisition counter 560.

The blanking signal which appears on line 599 ensures that only that part of the ECG will appear on the display screen 24 that corresponds to the ECG in the current cardiac cycle and the point at the right-hand edge corresponds to the current time in the ECG cycle. Early in time after an R-wave peak has been detected, the trace visible on the screen 24 is thereby very short and as time progreses this trace becomes longer and longer until it fills the entire screen 24.

The mechanism to provide a cursor in dicator upon the displayed ECG signal and its use in controlling the camera sequence will now be considered. The use of the cursor positioning switch 95 has been indi cated above in the description of Figure 1.

Updown counter 612 is used to indicate the position of the cursor. The address in counter 612 can either be advanced in the forward direction or in the reverse direction by means of cursor positioning switch 95. By grounding terminal 616, by means of switch 95 the counter 612 will advance whereas grounding terminal 618 will cause the coun ter 612 to advance in the reverse directon as it is driven by clock 620. When the switch 95 remains in its center position the contents of up-down counter 612 will remain unchanged even though it is coupled to clock 620. The content of up-down counter 612 is compared with the content of display counter 558 by digital comparator 622. When the count in counters 612 and 558 are equal comparator 622 will put a signal on line 624 which is coupled to visual display 24 and slave scope 28 through cable 58 (Figure 1). The ECG signals of both the visual display scope 24 and slave scope 28 are brightened, the displayed ECG signals for that one address thereby providing a cursor indication of that point in the cardiac cycle. By means of switch 95 the operator can place the cursor marker at any desired point in the cardiac cycle.

One of the main purposes of the cursor marker just described is to select and indicate the pre-selected point in the cardiac cycle at which the operator desires a photo graph of the B-mode scan. The general sequence for camera operation is already described above. The operator, by switch means 95, places the cursor mark at the point in the cardiac cycle at which a photo graph of the B-scan is desired. The photo sequence initiator 85 (Figure 1), when acti vated by the operator, causes camera logic 80 to blank the screen of the slave scope 28 by removal of the photo B-scan unblank signal on line 630 (Figure 5) and opens the camera shutter as depicted in Figures 4B and 4C respectively. The time at which the screen 28 is unblanked is selected to be the time at which the ECG signal arrives at point 108 of Figure 4A. Referring now again to Figure 5, this time occurs when the count of acquisition counter 560 is equal to the count in up-down counter 612. These two counts are compared by digital comparator 623 so that when these two counts are identical an output occurs on line 625. The signal on line 625 then unblanks the screen of slave scope 28 for one frame and thereby exposes the camera film to the selected B-scan frame. The B-scan unblanking signal on line 626 is obtained from the output of logical OR 628. The inputs of logical OR 628 are the digital comparator output signal on line 625 and the proto B-scan blanking signal on 630 which was derived in camera logic 80 of Figure 1. During the camera sequence, the proto B-scan unblanking signal on 630 is zero so that an unblanking signal on 626 is obtained only if one is present on line 625. Line 626 is coupled through cable 58 (Figure 1) to slave scope 28.

The circuits of Figure 5 put out a logic signal to the camera control logic 80 via cable 78 on line 632. The purpose of this output signal is to indicate to the camera controller that the ECG has finished its sweep and therefore another exposure can be taken if so indicated by multiple exposure set 98 or if finished a single complete ECG signal can now be displayed via lines 588 and 592 permitting a full ECG signal to appear on the final film. Once this has been accomplished, the shutter can be closed and the frame will be complete.

A unique advantage arises by virtue of the fact that the operator is able visually to observe the two-dimensional real time image provided upon visual display 24 at the same time he initiates preparation and generation of a TM recording. As has' already been pointed out, the prior art, approaches to the production of TM recordings were either made from near-field arrays which do not produce a TM recording in the accepted format or were basically deficient in requiring the diagnostician to effect a TM recording without the benefit of certainty regarding precisely what structure was being investigated. In essence, only after such TM recording was obtained, could the investigator actually be apprised of that which he was investigating. With apparatus 10 the operator is able to select specific planes of interest for effecting a TM scan and, moreover, to select specific areas of the scan sector for which the TM recording is to be carried out, the apparatus 10 automatically angulating the probing ultrasonic beam.

While the TM recording is being made, the operator may simultaneously observe the B-scan display to ensure the desired structures are being recorded. Another feature of apparatus 10 is that the particular section being recorded on the TM recorder may be identified on B-scan display by an increase in brightness of the corresponding part of the image.

Referring to Figure 3 (and cross referencing to Figure 2), a schematic block diagram appears setting forth details of the TM recording modes of operation. A CRT screen image is generally indicated at 110, such image being provided at visual display 34. Because image 110 is in real time, the diagnostician can readily angulate or posi tion transducer 12 to obtain the desired structures within the two-dimensional im age. This image, as already discussed, is comprised of a series of radial lines 112, each line representing a preselected direc tion of the ultrasonic beam and the receiver steering pattern.

The schematic arrangement of Figure 3 provides a switching and control subsystem which will select one or a series of predeter mined lines from the raster of radial lines 112, and present the selected line (or in sequence the lines) to the TM strip chart recorder 44 for TM scan. The lines for the TM scan may be selectively swept through a part or all of the entire range of the raster set occuring in the B-scan picture.

In addition to functions described in connection with Figure 1, master control logic 114 provides inputs to address the TM register 116 (Figure 3), and to address the B register 118, and further, increments each said address register. TM address register 116 contains the address of the radial scan line presented on TM recorder 44, and the B address register 118 contains the address of the current radial line 112 displayed on visual display 34. Control logic 114 also provides control through line 120 to duplex er 122 and electronic switch 126 so that when TM address register 116 is coupled to beam angle address register 125, electronic switch 126 couples the video output on line 132 to TM recorder 44. When B address register 118 is coupled to the beam angle address register 125, the video output line 132 is coupled only to visual display 34.

In operation of apparatus 10 for genera tion of the B-mode image 110, duplexer 122 maintains the coupling of B address register to the beam angle address register 125 and the video output is coupled only to visual display 34. In this mode, control logic 114 increments the address contained in register 118 by one number for each radial line 112 that is scanned, until all of the lines of the selected sector have been swept completely to generate one frame on the CRT display.

It will then go back to the initial address and repeat the same process for succeeding frames. Thus, in this mode of operation. the diagnostician can orient transducer 12 to obtain the desired cross-sectional plane for which he wishes to obtain his TM-mode scan. In all instances the transducer outputs are controlled and processed by the trans mitter/receiver and switching logic block 127, are controlled by beam angle address register 125 (corresponding to elements 15.

16 and iWin Figure 1), and then by detector and video amplifier means 129, to enable the said visual display 34.

When the diagnostician is ready for a said TM scan, he activates T.M. activator means 115 (Figure 1) for controlling control logic 114 which then modifies the operation. In particular, both address registers 116 and 118 are initialized to an address representing a scan line at the edge of the sector. Via manual set control 117 the address of a single TM-line sought to be examined may be set into register 116; or control logic 114 may be set to effect TM recording of a selected angle within the scan sector; i.e. an angle in image 110 comprising a given number of radial lines 112. Duplexer 122 is then set to transfer the address of TM address register 116 to address register 125 for the beam angle. A signal from control logic 114 via cable 130, then initiates the scan line. The video output at line 132 from detector and video amplifier means 129 contains the signals produced by any reflections occuring along this line, and indications of such reflections are shown by intensity modulations of the corresponding scan line produced at the strip chart recorder 44 and upon visual display 34. Control logic 114 then switches duplexer 122 to transfer the address of B address register 118 to address register 125 of the sector scanner system. Again, a signal via cable 130 originating at logic 114, activates block 127 and one line of information appears in the video output line 132, which is then coupled only to the visual display 34.

The address in beam angle address register 125 is also coupled to the CRT display 34 via cable 124 to activate a corresponding radial line 112 in this display, and a timing signal from control logic 114 via cable 130 initiates the writing of this radial line. The B-register 118 address is then incremented by one unit and duplexer 122 is switched back into the TM register and a further scan line is thereafter produced on strip chart recorder 44. On completion of this scan line, duplexer 22 is switched back to the B-l register and a new scan line on the CRT of' display 34 is generated and the B-register again incremented by one unit. This process is continued until the B-register 118 has been incremented through the totality of addresses for the particular sector angle that has been selected. Upon completion of the last scan line of the last address in B register 118, duplexer 122 is returned to the TM register. If the system has been set to effect a TM scan through a selected angle, then the address of TM register 116 is advanced by one increment, and this whole process is reinitiated and repeated through the next CRT frame. After repeating the cycle for the number of frames equal to the totality of lines in the selected angle to be recorded by the TM recorder, the address of the A register 116 will have been incremented through the entire selected angle and correspondingly, a complete TM recording will have been made on the strip chart recorder 44, corresponding to the entire portion of the real-time picture displayed upon CRT display 34 which is included within the selected angle. During the entire process of producing the TM scan, the operator is able to maintain on the visual display 34 the structures within the entire scanned region.

In addition, the radial line that is being recorded on TM recorder 44 is displayed as a brightened radial line on the visual display since this line is displayed at a higher repetition rate than the other lines on the visual display.

The indicator marks 113 of Figure 2 comprise a series of marks spaced at intervals corresponding to one centimeter distances within the human body. These indicator marks provide valuable assistance to the diagnostician in judging the size and spacing of structures being observed in the image 110. These indicator marks are generated in Master Control logic 114 (Figure 1) and are displayed on both the visual display 24 and slave scope 28 during the frame overhead interval between B-scans. They are thus preserved by the photographic record made by camera 32 or video record made by video recorder 40. Since the size of the image may vary depending upon the enlargement of the photographic or video display image, it is important to have suitable calibrations that relate the final image to the actual size of the original structures. Sector size control 156 may also be used to change the size of the displayed image, however master control logic 114 takes this size information into account and provides the appropriate scaling of indicator marks 113.

The fan shaped, two-dimensional, real time, displayed image and thereby the resultant derivative readouts may by means of the apparatus 10 be subjected to a variety of image manipulation procedures, which enable such useful results as varying the resolution of that image, or enable the operator to focus his attention on certain specified portions of that image, or so forth.

Referring to Figure 1, master control logic 114 provides control input signals to drive electronics 30, and to transmitter 16 and receiver 18 associated with transducer 12. An input to master control logic 114 is also provided from a receiver gain control 150 (which is influenced by operator adjustment of depth gain control 152). Depth gain control 152 enables the operator to adjust the receiver gain so as to increase such gain only where the receiver is processing specified portions of the sector scan image 110.

The net result of this arrangement for operator viewing is that such operator can adjust the image 110 so as to intensify lower portions of that image or upper portions, or selected regions of the upper or lower portions thereof. By means of sector gain control 128, the operator can adjust the gain of pre-selected angular regions of the sector scan image 110 so as to highlight the desired structures being imaged. Such angular gain adjustment also enables the operator to compensate for reduced sensitivity of the transducer to detect signals obtained at large scan angles. By proper adjustment of sector gain control 128 a uniform image may be obtained even at very large sector angles.

The master control logic 114 is similarly provided with inputs from reject control 154 and from cata compression control 155.

Reject control 154 acts to establish a threshold level for rejection of signals at receiver 18, thereby to enable noise rejec tion. The compression control 155 varies the receiver gain characteristics so as to enable non-linear processing, i.e., so that the out put from the receiver proceeding toward the display can be rendered proportional to the log of the input, thereby enabling expansion of scale in an area of maximum signal interest. Techniques of this sort are again well-known per se in the signal processing arts.

In addition to the foregoing controls, which are directed at image manipulation, two further controls useful in apparatus 10 are provided. These are a brightness control 157, which essentially functions to increase and decrease the overall image display brightness by applying. in accordance with its setting, an appropriate DC bias to the grid of the CRT in the several displays. A sector size control 156 is provided, which enables the operator at his selection to vary the angle of the sector appearing in the scan.

Thus. in a typical instance, the angle being examined may be varied among such set tings as 20, 40, 60 and 80 degrees. The sector size control 156. acting through mas ter control 114, functions to select a set of radial raster lines 112, the group of lines selected serving to define the sector angle. It should be appreciated in this connection that a relatively high number of such radial lines are utilized to define the sector scan.

As already mentioned, 64 such lines may typically be present when a maximum range of 21 cm has been selected. Regardless of the sector size set when the apparatus 10 is set to its maximum range of 21 cm the total number of such lines will remain the same.

(It is noted that any maximum range may be selected. 21cm. represents a normal max imum to image human organs.) Thus, it will be evident that the total number of available radial lines is considerably greater than the 64 mentioned. In fact, in a typical arrangement, 256 such lines are available to the system; but a total of 64 lines will be selected from the overall possible number of 256, in accordance with the setting on sector size control 156. The group selected defines the particular sector and is sequentially furnished to address register 125 as shown in Figure 3, to enable generation of the sector ! scan. The corollary of the operation just described is, of course, that the definition achieved within the narrower sector scans will be greater than that of the broader scans in that the total number of raster lines remains the same. Accordingly, this enables the operator to achieve increased definition of the image 110 by reducing the angle of the sector scan after initially locating the region of interest to him, whereby greater structural details become evident in the displayed image, as well as in the recordings that may be effected by apparatus 10 in correspondence to the displayed image 110.

As one aspect of the image manipulating features of apparatus 10, a range control 140 is provided, which is connected to master control 114 through line 142. Range control 140 includes adjustable elements enabling the system operator to vary the maximum range or depth of the sector scan so as to adapt the apparatus 10 for use with patients having different physical attributes, for ex ample, the range control may be adjusted to enable viewing at depths up to 21 cm from the transducer or at 7 or 14 cm. The more limited depths are particularly appropriate where the cardiovascular structures of an infant are to be examined. Range control 140, operating through master control 114, controls the transmitter 16, receiver 18 and switching and logic means 15 through con trol cables or lines 144, 146, and 148, and enables such result by varying the trigger pulse rate to the elements of the transducer 12. The range control 140 permits a greater number of radial lines to be used while examining structures at shallower depths. In the examples above 64 lines were typically used for examining structures up to 21 cm deep. By restricting the depth to 14 or 7 cm a total of 96 or 192 lines respectively are used. The greater line density obtained with the restricted depths permits greater struc tural details to become evident in the displayed images.

WHAT WE CLAIM IS: 1. Apparatus, comprising means for transmitting ultrasonic sound into a region of a patient and receiving back ultrasonic sound from said region, said means compris ing transducer means for generating said transmitted ultrasonic sound; first display means adapted for providing from said received ultrasonic sound, a visual display comprising a fan shaped, two-dimensional real-time image of said region, said image comprising a plurality of linear image elements; ECG input means for connection to said patient to provide an ECG signal and means for providing from this ECG signal, an ECG visual display in at least substantially real time; wherein said transducer means comprises a plurality of transducer elements.

2. Apparatus as claimed in claim 1, wherein said plurality of transducer elements is a phased array of said transducer elements.

3. Apparatus as claimed in claim 1 or 2, wherein said means for transmitting and receiving ultrasonic sound is adapted to provide as said transmitted ultrasonic sound, a beam of ultrasonic sound steerable to any desired angle of a fan shaped sector.

4. Apparatus as claimed in any one of claims 1 to 3, wherein said first display means comprises a cathode ray tube for presenting said display.

5. Apparatus as claimed in any one of claims 1 to 4, wherein said first display means is adapted such that said image corresponds to a sector of a cross-sectional plane within said region of said patient, said linear image elements being radially oriented.

6. Apparatus as claimed in any one of claims 1 to 5 wherein said first display means is adapted to brighten at least one said image element.

7. Apparatus as claimed in any one of claims 1 to 6, wherein said first display means comprises selection means for enabling said first display means to indicate selectively at least one portion of said image.

8. Apparatus as claimed in any one of claims 1 to 7, wherein said first display means comprises means for enabling said first display means to provide at intervals in said first display, indicator marks corresponding to predetermined distances in said region of said patient.

9. Apparatus as claimed in any one of claims 1 to 8, wherein said first display means comprises means for enabling said first display means to provide in said fan display, alpha numeric information.

10. Apparatus as claimed in any one of claims 1 to 9, wherein said first display means comprises means for enabling said fan display to comprise time data whereby said image can be analyzed as a function of time.

11. Apparatus as claimed in any one of claims 1 to 10, wherein said first display means is adapted such that said first display means will contain said ECG display.

12. Apparatus as claimed in any one of claims 1 to 11, comprising means for re

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (35)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   radial lines is considerably greater than the 64 mentioned. In fact, in a typical arrangement, 256 such lines are available to the system; but a total of 64 lines will be selected from the overall possible number of 256, in accordance with the setting on sector size control 156. The group selected defines the particular sector and is sequentially furnished to address register 125 as shown in Figure 3, to enable generation of the sector ! scan. The corollary of the operation just described is, of course, that the definition achieved within the narrower sector scans will be greater than that of the broader scans in that the total number of raster lines remains the same. Accordingly, this enables the operator to achieve increased definition of the image 110 by reducing the angle of the sector scan after initially locating the region of interest to him, whereby greater structural details become evident in the displayed image, as well as in the recordings that may be effected by apparatus 10 in correspondence to the displayed image 110.

   As one aspect of the image manipulating features of apparatus 10, a range control 140 is provided, which is connected to master control 114 through line 142. Range control

   140 includes adjustable elements enabling the system operator to vary the maximum range or depth of the sector scan so as to adapt the apparatus 10 for use with patients having different physical attributes, for ex ample, the range control may be adjusted to enable viewing at depths up to 21 cm from the transducer or at 7 or 14 cm. The more limited depths are particularly appropriate where the cardiovascular structures of an infant are to be examined. Range control 140, operating through master control 114, controls the transmitter 16, receiver 18 and switching and logic means 15 through con trol cables or lines 144, 146, and 148, and enables such result by varying the trigger pulse rate to the elements of the transducer 12. The range control 140 permits a greater number of radial lines to be used while examining structures at shallower depths. In the examples above 64 lines were typically used for examining structures up to 21 cm deep. By restricting the depth to 14 or 7 cm a total of 96 or 192 lines respectively are used. The greater line density obtained with the restricted depths permits greater struc tural details to become evident in the displayed images.

   WHAT WE CLAIM IS: 1. Apparatus, comprising means for transmitting ultrasonic sound into a region of a patient and receiving back ultrasonic sound from said region, said means compris ing transducer means for generating said transmitted ultrasonic sound; first display means adapted for providing from said received ultrasonic sound, a visual display comprising a fan shaped, two-dimensional real-time image of said region, said image comprising a plurality of linear image elements; ECG input means for connection to said patient to provide an ECG signal and means for providing from this ECG signal, an ECG visual display in at least substantially real time; wherein said transducer means comprises a plurality of transducer elements.
2. 2. Apparatus as claimed in claim 1, wherein said plurality of transducer elements is a phased array of said transducer elements.
3. 3. Apparatus as claimed in claim 1 or 2, wherein said means for transmitting and receiving ultrasonic sound is adapted to provide as said transmitted ultrasonic sound, a beam of ultrasonic sound steerable to any desired angle of a fan shaped sector.
4. 4. Apparatus as claimed in any one of claims 1 to 3, wherein said first display means comprises a cathode ray tube for presenting said display.
5. 5. Apparatus as claimed in any one of claims 1 to 4, wherein said first display means is adapted such that said image corresponds to a sector of a cross-sectional plane within said region of said patient, said linear image elements being radially oriented.
6. 6. Apparatus as claimed in any one of claims 1 to 5 wherein said first display means is adapted to brighten at least one said image element.
7. 7. Apparatus as claimed in any one of claims 1 to 6, wherein said first display means comprises selection means for enabling said first display means to indicate selectively at least one portion of said image.
8. 8. Apparatus as claimed in any one of claims 1 to 7, wherein said first display means comprises means for enabling said first display means to provide at intervals in said first display, indicator marks corresponding to predetermined distances in said region of said patient.
9. 9. Apparatus as claimed in any one of claims 1 to 8, wherein said first display means comprises means for enabling said first display means to provide in said fan display, alpha numeric information.
10. 10. Apparatus as claimed in any one of claims 1 to 9, wherein said first display means comprises means for enabling said fan display to comprise time data whereby said image can be analyzed as a function of time.
11. 11. Apparatus as claimed in any one of claims 1 to 10, wherein said first display means is adapted such that said first display means will contain said ECG display.
12. 12. Apparatus as claimed in any one of claims 1 to 11, comprising means for re

    freshing at least a portion of said ECG display.
13. 13. Apparatus as claimed in claim 12, wherein said means for refreshing at least a portion of said ECG display is adapted so as to render at least the portion of said ECG display extending from R-wave occurrence to the real time display point resistently visible.
14. 14. Apparatus as claimed in any one of claims 1 to 13 comprising means for providing digitized values of said ECG signal; memory means for storing these digitized values, over at least a portion of said ECG display; means for reading out said stored values from said memory means; and means for converting these read-out values into a signal for generating at least a portion of said ECG display.
15. 15. Apparatus as claimed in any one of claims 1 to 13, comprising means for providing digitized values of said ECG signal; memory means for storing these digitized values as a bit stream; means for reading out said bit stream from said memory means; and means for converting said read-out bit stream into a signal for generating at least a portion of said ECG display.
16. 16. Apparatus as claimed in claim 14 or 15 comprising means for correlating the storage addresses of said stored values and said read-out thereof, with occurrence of R-wave in said ECG signal.
17. 17. Apparatus as claimed in any one of claims 1 to 16. comprising slave display means for operating in synchronism with said first display means and for providing a slave display corresponding to at least a portion of said fan display.
18. 18. Apparatus as claimed in any one of claims 1 to 17 comprising slave display means for operating in synchronism with said first display means and providing a slave display corresponding to at least a portion of said ECG display.
19. 19. Apparatus as claimed in claim 18, comprising control means for sequentially blanking said slave display, for unblanking said slave display for a predetermined period, and then blanking said slave display.
20. 20. Apparatus as claimed in claim 19, comprising means for coordinating said unblanking with a predetermined location on said ECG display to which said slave display corresponds.
21. 21. Apparatus as claimed in any one of claims 1 to 20 comprising means for providing said fan display with a cursor.
22. 22. Apparatus as claimed in claim 21.

    when in accordance with claim 14, wherein said cursor is positionable on said ECG display contained by said fan display.
23. 23. Apparatus as claimed in claim 22, when in accordance with claim 22 or 23, wherein said control means is adapted for effecting said unblanking at a point marked by said cursor on said ECG display.
24. 24. Apparatus as claimed in any one of claims 21 to 23, comprising means for establishing an address for said cursor.
25. 25. Apparatus as claimed in claim 24, when in accordance with claim 4 and claim 12, wherein said means for providing said cursor comprises an operator-actuated up/ down counter; said means for establishing an address for said cursor; display counter means having an output indicative of the position of the beam of said cathode ray tube during said ECG display contained by said first display; and first comparator means for generating a brightening signal for enabling visualization of the spot provided by the beam of said cathode ray tube, upon the counts in said display counter means and said up/down counter indicating that the beam of said cathode ray tube is at a position correlated with a said address for said cursor.
26. 26. Apparatus as claimed in claim 25, when in accordance with any one of claims 19, 20 and 23, wherein said control means comprises means for normally blanking said slave display; detector means responsive to occurrence of R-wave in said ECG signal; acquisition counter means actuatable by this detected R-wave. for establishing addresses at said ECG display; and second comparator means, for providing an output enabling said unblanking upon said acquisition means indicating an address corresponding to a value set in said up/down counter.
27. 27. Apparatus as claimed in any one of claims 1 to 26 comprising means for recording or reproducing said fan display and/or said slave display.
28. 28. Apparatus as claimed in claim 27, wherein there is video recorder means for recording said fan display and/or said slave display.
29. 29. Apparatus as claimed in claim 27 or 28, wherein there is photographic means for photographing said slave display.
30. 30. Apparatus as claimed in claim 29, wherein said photographic means comprises a camera.
31. 31. Apparatus as claimed in claim 29 or 30. wherein said photographic means is svnchronized in relation to said slave display means, this synchronization being adapted to be in accordance with occurrence of a preselected point in a cycle of motion of said region of said patient.
32. 32. Apparatus as claimed in any one of claims 27 to 31. when in accordance with any one of claims 19, 20 and 23, wherein said means for recording or reproducing said fan display and/or said slave display is controlled by said control means, so as enable this recording or reproducing at selected times.
33. 33. Apparatus as claimed in claim 32, when in accordance with claim 11, wherein said control means is adapted to coordinate said unblanking with a predetermined location on said ECG display contained by said fan display.
34. 34. Apparatus as claimed in any one of claims 1 to 33 comprising phonocardiograph input means for providing a phonocardiograph from said patient.
35. 35. Apparatus as claimed in claim 35, wherein said first display means is adapted such that said first display means will contain said phonocardiograph.