Note: Descriptions are shown in the official language in which they were submitted.
"` li;~l7~i~
This application is a division of Canadian applica-
tion 257!216 filed Jlllv 19. 197~
Background of Invention
. .
This invention relates generally to apparatus and
methodology for effecting medical diagnosis, and more
specifically relates to systems and methodology utilizing
ultrasonic techniques for such purposes.
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. As far back as at least 1953,
Edler and Hertz described techniques wherein echoes provided
by structures within the heart, could be converted into curves
indicative of the movements of portions of the said structure.
Techniques of this type have generally been identified under
the term "echocardiography" or by the term "TM" (Time-Motion)
scanning. Pursuant to these teehniques, 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 struetures,
including heart wall, valves, and the like, some of the
energy is reflected baek toward the transducer at the boundaries
between the various struetures. 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
teehniques 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.
'
~ 1
~3~:7S~
Illsofar as the Tt~i sc~n is conccrllecl, it may be obscrved
that up until recently, a ~ajor problem inhercnt in the applicablc
?n~ r~t nc w~c th~t th~ ~nt~r;ll nr w~c; i!~ ~cc~n~; Il fl yin~ hl ~ r~
This is to say tha'~ the only information that such operator
had regarding whether the transducer was properly oriented
for the structures that he ~as 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 whlch 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.
Rec~ntly apparatus has been reported wherein a TM scan
lS 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 be 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.SO Green,
Editor, Plenum Press, 1974. Additional aspects of systems
based upon such apparatus are set forth at Volume 6 of the
sk4G - 3 -
032~76
~` 11~L75~
melltioncd ~cousti_al ilo]o(fraph~ se3-ies at page 91, in an
~rticle by VOIl Ramm, l`~lurston, and Kisslo entltled
- "Cardiovascular Diagnosis l~ith Real Time Ul~rasound Imag-
ing". Reference may also be useully made to J.C. Somer,
"Electronic Sector Scanning for Ultrasonic ~iagnosis",
appearing at page ]53 o~ Ultrasonics for July~ 1968.
The real time imaging systems above mentioned, and
others as have been recently described by additional re-
searchers, have indeed provided use~ul 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 simult-
aneously with the functions occurrence. At the same time,
however, such systems have represented but an initial appr~ j
oach to an extremely complex diagnostic environment; and
the reported systems have been markedly lacking in the
sophistication and flexibility that the diagnostician re- $
quires. Numerous of these prior art systems, for example,
have generated low resolution in the images thereby pro-
vided, and have not included capabilities for manipulating F
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 5
provide, and the various additional diagnostic read-outs
commonly employed by the cardiologist -- including, for
example, ~he well-known ECG, the phonocardiogram, and the
already mentioned TM mode display and recordings.
According to the present invention there is provided
an ultrasonic system of tlle type utilized in pati~nt cardlac
and cardiovascular diagnosis comprising means including a
.
. . .
17S4
multi-element transducer for generating and displaying
a ~an shaped two-dimensional real-time operator-view-
able image on an operator-viewable display means of a
patient region being examined from ult~asonic energy
directed into said patient by said transducer and reflect-
ed out of said region; ECG recording means operatively
associated with said means for generating and displaying
an image, and adapted for connection to said patient
being examined to generate an ECG output from said patient,
said ECG recording means including means for displaying
in real-time said ECG output of said patient ~eing examined
on said operator-viewable means; slave display means
operated in synchronism with said operator-viewable dis-
play means, control means associated with said slave dis-
play to provide a second display thereon of the image on
said operator-viewable display means; and camera means
: positioned for photographing said slave display to enable
photographing of a defined ECG cardiac cycle display the
; real-time display image as controlled by said control
means,
There is described below, a display and recording
system for ultrasonic diagnosis; which system is particularly
applicable to cardiology; and which is capable of directly
displaying for operator investigation a high resolution
and readily manipulatable real time image of cardiac
structures.
The system described belo~ includes means for enabling
simultaneous or independent display of an ECG or a phono-
cardiogram, and in a form ~hich enables the system operator
to readily observe such data.
The diagnositc system, described below, is such that
ultrasonic methodology is used to visualize in a fan shaped
- display in xeal time a cardiac structure or the like,
thereby enabling a . so~called B-mode disp].ay of such
structures, which system further includes means for rapidly
and automatically effecting a TM-mode read-out or scan of
the portion of the cardiac structure then being displayed.
The described system is an ultrasonic imaging system
particularly adapted to the generation of real time B-mode
displays of cardiac structures, which system includes
means for automatically securing photographs of the said
B-mode display; and wherein photographing of said display
may be directly correlated with a timing point referenced
to an ECG being generated by the cardiac structure being
observed, thereby enabling the cardiac structure to be
- 5~ -
i
~ 17~;4 -
- pho~ocJlaphicall~ recorded at thc precise point in tlle
car~ii.c~C l~ Cle ~YlliClL i~ ;leemed of ir;'~er_sJ- ~o thc
diagnostician.
The descri~ed ultrasonic diagnosin~ system, in
addition to including means for o~taining photographs of
the real time B-mode display, includes operator-actuated
means for superimposing alphanumeric and timing info~nation
upon the display, in consequence of which the resultant
photographs are directly provided with precise data
useful for record-keeping or other purposes, including,
e.g., medico-legal or regulatory purposes.
The described ultrasonic diagnosing system, in
addition to including means for producing a video recording
of the real time B-mode display, includes capability for
superimposing precise time information on the displays
being recorded, to thereby facilitate and assure accurate
analysis of the recordings.
The transducer utilized with the sy~tem of the
described embodiment of the invention preferably comprises
.
a phased array consisting of a plurality of elements
arranged in a compact linear array. The transducer is
connected to a suitable transmitter and receiver, and
the transmitted pulses are so phased as to steer the
emitted sound beam in the desired direction. Adjustable
delays provided in each receiver channel enhances the
reception from the same direction as the transmitted sound
beam. By suitably controlling the timing of the voltages
applied
` `" 1~1754
to the transducer elements and the adjustablc delays of
the separate rec~iver chann~ls~ the beam can be steered
to any desired angle of a fan-shaped sector. Operation
of t}~ steered array is such that a plurality of radial
lines defining the fan-shaped sector are successively
generated with a relatively high number of such radial
lines, typically of the order of ~4 such lines, being
utilized in the course of generating the entire 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 system 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 C~T screen.
The use of the phased array sector scanner 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.
It also offers the cardiologist a small light-weight transducer
similar to those used in prior art T~l-mode instruments. In
prior art TM instruments the cardiologist would examine the
various cardiac structures by angulating the transducer to
send the beam successively through the structures of interest
and these are then recorded on a T~l-mode strip chart recorder.
In accordance ~ith this invention, the same type of display is
obtained automatically by permitting the cardiologist to obtain
a TM-r,~ode scan of the two-dimensional picture being observed
on the CRT screen.
Prior art linear-array near-field ultrasonic scanners
sk4G - 7 ~
032476
- '~
54
do not permit ~le same displa~ to be trallslated into a ~
mode scan since they dlsplay ~tle ~-scan picture in a rcct-
angular format rather than the angular format obtained in
the sector scanner. Thus, one of the advantages of the
described embodiment is that it permits a standard ~1-mode
display to be obtained in the usual format as obtained in
the prior art TM-mode recordings with the advantages of
being able to visualize the structures in their actual con-
figurations before and in fact while the TM recording is
made.
Means are provided in the system for varying the sec-
tor siæe of the fan-shaped area ~eing examined by the
transducer,to achieve a desired angular configuration vary-
ing e.g. between 20 and gO degrees. Since the same numberof scan lines are utilized in each instance, such feature
enables increased resolution where a particular portion
of the image is deemed of special interest.
In another aspect of the invention, means are provided
which vary the repetition rate of scan lines as to enable
depth control o~ the displayed sector scan. By this techni-
~ue, examination of less deep portions of the cardiac struc-
ture can be achieved with a corresponding increase in the
line density. For example, when examining structures near
the maximum range of 21 cm in the described device a total
of 64 lines are used. By restricting the maximum depth to
7 cm in said device a total of 192 lines might be used,
providing superior sensitivity while examining infants for
example.
In other aspects of the invention, the data being
processed by the transducer-linked receiver may be varied
to compress portions of same, i.e., to enable non-linear
processing; and the system may include means for rejecting
!
I
signals below a cextain aMp]itude, i.e., to enable noisc
r~ n.
In a further aspect of the control en~led by the
system at the sector-shaped display, means are provided for
varying the gain of the receiver at various sectors of the
examination zone. In this manner, it is possible to com-
pensate for regions of greater attenuation that may occur
in certain regions of the body.
As already mentioned the described system provides for
direct visual display on a CRT accessible for operator
viewing. A slave scope is driven in synchronism with the
visual display and photographic camera means are positioned
to enable photographs to be directly obtained from the slave
scope. The slave scope is also associated with a vidicon,
the outputs of which are provided to both a video recorder
and to a video monitor -- for enabling auxiliary or remote
viewing of the display.
The output from the transducer receiver is also pro-
vided to a TM-mode recorder, which enables TM-mode strip
records to be directly obtained from the present apparatus.
An especially significant aspect of this arrangement is
that the system operator may initiate a TIS recording while
examining the substantially real time display. This feature
! completely obviates the difficulty inherent in the prior
art, wherein the diagnostician was obliged to operate in
partial or entire ignorance of the precise patient area
for which he was preparing the said TM-mode recording.
me TM-mode operation further includes certain capa-
bilities heretofore not provided in such instrument and
especially, of course, not provided in the presence of
the greatly augmented capabilities of the present system.
1~1754
,
l'hus, and in acldit:ion to tl~e capc~ilit~ of effecting a
TM record with respect to t~le time-motion characteristics
- occuring along one or more of selected radial lines of
the scan sector, the present system may be operated in an
automatic mode -- wherein successive TM scanning o each
adjacent radial line is effected, in order to thereby
obtain a TM recording of the entire sector under operator
observation at the system display screen.
The described embodiment further includes ECG input
means, which enable ECG data from the patient to be direct-
ly provided to the said system. The ECG proper is displayed
in real time on the system display screen, and means are
further provided for enabling the generated ECG pattern to
persist for a period sufficient to enable the operator to
identify significant features thereof.
In accordance with a further aspect of the invention,
an operator movable cursor (i.e. an indicia mark) is gener-
ated on the CRT screen, and may be positioned at a desired
point on the ECG record. This operation serves a highly
significant function during preparation o~ photographs.
In particular, means are provided in the system which
enable production of a photograph corresponding to the
real time image at the point in the cardiac cycle identi-
iied by the cursor. This enables the operator to o'otain
a photographic readout at any precise point in the cardiac
cycle which he may deem of pertinence to his examination.
_ g _
17S4
In yet anoth~l .ISpe(`t of ~he sys~em, a ~eyboard input
is associated ~ith suitablc a]phallumeric character g~nerator
mcans, 50 as to cnable insertion of alphanumeeic and other
information upon the visual display. Information may be
thereby entered by the operator respecting 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 is automatically displayed
including data respecting the point of the ECG cycle of
which the photograph is indicative. Informa~ion 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 similarly be superimposed upon
the display screen, as to provide a continual record --
which can extend down to l/lOO's of second, whereby each
full frame (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 deemed of significance,
not only for normal record-keeping purposes, i.e., to enable
ease of correlation of photographs and video recordings with
patient records or so forth; but moreover, the said information
is deemed significant in connection with medico-legal
problems and/or for regulatory purposes, i.e., in order
to conform to such requirements as may be imposed by the
hospital or other institution utilizing the equipment
sk4G - 10 -
032476
,
7:~
or ~y state or fedelal agellcies.
~n e~odiel~lt of thc inventioll will now be described,
-. by way of example, with reference to the dra~ings in which:-
FIGURE 1 is an electrical schematic diagram in block
form and sets forth the key operative el~ments,
FIGURE 2 is a plan view, schematic in nature, of the
display screen portion of the present apparatus;
FIGURE 3 is an electrical schematic block diagram,
illustrating operation of the system in a ~M mode, as well
as indicating certain aspects of the sector generation
- techniques;
FIGURES 4A, 4B and 4C are graphs, setting forth
certain aspec~s of the sequence effected during making of
photographs by the present system; and
FIGURE 5 is an electrical schematic block diagram
illustrating the electronic persistance and exposure
sequencing circuits shown as block 56 in FIGURE 1.
I Description of Preferred Embodiment
.i In FIGURE 1 appended hereto, a display and recording
system 10 is set forth. System 10 operates upon ultrasonic
principles and is intended primarily for use in effecting
` diagnosis of cardiac and cardiovascular conditions, al-
. though it will be evident to those skilled in the present
! art that the said system is useful in other diagnostic
applications in.that the sys~em provides useful informa-
tion in these further environments. However, because of
its primary application to caridac and cardiovascular
diagnostics, the system applied to such an application
will be emphasized in this specification.
-- 1 1 --
13175~
The sonic transd~cer 12 utilized wi~h sys~em 10 is operatively
associated with a patient 14, so ~s to en~ble the u~tra~oni~
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
as to propagate its output between the ribs of the patient.
Although various transducer configurations as are known
to be useful in conjunction with generation of t~o-dimensional
images can be used with the invention including e.g. those
based on so-called "near-field" linear arrays, transducer
12 preferably 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 12mm, a width of 0.3 mm and center-to-center spacing
between adjacent elements of 0.4 mm. Generally the transducer
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 elements utilized is
determined by the operating frequencies, and can typically be
of the order of 0.7 mm where a frequency of 2.5 MHz is utilized.
Transducer 12 is connected through switching and logic
means lS 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, 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 o the separate receiver channels,
sk4G
032~76 - 12
, ~
``; 1~;~175;4
the beam is steexed to desired anc~les o~ a ~an-shaped
sec~or. G~eratioll Ol th~ l`eU array, ~le phclsirlg, and
~he delay sequellces, are e~fected so that a plurality of
radial lines defining the said fan-shaped sector are succ-
essively ~enerated with a relatively high number of such
radial lines, typically in t-he range of 64 to 256, being
utilized in the course of generating the entire sector.
A set of such lines are generated over a short period,
typically of the order of l/30th of a second, whereby the
- correspcnding display - (Figure 2) on the system CRT dis-
play 24 is a high resolution, substantially 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 transla-
ted into brightness variations on the CRT screen.
Further details regarding the signal processing
techniques utilized in conne¢tion with transducer 12 to
generate the mentioned fan-shaped sector 25 (Fig.2) J are
set ~orth in U.S. Patent No. 4,005,382 (issued January
25, 1977), entitled "SIGNAL PROCESSOR FOR ULTRASONIC
IMAGING", and assigned to the assignee of the present
application.
i The output from receiver 18 proceeding Yia line 20l
is provided in parallel to three instrumentalities. First-
ly, such output is provided.via line 22 to a visual dis-
play 24, which as mentioned typically takes the form of a
conventional CRT screen directly viewable by the system
operator. It may however, comprise other display devices
such as for example a plasma display panel. Via line 26,
the said output is also 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
- 13 -
``' 1~;~17~
voltages of cach o the CRrl~s. In consequence of this
arrangelllellt, ihe ~Le~i~ie ui~;play belng provided at ani
~iven time for operator viewing at display 24, is also
simultaneously present at slave scope 28.
Operatively associated with slave scope 28 is a
repxoductive means which may comprise a photographic
camera 32 mounted in spaced relationship from the CRT
screen of the salve scope as to enable direct photographing
of such screen at selected times. An output image is
also ta~en at 34 from slave scope 2S and provided to a
conventional vidicon 36. m e vidicon 36, in turn, provides
an oùtput 38 to a video recorder 40. A video monitor 42
may also 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.
In accordance with a key aspect of the embodiment 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 examina-
tion 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~ m e TM recorder 44 used in the
present system is of this same type; and while the manner
in which it interacts with the remaining elements of the
I system 10 produce new and highly unexpected results
¦ (as will be hereinbelow discussed~, the recorder
- 14 -
I
1754
per se may be of a conventional design. Thus, 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.
Nextly, there is seen to be associated with system 10
an ECG sensing and recording means.In particular, an ECG
sensor 50 is provided, which may constitute the usual elec-
trodes and related paraphernalia operatively associatable
with the patient being examined.The output from sensor 50 is
provided to an ECG amplifier 52. In accordance with this
aspect of the invention, the output 54 of 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 there-
fore, 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 devel-
oping trace for at least a portion of the ECG cycle suffici-
ent 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 Fig. 5
and is described more fully below.Essentially the persistence
function to refresh a portion of the ECG trace for a desired
period. In a typical instance, for example, and referring to
FIGURE 2 the point 103 may be assumed to represent the devel-
oping 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 of block 56~ so that this portion
-15-
~1~17~i4
of thc devcloping trace xemains visible or ex~mli3latio~
by ~le opera~or.
In accordance with an additioIlal aspect, it may
also be found useful to provide, in addition to the ECG
input, a phonocardiograph capability or other physiologi-
cal detectin~ and recording devices. ~hus, a microphone
60 is provided, the input of which is connected to
phonocardiograph 61 and thence via auxiliary ampli~ier
62 to the same electronic persistance circuits of block
- 56 as are used for the ECG system, so that the phonocardio-
graph output can, if desired, be placed upon visual dis-
play 24 and recorded, photographed or so forth, by the
vari.ous recording elements of the system. In similar
fashion, other physiological inputs as indicated by aux-
iliary physiological input block 63 may be amplified by
amplifier 62 and provided to circuits of block 56. Thus
for example, the auxiliary input 63 may comprise a res-
piration monitor.
An operator~actuated keyboard input 64 is provided
in the present system, which enables insertion onto the
various displays of identification data and of additional
important information. In particular, the keyboard actu-
ates an alphanumeric character generator 66 and/or a clock
68, which provide time data and various alphanumeric identi-
fication data through the lines 70 and 20 to the visual
display 24 and slave scope 28. By referring to FIGURE 2,
it may thus be seen that certain information of the type
just discussed may be inserted by the operator upon the
display. For example, patient identification data by
number, name, or so forth, appears at 104 and operator
identification appears at 105, the da~e of examination at
i 106, and time information at 107, and camera sequence
information at 109. The data at 111
- 16 -
7 5~
compri-;es the elclpsed tin)e from the ~-wave pea~ of the
ECG to the time the camera effec~s a picture of the B~scan
data as explainecl more ~ully below.
The types of information indicated serve several
important purposes. In the simplest instance, the identification
data, as it will appear on photographs and video recordings
obtained by the present system, enables direct identification
of the records to the patier.t, 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, as it
is normally provided in lOOths of a second, uniquely identifies
each frame on the CRT (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.
2Q 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 camera means 32 associated with the present system
may be of any conventional construction. Various models
of the well-known "Polaroid" cameras as well as display
type xerographic cameras, as for example commercially a~ailable
sk4H
032576 - 17 ~
1.
` 11;~17S4
irom V~rian ~ssociates are well suited for the present
pur~s~s. In a~ol-dal~e witll tllc techl-iques utilized in
the present system 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. l`he 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 electronie
persistance and exposure sequence eircuits 56. The latter
in particular, aeting through cursor positioning switch
95, moves a cursor mark to any preseleeted region of the ---
ECG display 101, sueh eursor indication being for example
a brightening of tne ECG display at the desired point.
Sueh a point is indieated in ~iy. 2 by point 108.
The timing of the eamera sequence is explained with
the aid of Figs. 4A through 4C. When a photograph is desired,
eamera logic 80 is aetivated by the operator initiating
the photo sequencer 85. After aetivation, indieated at time
83 on the ECG 100 of Fig. 4A, eamera lo~ic 80 immediately
blanks the screen of the slave scope by receiving the
unblanking signal on line 81 from Master Control logie 114
and preventing it from being applied via cables 78 and 79
to slave scope 28. The blanked and u~nblanked condition of
slave scope 28 is depicted in Fig. 4B. The eamera logie
80 through camera actuate 82 opens the shutter of camera
32 as depicted in Fig~ 4C. The system then continues to
operate with the slave scope screen blanked until the next
R-wave (Fig. 4~) is detected by eleetronic persistant and
exposure sequence circuits 56. When the horizontal
position of the ECG arrives at the cursor marker 108 at time
sk4H
0325~6 - 18 -
1~ 754
89, a tri.ggcr signal is sent from circuits 5G to slavc
SGOpe 28, to unblallk the B-scan to provi.de one frame of
cardiac data on slave scope 28. This unblankill~ period
lasts about 20 milliseconds which is adequate to display
and record one frame of ~-scan data.
The slave scope 28 is then again blanked (at 93 in Fig.
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. The system is then blanked again
(at 99) and the camera shutter closes, after ~hich the display
is again unblanked and normal operations are continued.
The camera film is then advanced and the system is ready
for the picture or for continued normal operations.
It will be further noted that a multiple exposure set
means 98 is provided which can be set by the operator as
to enable repeated exposures on the same photographic frame
of the selected portion of the cardiac cycle. This may be
. desired in particular instances in order to obtain sufficient
exposure or contrast in the photographic film or plate.
Fig. 5 is a block diagram of the electronic persistence
and exposure sequence circuits 56 of Fig. 1. These circuits
enable a persistant ECG signal to be displayed on the main
display and slave scope 28 and provides signals with the
aid of camera logic 80 to enable a photograph to be obtained
at a predetermined point in the cardi.ac cycle.
ECG signals from the ECG amplifier 52 and phonocardiogram
signals from amplifier 62 are coupled via lines 54 and 55
respectively to the amplifier 552 for amplifications to
a level suitable for digitization, typically in the voltage
range of 100 to 1000 millivolts. These signals are then digitized
sk5I
~3~576 - 19 -
7~4
by the analog-to-digital converter 554 and fed into the
random access memory 556. The address of memory 556 is det-
ermined either by the display counter 558 or by acquisition
counter 560. 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 acqui-
sition 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 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 approximately 200 Hz as the input
frequency to counter 560. Counter 560 will continue to ad-
vance as it receives pulses from divider 566 until the coun-
ter 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 de-
tector 574 applies a voltage on line 576 to AND gate 578.
If 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 f~om peak detector
574 activates AND gate 578 to produce a positive output on
582 which is applied to reset input of 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
-20-
76-17
75~
~ddress a~ tl~e peak o~ t~e R-wave, and subseqllellt memory
locations are used to store the digital ECG ~iqnal as it
i~ ~L~en~ed co memory 556 by ~DC 554. rrypically memory
556 may contain 512 memory locations so that approximately
`S 2 full seconds o~ ECG information ~ould 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 describéd.
The visual display 24 and slave scope 28 of Fig. 1 are capable
of writing only one piece of data 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
and slave scopes. 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 ~ I
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 Fig. 1 to
the persistence and exposure sequencing circuits Fig. 5
~ia control line 77. This 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
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1~1754
to the drive electronics 30 of Fig. 1 to provide the Y axis
deflection signal for the display and slave scopes. The
frame overhead signal on 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 mem-
ory 556.As clock 564 is advancing counter 558 at approximate-
ly a 50kHz rate, all 512 addresses in memory 556 will be read
out in approximatelya 10-millisecond period. The digital-to-
analog converter 590 also receives the address from display
counter 558 and converts it to an analog signal on line 592 that
is coupled to drive electronics 30 of Fig. 1 to drive the
X axis of the visual display and slave scope.
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 when the
count of display counter 558 is less than the count at acqui-
sition counter 560. The unblanking signal is derived by
applying the output signal on line 596 of digital comparator
594 with the fram 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 Fig. 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 unblanking signal which appears
on line 599 ensures that only that part of the ECG will app-
ear on the display screen that corresponds to the ECG in the
current cardiac cycle and the point at th~ 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 visi-
ble on the screen is the~by very
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11;~17S4 ' I
short alld as time progresses this trace ~ccomcs lonqer and ,l
~ V ~ ~ ~J ~ t h,~ ~ n ~ l r ~ c f~ r F~ t~ n
The mechanism to provide a cursor indicator upon the
displayed ECG signal and its use in controlling the camera
sequence wil] now be considered. The use of the cursor
positioning switch 95 has been indicated above in the t
description of Fig. 1. Up-down 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
9S. By grounding terminal 616, by means of switch 614 the
eounter will advance whereas grounding terminal 618 will
eause the eounter to advance in the reverse directon as
it is driven by clock 620. ~hen the switch 95 remains in
its center position the contents of up-down counter 612
will remain unchanged even though it is eoupled to clock
620. The contents of counter up-down 612 is compared
with the contents of display counter 558 by comparator 622.
j When the count in counters 612 and 558 are equal comparator
622 ~rill put a signal on line 624 which is coupled to visual
display 24 and slave scope 28 through cable 58 (Fig. 1).
The ECG signals of both the visual display and slave scope
ar briqhtened, the displayed ECG signals for that one address
thereby providing a eursor indication of that point in the
eardiac cyele. By means of switch 95 the operator can place
the eursor marker at any desired point in the eardiac cycle.
One of the main purposes of the eursor marker just
. .
described is to select and indicate the pre-selected point in
the cardiae cycle at which the operator desires a photograph
of the B-mode scan. The general sequence for camera operation
is already described above. The operator, by switch means
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3257~
- 23 ~
'...... ~ '~
: . :'. ':" .
..
. : ' ' :
~w ~1~17~4
95, placec; ti~e cursor rn~rk at the point in the cardiac cycle
at whioh a photogra~h of the B-scan is desired. The photo
sequence initiator 85 (Fig. 1), when activated by the operator,
causes camera lo~ic 80 to blank the screen of the slave
S scope by removal of the photo B-scan unblank signal on line
630 (Fig. 5) and opens the camera shutter as depicted in
Figs. 4B and C respectively. The time at which the screen
is unblanked is selected to be the time at which the ECG
signal arrives at point 108 of Fig. 4A. Referring now again
to Fig. 5, this time occurs when the count of acquisition
counter 56Q is equal to the count in up-down counter 612.
These two counts are compared by comparator 623 so that
when these two counts are identical an output occurs on
line 625. The signal on line 625 then unblanks the display
lS 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 unblanking
signal on 630 which was derived in camera logic 80 of Fig.
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 (Fig. 1~ to slave scope 28.
The circuits of Fig. 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
sk4H
032576 ~ 24
,,--.
s ~
7 5 ~- -
siynal to appear on tl)o final film. Once this has
~een accomplished, the shutter can be closed and the frame
~"1~ r ~
System lO, when utilizcd for providing a TM recording
may be utilized in one of two modes, each of which uniquely
interact with the other elements of the present system.
In partic~lar, a unique advantage derived from the
` present system arise by virtue of the fact that the operator
thereof is able to visually 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
; 15 TM recording in the accepted format or were basically
; deficient in requiring the diagnostician to effect a TM
recording witho~t 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.
In the present device the operator is able to select specific
planes of interect 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 instrument
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 the present system is that the particular section Being
recorded on the TM recorder may be identified o~ B-scan
display by an increase in brightness of the corresponding
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032576 - 25 -
754
part of the image.
Re~erring to EIGURE 3 (and also cross-rcferencing
Flg. ~)~ a scnematic Diock diagralll a~Ijea~ t~ y f~
details of the TM recording modes of operation. The CRT
screen image is generally indicated at 110, such image
peing provided at visual display 34. As image 110 is in
real time, the diagnostlcian can readily angulate or position
transducer 12 to obtain the desired structures within
the two-dimensional image. The image, as already discussed,
is comprised of a series of radial lines 112, each line
- representing a preselected direction of the ultrasonic
beam and the receiver steering pattern.
The schematic arrangement of FIG~RE 3 provides
a switching'and control subsystem which will select one or
a series of predetermined 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
~ig. 1, master control logic 114 provides inputs to address
the TM register 116 (Fig. 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. Logic 114 also
provides control through line 120 to duplexer 122 and
electronic switch 126 so that when TM address register 116
is coupled to beam anqle address register 125, electronic
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032576 ~ ~6
75~
sw;tch 126 co-1ples he video output on line 132 to ~
;ecordc. .~4. ~hcr. ~ ..ddr^s register 1'8 is coupled to
the beam angle address register 125, the video output
line 132 is coupled only to visual display 34.
In operation of system 10 for generation of the B-mode
image 110, duplexer 122 maintains the coupling of B address
register to the beam angle address register and the video
; output is coupled only to visual display 34. In this mode,
cohtrol logic 114 increments the address contained in
register 118 by one number for each radial line 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 transmitter/receiver, and switching logic block 127, are
controlled by beam angle address register 125 (corresponding
to elements 15, 16 and 18 in Fig. 1), and then by detector
and video amplifier means 129, to enable the said visual
display.
When the diagnostician is ready for the said TM scan,
he activates T.M. activator means 115 (Fig. 1) for controlling
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 o~ a single
TM-line sought to be examined may be set into register
116; or logic 114 may be set to effect TM recording of
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--.. . . .
` \
7S4
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 add-
ress 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 re-
corder 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 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 logic 114
~ via cable 130 initiates the writing of this radial line. TheB-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-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 total-
ity of addresses for the particular sector angle that
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754
has beell selected.
Upo~. completion of the last s~n line of the last address
in l3 register ll8, duplexer 122 is returned to the TM register.
If the system has been set to effect a TM scan through a
s 5 selected ansle, then the address of TM register 11~ 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 ~he totality of
lines in the selected angle to be recorded by the T~l 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.
It might be pointed out here that the indicator marks 113
of Fig. 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 (Fig. 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
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.,. __. ., . _ . . .
17~4
proserved b~ the pho~ographic record made by calnera 32
or video record made by video recorder 40. Since tlle size
o~ t~le image may vary depelldillg upoll tne eniargeme~ f
the photographic or video dosplay 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
lG scaling of indicator marks 113.
As a further aspect of the present invention, the
real time two-dimensional displayed image and thereby the
resultant derivative readouts may, by means of the present
system, be subjected to a variety of image manipulation
procedures, which enable such useful results as varying
the resolution of the image, or enabling the operator to
focus his attention on certain specified portions of the
image, or so forth. Continuing, therefore, to refer to
FIG~RE 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 114 is also provided from
a receiver gain control 150 which, in turn, is influenced
by operator adjustment of depth gain control 152. Depth
yain 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 system so
as to intensify lower portions of the image or upper portions,
or selected regions of the upper or lower portions.
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1754
~3y means of s~ctor gaill control 128, the operator ca
a~so adjust the system so as to adjust the gain of
pre-selected an~ular regions of the sector so as to
highlight the desired structures beinq 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 data compression
control 15S. Re~ect control 154 acts to establish a threshold
level for rejection of signals at receiver 18, i.e., to
thereby enable noise rejection, as is known in the art of
receiver operation. The compression control 155 varies the
receiver gain characteristics so as to enable non--linear
processing, i.e., so that the output 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
; 25 system 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 C~T in the several displays and, in addition, a sector
size control 156 is provided, which enables the operator
at his selection to vary the angle of the sector appearing
.
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...
17S4
~n the SCall. Th~s, in a typical ins~nce, the anglc being
exarnil-ed may bc varied amollg such settings as 20 , ~0
~n ; ?n~ ~n (l~gr~es. In accordance with this aspect of the
invention, the sector size control 156, acting through master
control 114, functions to select a set of radial raster
lines 112, the group of lines selected serving to define
the sector angle set. It should be appreciated in this
connection that a relatively high number of such radial
lines are utilized to define the sector scan in the present
system. 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 within the system, when
the system 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 maximum 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 such lines
will be selected from the overall possible number of 256,
in accordance with the setting on sector si~e control
156. The group selected defines the particular sector
and is sequentially furnished to address register 125 as shown
in FIG. 3, to enable generation of the sector scan. The
correllary 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 feature of the invention enables the operator to achieve
increased definition of the image by reducing the angle of
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17~;4
thc scctor scan a~tcr initially loca~ing ~h~ r~gion of
interest to him, whereby gr~ater structural details become
eviaen~ in ~ne aispiayeu image, as well as in tne recoraings
that ma~ be e~ected by system 10 in correspondence to the
displayed image.
As one aspect of the image manipulating features of
- system 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 system for use with patients having different physical
attributes, for example, 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, which, as indicated, controls the
transmitter 16, receiver 18 and switching and logic means 15
through control cables 144, 146, and 148, enables such
result by varying the trigger pulse rate to the elements
of the transducer.
The range control permits a greater rumber
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 structural
details to become evident in the displayed images
While the present invention has been particularly
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31754`-- --- ;
set ~or~h in terms oE speci~ic embodilllellts thereoE, it will
nd e r s t c~ . i n ~ o th~ r l~ P CP n t t P ~ ; n~l t h~ t n llm ~ r ~ c
variations upon tne invention are now enabled to those skilled
in the art, which variations yet reside within the scope of
the present teaching. Accordingly, the invention is to be
broadly construed and limited only by the scope and spirit
of the claims now appended hereto.
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