U.S. patent application number 10/445178 was filed with the patent office on 2003-11-27 for miniaturized ultrasound apparatus and method.
Invention is credited to Brennan, James M., Imran, Mir A., Lipps, William D., McLaughlin, Glen W..
Application Number | 20030220573 10/445178 |
Document ID | / |
Family ID | 23492059 |
Filed Date | 2003-11-27 |
United States Patent
Application |
20030220573 |
Kind Code |
A1 |
Imran, Mir A. ; et
al. |
November 27, 2003 |
Miniaturized ultrasound apparatus and method
Abstract
Ultrasound apparatus for examining tissue in a region of
interest in a body comprising a housing having a viewing aperture.
An ultrasonic transducer is provided comprised of an array of
ultrasonic elements disposed in the viewing aperture. Electrical
pulses are supplied to the transducer for transducer excitation to
introduce ultrasonic signals into the body for reflection from the
tissue in the region of interest. The transducer is capable of
converting ultrasonic signals reflected from the tissue within the
body to the transducer to provide electrical signals. The
electrical signals are gain corrected in accordance with time.
In-phase and out-of-phase components of the electrical signals are
provided and then digitized. The digitized electrical signals are
collected to form one image for a single frame of the tissue in the
region of interest in the body from transducer excitations less
than thirty-three in number which is then displayed.
Inventors: |
Imran, Mir A.; (Los Altos
Hills, CA) ; McLaughlin, Glen W.; (Saratoga, CA)
; Lipps, William D.; (Rocklin, CA) ; Brennan,
James M.; (San Jose, CA) |
Correspondence
Address: |
DORSEY & WHITNEY LLP
INTELLECTUAL PROPERTY DEPARTMENT
4 EMBARCADERO CENTER
SUITE 3400
SAN FRANCISCO
CA
94111
US
|
Family ID: |
23492059 |
Appl. No.: |
10/445178 |
Filed: |
May 23, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10445178 |
May 23, 2003 |
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09860209 |
May 18, 2001 |
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6569102 |
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09860209 |
May 18, 2001 |
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09378175 |
Aug 20, 1999 |
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6251073 |
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Current U.S.
Class: |
600/459 |
Current CPC
Class: |
A61B 8/465 20130101;
G01S 7/52034 20130101; A61B 8/13 20130101; A61B 8/467 20130101;
A61B 8/56 20130101; A61B 8/4438 20130101; A61B 8/08 20130101; A61B
8/469 20130101; A61B 8/488 20130101; G01S 7/52082 20130101; A61B
8/06 20130101; G01S 7/52096 20130101; A61B 8/0866 20130101; G01S
15/8979 20130101; A61B 8/4455 20130101; A61B 8/0833 20130101; G01S
7/52084 20130101; A61B 8/462 20130101; A61B 8/4427 20130101; G01S
15/8981 20130101; G01S 7/52079 20130101; A61B 8/4209 20130101; G01S
7/5208 20130101 |
Class at
Publication: |
600/459 |
International
Class: |
A61B 008/14 |
Claims
What is claimed:
1. Ultrasound apparatus for examining tissue in a region of
interest in a body comprising a housing having a viewing aperture,
an ultrasonic transducer comprised of an array of ultrasonic
elements disposed in the viewing aperture and having an inherent
resolution, means substantially transparent to ultrasound carried
by the housing forming an impedance matching lens overlying the
array and having a surface capable of being placed in contact with
the body, means for supplying transmitted electrical pulses to said
at least one transducer for single transducer excitation but less
than six to introduce ultrasonic signals into the body for
reflection from the tissue in the region of interest, said
transducer being capable of converting ultrasonic signals reflected
from within the body to provide electrical signals, means providing
gain correction of the electrical signals in accordance with time,
mixing means for providing in-phase and out-of-phase components of
the gain corrected electrical signals, means for digitizing the
in-phase and out-of-phase components of the electrical signals,
means for collecting the digitized electrical signals to form one
image for a single frame of the tissue in the region of interest in
the body from transducer excitations less than thirty-three in
number, memory means for storing the digitized electrical signals
of the single frame by storing the magnitude, phase angle and time
of receipt of each received digitized electrical signal to provide
preprocessed data, display means to utilize the preprocessed data
and means coupling the memory means to the display means to provide
a visual image of the tissue in the region of interest in the
body.
2. Apparatus as in claim 1 further including means for increasing
the visual resolution of the visual image to the inherent
resolution of the transducer.
3. Apparatus as in claim 1 for use with a remote display unit and
further including means for exporting the preprocessed data to the
remote display unit.
4. Apparatus as in claim 1 further including means for averaging
the digitized electrical signals for a plurality of frames prior to
collection of the digitized electrical signals for image
construction to improve the resolution of the visual image.
5. Apparatus as in claim 1 wherein said array is a linear
array.
6. Apparatus as in claim 1 wherein said array is a phased
array.
7. Apparatus as in claim 1 wherein said array is a curved array
8. Apparatus as in claim 1 wherein said display is disposed in a
separate display module separate from the housing.
9. Apparatus as in claim 1 wherein said display module is a cathode
ray tube.
10. Apparatus as in claim 1 wherein said display is a liquid
crystal display.
11. Apparatus as in claim 1 wherein said housing is formed in first
and second parts, said second part being detachable from the first
part, said second part having the viewing aperture therein, an
array of ultrasonic transducers disposed in the viewing aperture
and an impedance matching lens overlying the array of ultrasonic
transducers.
12. Apparatus as in claim 11 wherein a plurality of second parts
are provided with each of the second parts having a different
frequency range suited for a specific imaging objective.
13. Apparatus as in claim 12 further including cooperative means
including a non-volatile memory carried by the second part for
informing the first part of the frequency range of the second part
so that viewing can take place of the region of interest.
14. Apparatus as in claim 1 wherein said display is integrated into
said housing.
15. Apparatus as in claim 1 further comprising a separate display
module and wherein said display means is disposed in the display
module and electrical circuit means interconnecting the housing
with the display module.
16. Apparatus as in claim 1 wherein electrical circuit means
includes an interconnecting cable.
17. Apparatus as in claim 11 wherein said housing also includes a
main module and wherein said main module and display module are
formed into a mating clam-shell-like construction.
18. Apparatus as in claim 1 for use with a probe and further
including a support platform adapted to be placed on the surface of
the body and being formed to receive the housing for positioning
the housing for movement with respect to the support structure and
the body and a carriage formed to receive the probe and slidably
mounted on the support platform.
19. Apparatus as in claim 18 further including a scale on the
support platform for ascertaining movement of the carriage on the
support platform and a scale carried by the display corresponding
to the scale on the support platform whereby the relative
positioning between the probe and the region of interest in the
body can be ascertained by viewing the display means.
20. Apparatus as in claim 1 wherein said housing includes means for
receiving a removable memory card.
21. Apparatus as in claim 1 wherein said memory card is an industry
standard modem card.
22. Apparatus as in claim 1 further including means for recording
multiple images of the region of interest at spaced apart
locations.
23. Apparatus as in claim 1 wherein said location are sequential
and are equally spaced apart.
24. Apparatus as in claim 21 further including means for displaying
said multiple images on the display means to create a kinetic image
of the region of interest.
25. Apparatus as in claim 22 wherein said means for recording
multiple images at spaced apart locations includes support means
for supporting the housing and being adapted to be seated on the
surface of the body, said support means including means permitting
the movement of the housing relative to the support means whereby
different views can be taken of the region of interest.
26. Apparatus as in claim 25 wherein said means permitting movement
of the housing relative to the support means permits pivotal
movement.
27. Apparatus as in claim 25 wherein said means for supporting the
housing and permitting movement of the housing relative to the
support means is constructed to permit linear movement.
28. Apparatus as in claim 25 further including means actuated by
movement of the housing relative to the support means to cause the
taking of sequential images as the movement is occurring.
29. Apparatus as in claim 28 wherein said means includes a trigger
mechanism.
30. Apparatus as in claim 29 wherein said trigger mechanism is an
optical reader.
31. Apparatus in claim 1 wherein the means for collecting the
digitized electrical signals includes means for selecting a wave
packet of electrical signals in space having a center, means for
selecting a point (x,y) in the wave packet, means for calculating
the distance from the center of the wave packet around the point
(x,y) to a selected element of the array of the transducer, means
for converting distance to time to select the sample points, means
for interpolating the phase and magnitude between the nearest
sample points and the point to be calculated to determine the
corrected phase and magnitude of the point being calculated, means
for repeating the same sequence of steps for each of the ultrasonic
elements of the array of the transducer and means for summing the
calculated points of corrected phase and magnitude.
32. Apparatus as in claim 31 further including means for
incrementing (x,y) to obtain the center of the next wave packet to
be utilized for calculating additional points of the image.
33. A method for examining tissue in a region of interest in a body
by the use of an ultrasound transducer comprised of an array of
ultrasonic elements in which the transducer is excited by received
ultrasonic signals to provide electrical signals, the method
comprising the steps of receiving the electrical signals from the
transducer and providing in-phase and out-of-phase components of
the electrical signals, digitizing the electrical signals,
collecting the digitized electrical signals at one time to form one
image for a single frame of the tissue in the region of interest in
the body from transducer excitations less than thirty-three in
number, storing the collected electrical digitized signals of the
single frame by storing the magnitude, phase angle and time of
receipt of each electrical signal and displaying the stored
electrical digitized signals of the single frame as a visual image
of the tissue in the region of interest in the body.
34. A method as in claim 31 which includes the use of electronics
and a microprocessor for controlling the electronics, further
including the step of using the microprocessor for placing at least
certain parts of the electronics in a sleep mode when those parts
have performed their functions to conserve power.
35. A method as in claim 33 further including the step of averaging
the digitized electrical signals for a plurality of frames prior to
collection of the digitized electrical signals for image
construction to improve the resolution of the visual image.
36. A method as in claim 31 wherein the step of collecting the
digitized electrical signals includes the steps of selecting a wave
packet of electrical signals in space having a center, selecting a
point (x,y) in the wave packet, calculating the distance from the
center of the wave packet around the point (x,y) to a selected
element of the array of the transducer, interpolating the phase and
magnitude between the nearest adjacent points in the wave packet to
determine the corrected phase and magnitude of the point being
calculated, repeating the same steps for each of the ultrasonic
elements of the array of the transducer and summing the calculated
points of corrected phase and magnitude to provide an image.
37. A method as in claim 36 further including incrementing x (x,y)
to obtain the center of the next wave packet to be utilized for
calculating additional points of the image.
Description
[0001] This invention relates to a miniaturized ultrasound
apparatus and method.
[0002] Ultrasound measuring apparatus of various types is in use at
the present time for industrial and medical applications and
particularly in medical diagnostic applications. Such apparatus,
however, is often of a large size and is relatively expensive. In
addition it is relatively complicated to use. There is a dramatic
need for such apparatus which can be made more compact and less
expensive and have greater simplicity in operation.
[0003] In general, it is an object of the present invention to
provide a miniaturized ultrasound apparatus and method by which the
apparatus can be greatly reduced in size and in cost.
[0004] Another object of the invention is to provide an apparatus
of the above character which is portable.
[0005] Another object of the invention is to provide an apparatus
of the above character which can be packaged in a pocket-sized
hand-held device.
[0006] Another object of the invention is to provide an apparatus
and method of the above character in which power management is used
to make possible low power requirements.
[0007] Another object of the invention is to provide an apparatus
and method in which detachable scan heads are utilized for
selecting desired frequencies for the specific application
envisioned.
[0008] Another object of the invention is to provide an apparatus
and method of the above character in which a particularly novel
imaging approach has been utilized to collect all the data at one
time utilized for making an image in one frame from transducer
excitations less than thirty-three in number to thereby reduce
required the electronics and to greatly reduce power
consumption.
[0009] Another object of the invention is to provide an apparatus
and method of the above character in which it is possible to create
a single frame per excitation of the ultrasonic transducer.
[0010] Another object of the invention is to provide an apparatus
and method of the above character in which a constant pixel density
is obtained.
[0011] Another object of the invention is to provide an apparatus
and method of the above character in which averaging of
preprocessed data can be achieved prior to image construction to
provide signal-to-noise enhancement.
[0012] Another object of the invention is to provide an apparatus
and method of the above character which has an extremely low duty
cycle.
[0013] Another object of the invention is to provide an apparatus
and method of the above character which can be utilized with
linear, curved and phased arrays.
[0014] Another object of the invention is to provide an apparatus
and method of the above character in which a zoom feature is
provided to make possible enlargement up to the inherent resolution
of the transducer array.
[0015] Another object of the invention is to provide an apparatus
and method of the above character in which a non-volatile memory
device is utilized in the scan head so that the associated
electronics can be advised of the frequency range of the scan
head.
[0016] Another object of the invention is to provide an apparatus
and method of the above character which is particularly useful in
directing probes such as needles to a desired site.
[0017] Another object of the invention is to provide an apparatus
and method of the above character in which multiple images are
provided of spaced-apart locations in the region of interest in the
body.
[0018] Another object of the invention is to provide an apparatus
and method of the above character in which the multiple images are
spaced apart at desired intervals.
[0019] Another object of the invention is to provide an apparatus
and method of the above character in which the multiple images are
angularly spaced apart.
[0020] Another object of the invention is to provide an apparatus
and method of the above character in which the images of the
spaced-apart locations are spaced apart at proportionate
intervals.
[0021] Another object of the invention is to provide an apparatus
and method of the above character in which the spaced-apart images
are sequentially displayed to create a kinetic image of the region
of interest in the body.
[0022] Another object of the invention is to provide an apparatus
and method of the above character in which the multiple images are
obtained by movement of the transducer array with respect to the
body.
[0023] Another object of the invention is to provide an apparatus
and method of the above character which is applicable to a variety
of medical diagnostic procedures.
[0024] Additional objects and features of the invention will appear
from the following description in which the preferred embodiments
are set forth in detail in conjunction with the accompanying
drawings.
[0025] FIG. 1 is an isometric view of a miniaturized ultrasound
apparatus incorporating the present invention with a detachable
scan head with certain portions broken away.
[0026] FIG. 2 is an isometric view of the detachable scan head
forming a part of the apparatus shown in FIG. 1 and which utilizes
an ultrasonic transducer having an array.
[0027] FIG. 3 is an isometric view of an alternative detachable
scan head for use with the apparatus shown in FIG. 1 which has a
transducer incorporating a phased array.
[0028] FIG. 4 is a block diagram of the electronics utilized in the
apparatus shown in FIG. 1.
[0029] FIG. 5 is a flow chart showing the steps used for ultrasound
image construction in the present apparatus and method.
[0030] FIG. 6 is an isometric view of another embodiment of the
ultrasonic apparatus incorporating the present invention utilized
for guiding a needle or probe.
[0031] FIG. 7 is an isometric view of an ultrasonic apparatus
incorporating the present invention in which a main or base module
and a display module are provided.
[0032] FIG. 8 is an isometric view showing the main or base module
and the display module shown in FIG. 7 coupled together in a
clam-shell-like manner.
[0033] FIG. 9 is an isometric view of another embodiment of the
ultrasound apparatus of the present invention which incorporates
the use of linear spatial imaging.
[0034] FIG. 10 is an isometric view of an ultrasonic apparatus
incorporating the present invention for obtaining kinetic imaging
utilizing sector scanning.
[0035] FIG. 11 is an isometric view of another embodiment of an
ultrasonic apparatus incorporating the present invention
incorporating a probe.
[0036] In general, the ultrasound apparatus of the present
invention is for examining a region of interest in a body and
comprises a housing having a viewing aperture. An array of
transducers is disposed in the viewing aperture. Means
substantially transparent to ultrasound is carried by the housing
and forms an impedance matching lens overlying the transducer array
and has a surface capable of being placed in contact with the body.
The array of ultrasonic transducers is capable of converting
ultrasonic energy reflected from within the body to the array of
transducers to provide electrical signals. Means is provided for
providing gain correction of the electrical signals in accordance
with time. Mixing means is provided for providing in-phase and
out-of-phase components of the electrical signals. Means is
provided for digitizing the in- and out-of-phase components of the
electrical signals. Means is provided for collecting the digitized
electrical signals at one time to form one image from less than
thirty-three frames of the region of interest in the body. Memory
means is provided for storing the single frame in the memory means
by storing the magnitude and phase angle of each received
electrical signal. Display means is provided. Means is provided for
coupling the single frame to the display means to provide a visual
image of the region of interest in the body.
[0037] More in particular, the ultrasound apparatus 21 of the
present invention as shown in FIG. 1 consists of a housing 22 which
is configured in such a manner so that it can be held by a human
hand. The housing 22 is provided with a detachable scan head 23.
The housing 22 is externally shaped as a parallelepiped and is
provided with spaced-apart parallel front and rear walls 26 and 27
and spaced apart and generally parallel side walls 28 and 29. It is
also provided with a top wall 31. The bottom wall is formed by the
detachable scan head 23. The housing 22 and the scan head 23 can be
formed of a suitable material such as plastic.
[0038] A suitable display such as a liquid crystal display 36 is
provided in the front wall. A plurality of control buttons 37, 38,
39 and 41 are provided on the front wall 26 above the display 36
and can be utilized for providing various functions as hereinafter
described.
[0039] The housing 22 and the detachable scan head 23 have housed
therein the electronics shown in FIG. 3. The detachable scan head
23 is one of a plurality of scan heads usable with the housing 22.
As hereinafter explained, the scan heads are for use at different
frequencies for different applications.
[0040] Each of the detachable scan heads 23 includes a transducer
52 which is comprised of a plurality of piezoelectric transducer
elements 53 forming a transducer array. The transducer elements 53
can range in number from 32 and up with multiples thereof as for
example 64, 128 and 256 elements. These elements can be formed of a
conventional ultrasonic transducer material such as PZT. The
transducer elements 53 can be arranged to form specific arrays as
for example a linear array as shown in FIG. 1 to provide a wide
footprint which is particularly useful for fetal monitoring or
peripheral vascular diagnosis. Where a smaller footprint is
desired, a phased array can be utilized for example when making
examinations through spaced-apart ribs of a human body. Also in
certain applications curved arrays can be utilized as hereinafter
described.
[0041] As shown in FIGS. 1 and 2, the detachable scan head 23 is
provided with a rectangular window 51 sized for a linear array and
can have dimensions such as a width of 25 to 30 mm and a length of
approximately 100 mm in which a transducer 52 is disposed and which
is comprised of the plurality of ultrasonic transducer elements 53
to form an array of the desired configuration extending the length
and width of the window 51. This array of transducer elements 53
are arranged in a conventional manner and are juxtaposed over an
acoustic backing layer 54. The transducer elements 53 are connected
in a conventional manner by conductors 56 to a printed circuit (PC)
board 57 mounted within the scan head 23. Semiconductor switching
devices 58 of a conventional type are mounted on the PC board 57
and are connected to a conventional high density, low force female
connector 61 mounted in the scan head 23. A non-volatile memory
device 59 of a suitable type such as an EEPROM is also mounted on
the PC board 57. The nonvolatile memory device 59 contains the
program information with respect to the selected transducer and/or
application configuration to program the electronics in the housing
so that it is adapted to operate with the specific transducer array
provided in the selected scan head.
[0042] A combination impedance matching layer and lens 66 formed of
a suitable plastic transparent to ultrasonic energy is mounted in
the window 51 and overlies the transducer 52. It is provided with a
surface 67 which is adapted to engage the surface of the tissue of
the body in the region of interest to be examined by the ultrasonic
apparatus as hereinafter described. The matching layer and lens 66
has a y dimension which corresponds to the length of the array and
an x dimension which corresponds to the width or front-to-back
dimension of the array. The matching layer and lens 66 provides a
fixed focus which typically has a focus near the far field or in
other words near or beyond the maximum depth that the ultrasonic
signal will be used to try to image the tissue while scanning in
the orthogonal plane.
[0043] Cooperative means is provided for attaching the detachable
scan head 23 to the housing 22 and consists of first and second
upwardly and outwardly extending spring-like latch arms 71 disposed
on opposite ends of the scan head 23. The arms 71 carry hooks 73 at
their outermost extremities which can snap onto ledges 74 provided
in the side walls 28 and 29 of the housing 22. Flanged knobs or
push buttons 76 are mounted in the side walls 28 and 29 of the
housing 22 for pushing the hooks 73 of the latch arms 71 off of the
ledges 74 to release the scan head 23.
[0044] As the scan head 23 is pushed into the housing 22, a
connection is made between the female connector 61 carried by the
detachable scan head 23 and a corresponding male connector 81
provided in the housing 22. The male connector 81 is connected to
the electronics within the housing 22 in a conventional manner. The
scan head 23 can be detached by pressing inwardly on the arms 71
and 72 so that the hooks 73 clear the holes 76 permitting the scan
head to be detached and at the same time separating the female
connector 61 from the male connector 81, permitting the user to
attach a different scan head 23 as desired by the user and as
hereinafter explained.
[0045] Another detachable scan head is shown in FIG. 3 and is
identified as a scan head 23a which is constructed in a manner
similar to the scan head 23 hereinbefore described with the
exception that the window 51a provided therein has a lesser length
than the window 51 and typically can be approximately square and
having an opening of approximately 25 mm.times.25 mm to receive a
phased array rather than a linear array. A similar type of
construction could be utilized for a curved array.
[0046] The electronics utilized in the ultrasound apparatus 21 is
shown in FIG. 4 and in which the transducer array 52 is shown in
contact with an image target 101 which by way of example can be
tissue within a human body or tissue such as shown on the outer
surface of the human body. The transducer array 52 is connected by
a number of channels corresponding to the number of elements in the
array to a transmit and receive switch 102, if used, typically
containing a plurality of diodes that are biased on an off to
perform switching between transmit and receive modes for the
transducer elements 53. During the transmit mode, drive profile
generation is supplied from a block 106 to a drive profile block
107 that controls a power amplifier 108 to supply energy through
the transmit and receive switch 102 to the transducer elements of
the transducer array 52 to cause ultrasonic energy in the form of a
drive signal to be supplied into the tissue in the region of
interest. Reflected ultrasonic energy in the form of a reflected
signal reflected from the tissue in the region of interest is
picked up by the transducer elements 53 of the transducer array. By
way of example using 64 transducer elements 53 in the array of the
scan head 23, drive signals can be delivered to 16 of the 64
transducer elements with time delay for focusing ultrasonic energy
into a region of interest in the tissue. Reflected ultrasonic
signals are picked up by all 64 of the transducer elements.
[0047] Reflected electrical signals from the transducer elements 53
are supplied to the transmit and receive switch 102 during the
receive mode. The reflected signals are supplied to a time-gain
correction block 111 which is used to compensate for
scattering/attenuation of ultrasonic energy when penetrating deeper
into the tissue. Thus the signals from the far field in the tissue
are amplified in accordance with time to compensate for these
losses. This time-gain correction 111 is adjustable and under user
control from the time gain control (TGC) ramp profile provided in
block 106 and supplied by the digital to analog (D/A) converter
112. Thus, a digitally synthesized analog ramp is created which is
used for controlling the time-gain correction block 111. This TGC
ramp profile provided by the digital signal processor 106 is under
the control of a microprocessor 116 which is provided with a
graphical user interface. Typically, the gain is increased as
deeper penetration into the body is desired. The depth of
penetration of course is dependent upon the detachable scan head 23
selected for the procedure.
[0048] The received reflected signals after being time-gain
corrected are supplied to a quadrature mixer 121 which receives a
local oscillator signal from the local oscillator in block 6. The
local oscillator generates at a higher frequency than the frequency
of the reflected signal. The mixer 121 delivers two heterodyne
lower frequency signals at a frequency which is the difference
between the reflected signal frequency and the local oscillator
frequency and identified as I and Q signals with the I signal
having a zero phase shift and the Q signal having a 90.degree.
(quadrature) phase shift. These two signals from the mixer 121 are
supplied to analog to digital (A/D) converters 123 with one
converter for the in-phase signal I and the other for the
quadrature signal Q. The converted analog-to-digital signals are
then supplied to a field programmable gate array 106. A suitable
gate array has been found to be one supplied by Xylinx selected
from the Virtex series. As shown in the block 106, this
programmable gate array has a number of capabilities. For example
it has a built-in memory and signal processing capabilities. It
also has capabilities for generating the drive profile as well as
generating the time-gain correction ramp profile. The memory
provided has the capability of storing the incoming signals for
period of time which is at least sufficient to collect the data for
one frame with the time of collection being directly proportional
to the depth of penetration of the ultrasonic energy in the image
target 101. When it is found desirable, the gate array 106 can be
utilized for collecting additional raw data from the A/D converters
123 as for example for collecting the raw data for additional
frames as for example 2 and 4 but typically less than 6 frames and
then averaging the raw data to provide improved signal-to-noise
data for the one frame. This averaged raw data can then be stored
in the same memory location. Thus the user has the capability of
selecting averaging from the desired number of frames.
[0049] Thus, the gate array 106 serves as a data buffer and stores
the raw data until it is needed for image construction which is
performed in the image construction block 131 by use of a digital
signal processing (DSP) chip. One such chip found to be
satisfactory is Model No. 320TMS6203 manufactured by Texas
Instruments. The image construction by the DSP chip is carried out
by analyzing the amplitudes of the acoustic signals being received
to provide a gray scale. The operation of the digital signal
processing chip 131 can be best explained by reference to the flow
chart shown in FIG. 5 which describes a method by which ultrasound
image reconstruction is performed in accordance with the present
invention and as hereinafter described. Image construction is only
one of the functions performed by the DSP chip 131. Zoom function,
Doppler processing and color flow can be implemented through the
DSP chip 131 under the control of the microprocessor 116. In the
Doppler processing as is well known to those skilled in the art,
frequency shifts between the received signal and the transmitted
signal are analyzed.
[0050] The microprocessor 116 is provided with user interface and
user input capabilities. It also has controls for providing frame
averaging and is connected to the programmable gate array 106 to
make accessible to the user frame averaging capabilities. The user
inputs 137 as shown in FIG. 4 include ON/OFF, TGC, zoom, and
Doppler functions with which the user can interface.
[0051] The frame averaging which is under the control of the
microprocessor 116 differs from the frame averaging described in
connection with the gate array 106 that is performed with raw data.
The frame averaging by the microprocessor 116 is provided by
averaging video frames after image construction and is for the
purpose of smoothing the transition between frames.
[0052] A frame memory 141 is provided which is coupled to the
microprocessor 116 for storing a plurality of frames as for example
4 to 8 frames so that they can be recalled. Thus by way of example
the last 5 to 8 frames can be saved in the memory for recall.
[0053] A power supply is provided for the electronics as shown in
FIG. 4 and as shown therein consists of a battery 146 of a suitable
type as for example a 9 volt dc battery which supplies its output
to a regulator 147 to provide a regulated power supply for all of
the electronics in the system as shown in FIG. 4. The power supply
also includes a power management block 148 which is provided for
controlling the power supplied by the battery 146 to greatly
conserve battery power use. This makes possible the use of a
battery having a smaller size and/or a longer life. This is made
possible because all or substantially all of the semiconductor
chips utilized in the electronics are provided with another
terminal which can be identified as a power down or a sleep mode
terminal. The microprocessor 116 acting through the power
management block 148 makes decisions when certain devices i.e.
parts of the electronics have performed their function and places
them in sleep modes until needed to consume power. For example,
when a gated burst of ultrasonic energy has been fired into the
image target, the power amplifier 108 and the drive profile 107 and
associated electronics can be placed in the sleep mode for low
power consumption until it is time to fire another gated burst into
the image target. Similarly, the time-gain correction 111, the
mixer 121, and the A/D converters 123 can be placed in sleep modes
once they have collected the data and supplied it to the gate array
106 only the microprocessor 116 runs continuously since it is
performing the power management. In other words, in the image
construction on the display 36, all of the analog signal processing
circuitry is powered down more than approximately 90% of the time
the ultrasound apparatus is in operation.
[0054] The microprocessor 116 supplies the image created by digital
signal processor 131 to the display 36 which as explained
previously can be in the form of a liquid crystal display as shown
in FIG. 1. An encoder (not shown) may be provided which can be
connected to the microprocessor 116 for encoding the images on the
display 36.
[0055] Auxiliary capabilities are provided in the electronics shown
in FIG. 4 which are included within a dotted line rectangle 152. In
block 153 provided therein, image construction, Doppler processing
and color flow capabilities of the digital signal processor 131 are
duplicated and supplied to an external display adapter 154 which is
under the control of the microprocessor 116. The external display
adapter 154 supplies data to an external display 156 which by way
of example can be a large-size liquid crystal display or a
conventional cathode ray tube monitor. The data is also supplied to
a data storage 157 which can be utilized to provide hard copy or
alternatively to store it or to supply it to a videocassette
recorder or a Polaroid.RTM. camera.
[0056] Operation and use of the miniaturized ultrasound apparatus
of the present invention and the method of the present invention
can be described in conjunction with the flow chart shown in FIG.
5. Let it be assumed that it is desired to perform ultrasound
diagnostic testing on a patient in a physician's office as for
example for exploring tissue in the abdominal area serving as the
image target 101. The physician takes the ultrasound apparatus 21
as shown in FIG. 1 and grasps with a hand and with a finger of that
hand depresses the ON/OFF button 37 to energize the electronics.
The desired detachable scan head 23 has been selected and attached
to the housing 22. The non-volatile memory device 59 provided in
the detachable scan head 23 programs the electronics with the
housing 22 of the requirements for powering the scan head 23 within
a power up time period.
[0057] The surface 67 of the detachable scan head 23 is then placed
in contact with the skin of the patient overlying the abdominal
area to view the tissue of interest forming the image target 101.
An image appears on the liquid crystal display 36 depicting the
tissue of interest being viewed. Movement of the hand-held
ultrasonic apparatus 21 by the physician over the skin of the body
in a desired direction will cause additional images to appear upon
the liquid crystal display 36 thereby supplying to the physician
various views of the image target of the patient dependent upon the
position of the detachable scan head 23.
[0058] In operation of the electronics, drive profile generation
from the gated array 106 supplies a gated burst of at least one,
preferably three to five cycles but typically less than six cycles,
of the frequency of the selected scan head 23 to the drive profile
block 107. The drive profile 107 serves as a buffer and feeds the
power amplifier 108 which supplies an amplified gated burst of
cycles to the transmit and receive switch 102 and thence to the
transducer 52 to provide corresponding transducer excitations to
produce ultrasonic pulses which are directed toward the tissue in
the region of interest in the image target 101. In order to improve
the performance of the apparatus in achieving high resolution
images, it may be desirable to improve the signal-to-noise ratio by
focusing the ultrasonic energy being introduced into the body by
conventional beam forming techniques. Typically, this is
accomplished by inserting appropriate time delays to selectively
insonify sequential portions of the tissue in the target 101. In
this way, selective regions of the tissue of interest can be
insonified in a desired sequence.
[0059] Ultrasonic signals are reflected by the tissue in the region
of interest and returned to the transducer 52 where they are
converted into electrical signals which pass through the transmit
and receive switch 102. It should be appreciated that if desired, a
separate transducer can be utilized for transmission and another
transducer utilized for reception rather than utilizing a single
transducer as for example transducer 52 for performing both
transmission and reception in connection with the transmit and
receive switch 102.
[0060] The electrical signals from the transmit and receive switch
102 as hereinbefore pointed out pass through the TGC amplifier 111
through the mixer 121 to provide the in-phase and out-of-phase
components I and Q of the electrical signals in an analog format.
These analog signals are digitized in the A/D converter 123 and
supplied to the memory in the gate array 106 where they are
collected to form the image for a single frame of the tissue in the
body from a single transducer excitation or when desired a
plurality of transducer excitations less than six. This memory
stores the electrical signals for the single frame by storing the
magnitude and phase angle and time of receipt of each received
electrical signal.
[0061] In the image construction performed in the digital signal
processor 131, the steps set forth in FIG. 5 are performed. Thus as
shown in step 161 there is selected a wave packet in space of the
stored electrical signals having sample points therein which are
centered around a selected point (x,y) to be calculated. Thereafter
as shown in step 162 the distance to the wave packet center around
(x,y) from the selected ultrasonic element in the ultrasound
transducer 52 identified as (i) is calculated. Since d=rt and t=d/r
where d is distance, r is rate of travel and t is time of travel,
the time of travel from the tissue sample under examination can be
determined by taking the known distance of travel and dividing it
by the rate of travel. Distance is ascertained by using the known
rate of travel of ultrasonic energy in tissue and multiplying it by
time to obtain distance. Thereafter as shown in step 163 distance
is converted to time to select the sample points. This is followed
by step 164 by interpolating the phase and magnitude between the
nearest sample points and the point to be calculated to determine
the corrected phase and magnitude for that point being calculated.
Thereafter, as indicated by the feedback loop 166, these same steps
are performed for each of the ultrasonic elements in the array of
the transducer. After all of the points have been calculated, these
points are summed as shown by step 167 by considering the direction
and magnitude of each vector representing a calculated point to
provide a pixel value.
[0062] Thereafter, after the steps 164, 166 and 167 have been
performed, x and y are incremented as shown by feedback loop 168
typically in an orderly fashion and one at a time to obtain the
center of the next wave packet to be calculated until all of the x
and y points have been calculated in the manner hereinbefore
described. The x and y parameters are selected to provide the best
image. For example, they can define a square, a rectangle or an
oval shape to achieve the best image. By way of example with a 64
element transducer, five different points can be selected for each
element to provide 320 points which are summed to create the
desired calculated point. This procedure is continued for every
point in the field of view to provide a fully constructed
image.
[0063] After these steps have been accomplished, post processing
steps can be performed as shown in FIG. 5. Thus as shown in step
171, a user gray scale correction can be performed to achieve the
desired contrast. In addition image filtering can be utilized to
provide edge enhancement if that is desired. Further conventional
post processing steps can also be utilized which can include
Doppler processing and color flow. Also as shown in FIG. 5 in step
172, image data can be supplied to a display driver or
processor.
[0064] In accordance with the present invention it can be seen that
digitized electrical signals are collected to form one image in a
single frame of the tissue in the region of interest from a single
transducer excitation which creates a certainty in the image. As
explained previously, if desired additional transducer excitations
less than thirty-three can be averaged for this single frame. This
makes it possible to construct an image at a much higher rate in a
much shorter time due to the fact that it is only necessary to
collect a minimum amount of data i.e. that from a single transducer
excitation or at most less than six excitations to construct the
image. Since all the information is in this single frame, there is
an ability to zoom in, up to the resolution of the transducer
array. The apparatus and method of the present invention make it
possible to provide a frame rate which is substantially higher than
a conventional frame rate of 32-35 frames per second as for example
from 3000 to 7000 frames per second.
[0065] With the image being constructed in the manner of the
present invention with typically that digitized data only being
collected for the image from a single transducer excitation, there
is a reduced dosage of ultrasound energy to the patient. By the
utilization of detachable scan heads, it is possible to readily
select the frequency of operation and to change from a linear array
to a phased array or to a curved array while retaining the same
housing and electronics. Thus in the apparatus 21 there is created
a modular unit which has various capabilities for diagnostic
ultrasonic imaging and making it possible to create various
images.
[0066] Another embodiment of an ultrasound apparatus incorporating
the present invention is an ultrasound-guided probe placement
apparatus 201 which is shown in FIG. 6. This apparatus includes a
probe guide 202 formed of a suitable material such as plastic. The
probe guide 202 consists of a body 203 which is provided with first
and second parallel spaced-apart forwardly extending legs 206 and
207 that are formed integral with the body 203. The body 203 and
the adjoining legs 206 and 207 are provided with a continuous lower
planar surface 208 which is adapted to be placed in engagement with
the skin of the patient and being movable on the skin of the
patient. The body 203 is provided with an elongate transversely
extending recess 211 which is formed to receive the scan head 23 of
the ultrasound apparatus 21 hereinbefore described and to retain it
in an angular position as for example at an angle of 45.degree.
with respect to the planar surface 208. The recess 211 opens
through the bottom planar surface 208 so that the scan head 23 can
come in contact with the surface of the skin 209 overlying the
tissue in the region of interest in the body.
[0067] A carriage 213 is slidably mounted on the legs 206 and 207
and is movable along the length of the legs. The carriage 213 is
generally in the form of a planar member 214 extending across a
space 216 which is provided with a pair of spaced-apart depending
flanges 217 on opposite ends of the planar member 214 and engaging
the outside surfaces of the legs 206 and 207. Openings 218 are
provided in planar member 214 overlying the upper surfaces of the
legs 206 and 207 to make visible spaced-apart scaling indicia 219
provided on the upper surfaces of the legs 206 and 207. The indicia
219 provided on the top surfaces provide a scale reading in an
incremental manner as for example from 1 to 9 on each of the legs
in a direction extending away from the body 203 towards the
forwardmost extremities of the legs 206 and 207. A probe guide
member 221 is formed integral with the planar member 214 and
extends upwardly and forwardly therefrom at a suitable angle as for
example of 45.degree.. The probe guide member 221 is provided with
a longitudinally extending recess 222 which is approximately
semicircular in cross section. The recess 222 is sized so as to be
adapted to receive probes of various sizes such as a hypodermic
needle 226 having a sharpened tip 227 and which has a syringe 229
mounted thereon. The syringe 229 can be operated by hand for
withdrawing blood.
[0068] The display 36 is provided with a scale 231 corresponding to
the scale formed by the indicia 219 and also reading incrementally
as for example from 1 to 9 from the top of the screen to the
bottom. The display 36 is provided with a vertically extending line
233 centrally disposed between the sides of the display 36 and
which is in alignment with the recess 222 provided in the probe
guide 221.
[0069] Let it be assumed that it is desired to utilize the
apparatus 201 as shown in FIG. 6 for withdrawing blood from a
vessel below the skin of a patient as for example from a vein. The
probe guide 202 of the apparatus 201 moved therein is moved over
the skin 209 of the patient until the desired image appears on the
screen 36. The probe guide 202 is positioned so that the image is
lined up with the line 233 and is centered on the line 233. Then by
observing the scale 231 and the position of the image with respect
to the scale, the carriage 213 is moved to the same numerical
position on the scale 219. The needle or probe 226 can then be
placed in the recess 222 or alternatively the probe 226 can prior
thereto be placed in the recess 222. The needle 226 can be
introduced through the skin 209 at an angle determined by the probe
guide member 221 and thence into the target tissue 236. This
movement into the target tissue can be observed on the display 36.
As soon as the target tissue 101 has been accessed, the planned-on
operation as for example the withdrawal of blood, a biopsy or other
procedure can be carried out utilizing a probe positioned by the
use of the probe guide member 221. As soon as the procedure has
been completed, the probe or needle 226 can be withdrawn, after
which the probe guide 202 can be removed and placed in a different
location if so desired.
[0070] Another embodiment of the ultrasound apparatus incorporating
the present invention is shown in FIGS. 7 and 8. The ultrasonic
apparatus 251 as shown therein is very similar to the ultrasound
apparatus hereinbefore described in FIGS. 1, 2 and 3 with the
principal difference being that the apparatus is separated into two
units, one being identified as a main module 252 and the other
being identified as a display module 253. These modules are
provided respectively with housings 256 and 257 which are generally
sized so they can fit in a human hand. The main module 252 is
provided with a detachable scan head 258 similar to the detachable
scan head 23 hereinbefore described. In accordance therewith it is
provided with a window 259 which has a transducer 261 provided
therein of the type hereinbefore described which is covered with a
matching layer and lens 262 of the type hereinbefore described.
[0071] The housing 257 of the display module 253 is provided with a
window 266 in which there is provided a liquid crystal display 267
similar to the LCD display 36 hereinbefore described. The housing
257 is also provided with a slot 268 for receiving a printed
circuit card as for example an industry standard PCMCIA card. A
connector 269 is mounted in the housing 257 and serves as a printer
port for connection to a printer for printing out hard copy when
that is desired. The card slot 268 also can be used for receiving a
memory card for storing images for later use in a personal computer
or a notebook computer.
[0072] Means is provided for establishing communication between the
main module 252 and the display module 253 and consists of an
umbilical cord 271. This umbilical cord 271 can be of any suitable
type. To provide improved flexibility it is desirable to utilize a
fiber optic cord for communication between the two modules.
However, it should be appreciated that other types of an umbilical
cord can be utilized as for example an electrical multi-conductor
cable can be utilized. Alternatively in order to give greater
flexibility and to avoid the use of a cord, a radio frequency or an
infrared link can be provided between the two modules so that the
display module 253 is physically free and separate from the main
module 252. In this way, the main module 252 can be coupled to a
wall hung display unit or alternatively connected to a conventional
CRT monitor.
[0073] The main module and display module 252 and 253 can be
removably fastened together as shown in FIG. 8 in a clam-shell-like
fashion in a suitable manner as for example by placing Velcro.RTM.
strips on the back sides of each of the housings 256 and 257 so
they can be fastened together and carried as a unit while being
readily separable from each other during use.
[0074] In use of the apparatus shown in FIGS. 7 and 8, the main
module 252 can be taken by one hand of the physician and moved over
the patient's body while the display module 253 can be held in the
other hand. This makes it much easier for the physician because the
display module can be held in front of his face so it is readily
visible while the main module is being moved over the patient's
body in locations which would make it difficult for the physician
to observe the display if it were on the main module itself.
[0075] The electronics utilized in the ultrasound apparatus 251
would be very similar to the electronics used in the apparatus 21
hereinbefore described with the electronics being principally
disposed within the main module 253 but interconnected by the cord
271 to any electronics provided in the display module. The controls
272 providing the user interface typically would be provided on the
main module 252. However, it should be appreciated that if desired
at least some of the controls if desired could be provided on the
display module.
[0076] In certain applications of the ultrasonic apparatus of the
present invention it may be desirable to obtain multiple images of
the target tissue to make possible a kinetic display to aid the
physician in making a diagnosis. Ultrasonic apparatus 301 utilized
for such a purpose is shown in FIG. 9. As shown therein, the
ultrasound apparatus 301 has a housing 302 of the type hereinbefore
described which is adapted to be held by the human hand and which
is provided with a detachable scan head 303. The housing 302 and
the scan head 303 can be generally of the same type as housing 22
and the detachable scan head 23 hereinbefore described. The scan
head 303, however, is provided with a triggering mechanism 306 so
that an image set will only be taken when a triggering event has
occurred rather than taking images continuously as for example at
20 frames a second. The triggering mechanism 306 is utilized to
create images at different spatial intervals which are recorded in
memory so that they can be played back in an endless loop fashion
to provide a kinetic image of the tissue being visualized. Thus, by
way of example if a tumor in the body is being imaged, taking
images at different spatial intervals at different times makes it
possible to ascertain whether or not a tumor is growing or
shrinking.
[0077] As shown in FIG. 9, this triggering mechanism 306 can
consist of an attachment 307 provided at one end of the scan head
303 and as shown forming an integral part thereof. This attachment
307 includes a T-shaped foot 309 that is slidably mounted in a
T-shaped slot 311 provided in an elongate support member 312 that
serves as a support and guide for the scan head 303 and the housing
302 to which it is attached. The support member 312 is provided
with a lower surface 313 which is adapted to be placed upon the
skin overlying the tissue of the human body being examined. When so
positioned, the attachment 307 with its scan head and housing 303
and 302 can be moved longitudinally of the member in the T-shaped
slot 311 in either of two directions as shown by arrows 316.
[0078] The trigger mechanism 306 also includes means for triggering
sequentially the electronics provided in the housing 302 and the
scan head 303 at different spatial intervals. This triggering means
can be of any suitable type as for example an optical scanner 321
carried within the scan head adjacent the attachment 307 and
viewing an exterior planar generally vertical surface 322 extending
the length of the support member 312 and having provided thereon a
scale 323 in the form of a plurality of equally spaced-apart
vertical marks 324 which by way of example can be black or another
opaque color to stand out visually from the background of the scale
323 to provide contrast to make them readily visible to the optical
reader or scanner. By providing such a scale 323 on the support
member 312, the support member also serves as a ruler. Thus if
desired, another support member 312 can be provided with a scale
323 which has marks which are spaced apart in a different manner.
For example one ruler could have marks which are more closely
spaced to take multiple images of a relatively small body of tissue
as for example a small organ. Alternatively, another ruler could
have a scale provided with marks which are further apart for taking
sequential images of a relatively large body.
[0079] Operation and use of the ultrasound apparatus 301 may be
briefly described as follows. Let it be assumed that it is desired
to image an organ in the patient as for example in the abdominal
region. The physician need merely grasp the housing 302 by the hand
and then place the support member 312 on the skin of the patient
and having the scan head 303 engage the skin of the patient at the
same time. Sequential images can then be obtained and stored in the
memory by moving the housing 302 with the attachment 307 carried by
the scan head 303 be moved longitudinally of the support member 312
having the scale 323 thereon to cause sequential images to be taken
of the organ or tissue being analyzed under the skin of the
patient. Since the triggering of the images is under the control of
the bars or marks carried by the scale 323, the images will be
taken at different spatial intervals of the organ and will be
spaced apart equally regardless of the speed of movement of the
scan head 303 relative to the scale 323 carried by the support
member 312. The images so taken can be stored in a random access
memory card carried in the housing 302 as hereinbefore described.
These images can also be stored in the memory within the
electronics of the ultrasonic apparatus and then can be replayed to
display a kinetic image on the display 326 carried by the housing
302. Alternatively, the nonvolatile random access memory card can
be removed and inserted into a notebook computer or other device to
display the successive images to obtain a kinetic image of the
organ being examined.
[0080] As also explained previously, depending on the size of the
organ, different spatial intervals can be selected depending on the
size of the organ by merely exchanging the support member 312 being
utilized. Support members 312 providing the desired spacing can
then be substituted one for the other to obtain the desired kinetic
imaging.
[0081] It should be appreciated in connection with the present
invention that various types of triggering devices can be utilized.
For example a mechanical wheel traveling with the housing could be
utilized for triggering the image taking. Magnetic triggering also
could be readily used in such a device.
[0082] Another embodiment of the ultrasonic apparatus of the
present invention making possible kinetic imaging is shown in FIG.
10. The ultrasound apparatus 331 shown therein consists of a
housing 332 with a detachable scan head 333 of the type
hereinbefore described. The triggering mechanism 336 of this
embodiment of the ultrasonic apparatus 331 includes first and
second pairs of spaced-apart triangular shaped feet 337 and 338
provided on opposite ends of the scan head 333. The feet 337 and
338 are pivotably connected to the scan head 333 by pins 339. The
feet 337 and 338 have lower planar surfaces 341 which are spaced
apart and are parallel to each other and are generally in alignment
with the lower extremity of the scan head 333. An optical reader
346 is carried by one end of the scan head 333 and is adapted to
view an arcuate scale 347 in the form of angularly spaced apart
marks 348 carried by the interior surface of the foot 338 and being
visible to the optical reader 346. The marks 348 are angularly
spaced apart so that as the housing and the scan head 332 and 333
are pivoted with respect to the pins 339 carried by the feet 337
and 338, the optical reader will sequentially view the marks to
cause triggering of the electronics and the taking of successive
images spaced apart equally approximately radially in a
sector-shaped scan of the tissue. Scans which are more closely
spaced in distance or farther apart radially can be achieved by
replacing the foot 338 with other feet having different scales
thereon which can be scanned by the optical reader 346. As
explained previously, these images can be stored in the memory
within the electronics or alternatively can be stored in a separate
non-volatile memory card inserted into the housing 332 and
thereafter viewed at a separate location on a separate apparatus as
for example a notebook computer. Such sector-shaped kinetic imaging
may be very desirable where it is difficult to achieve linear
imaging because of space constraints. For example sector-shaped
kinetic imaging may very well be appropriate for imaging carotid
vessels.
[0083] Kinetic imaging is used as a method of approximating
3-dimensional space with 2-dimensional images by making a plurality
of images of an organ being examined along the length of the organ
at equal distance intervals. The resulting images are played back
sequentially and provide a sense of 3-dimensional imaging of the
organ in the selected location. Cannulas and probes can be
accurately guided into the appropriate depth of penetration by
aligning the target with the ultrasound displayed image. The
apparatus and method of the present invention is particularly
useful for emergency medicine. It also can be very useful in
obstetrics and gynecology, soft tissue biopsies, vascular access
and cardiology.
[0084] Still another ultrasound apparatus incorporating the present
invention is the ultrasound apparatus 351 is shown in FIG. 11. This
ultrasound apparatus 351 also includes a hand-held housing 352 of
the type hereinbefore described which encloses the electronics also
hereinbefore described. The ultrasonic transducer rather than being
carried by a detachable scan head attaching to the housing is
carried in a probe 353 connected by a cable 356 to the housing. The
probe 353 consists of a handle 361 which is of a length and size
adapted to fit in the palm of the hand. The handle 361 is provided
with a slider 362 slidably mounted therein longitudinally of the
handle and is provided with an upwardly extending knob 363 which
extends through an elongate slot 364 provided on the top side of
the handle 361 and accessible by the thumb of the hand grasping the
handle 361 for moving the knob 363 within the slot 364. A rigid
shaft 366 is secured to the slider 362 and is slidably movable with
the slider 362 and carries a probe head 367 which is provided with
a conical tip 368. A transducer (not shown) is provided within the
probe head 367 and can be of a conventional type. It can either be
a linear transducer or a sector scan transducer.
[0085] A flexible cable 369 extends from the transducer and is
connected into the cable 356. A trigger mechanism 371 of the type
hereinbefore described is incorporated in the handle 361 and as
shown can take the form of an optical reader 372 connected by
conductors 373 to the electronics in the housing 352. The optical
reader is provided for scanning a scale 374 underlying the slider
362 and which is provided with a plurality of longitudinally
spaced-apart marks underlying the slider 362. Thus, as the slider
is moved by operation of the knob 363 to cause longitudinal
movement of the probe head 367, images are taken at spaced-apart
distances. As in the previous embodiments, these images will be
spaced apart in the tissue being examined at desired distance
intervals independent of the speed of movement of the slider 362
under the control of the knob 363. As in the previous embodiments,
these images can be played back to provide a kinetic image or
alternatively can be viewed at a separate location by removal of
the non-volatile memory card and using it for example in a portable
computer. The ultrasound apparatus 351 provided in FIG. 11 can be
utilized in a number of medical applications as for example in
transrectal or transvaginal imaging as well as a variety of other
applications in urology such as examining the prostate or examining
parts of the alimentary canal.
[0086] It is apparent from the foregoing that there has been
provided an ultrasound apparatus which has been miniaturized so it
is very compact and is relatively simple to operate. The method of
forming a frame by collecting all of the data utilized for making
the image of a frame from transducer excitations less than
thirty-three in number, preferably only one, greatly reduces power
consumption. The electronics described makes it possible to
increase the visual resolution obtainable to the inherent
resolution of the transducer array. The electronics described also
makes it possible to export the preprocessed data to be processed
in an optimized fashion for display in a higher or lower resolution
display unit.
* * * * *