U.S. patent application number 10/003666 was filed with the patent office on 2002-05-16 for volumetric image ultrasound transducer underfluid catheter system.
This patent application is currently assigned to Mayo Foundation for Medical Education Research. Invention is credited to Seward, James Bernard, Tajik, Abdul Jamil.
Application Number | 20020058873 10/003666 |
Document ID | / |
Family ID | 32046202 |
Filed Date | 2002-05-16 |
United States Patent
Application |
20020058873 |
Kind Code |
A1 |
Seward, James Bernard ; et
al. |
May 16, 2002 |
Volumetric image ultrasound transducer underfluid catheter
system
Abstract
An underfluid ultrasound imaging catheter system includes a
catheter having a distal end inserted into an underfluid structure,
an ultrasonic transducer array mounted proximate the distal end of
the catheter wherein the array has a row of individual transducer
crystals, a lens mounted on the array for defocusing ultrasound
beams in a direction perpendicular to an axis of the array so as to
provide a volumetric field of view within which the underfluid
features are imaged. Alternatively, the single row of transducer
crystals is replaced by multiple rows of transducer crystals so as
to provide a volumetric field of view. This imaging catheter system
helps an operator see 3-dimensional images of an underfluid
environment, such as the 3-dimensional images of fluid-filled
cavities of heart, blood vessel, urinary bladder, etc. Features in
such wide volumetric field of view can be imaged, measured, or
intervened by an underfluid therapeutic device with an aid of the
real-time image.
Inventors: |
Seward, James Bernard;
(Rochester, MN) ; Tajik, Abdul Jamil; (Rochester,
MN) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
Mayo Foundation for Medical
Education Research
Rochester
MN
|
Family ID: |
32046202 |
Appl. No.: |
10/003666 |
Filed: |
October 23, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10003666 |
Oct 23, 2001 |
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09586193 |
Jun 2, 2000 |
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09586193 |
Jun 2, 2000 |
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09087520 |
May 29, 1998 |
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09087520 |
May 29, 1998 |
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09003248 |
Jan 6, 1998 |
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09003248 |
Jan 6, 1998 |
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08678380 |
Jun 28, 1996 |
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08678380 |
Jun 28, 1996 |
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08305138 |
Sep 13, 1994 |
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08305138 |
Sep 13, 1994 |
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07972626 |
Nov 6, 1992 |
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07972626 |
Nov 6, 1992 |
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07790580 |
Nov 8, 1991 |
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Current U.S.
Class: |
600/466 |
Current CPC
Class: |
A61B 2017/00243
20130101; A61B 8/4488 20130101; A61B 8/445 20130101; A61B 8/06
20130101; A61B 8/12 20130101; A61B 17/320758 20130101; A61B
2090/3784 20160201; A61B 2090/378 20160201 |
Class at
Publication: |
600/466 |
International
Class: |
A61B 008/14 |
Claims
What is claimed is:
1. A catheter apparatus, comprising: an elongated body having
proximal and distal ends; an ultrasonic transducer linear phased
array mounted proximate the distal end of the elongated body, the
array transmitting ultrasound beams and receiving resultant echoes,
the array comprising a row of individual transducer segments
aligned generally in an azimuthal dimension; a lens mounted on the
array for defocusing the ultrasound beams such that at least some
of the beams are directed laterally outward in an elevational
dimension which is perpendicular to the azimuthal dimension so as
to provide a volumetric field of view within which flow rates can
be measured and features imaged; and an electrical conductor,
disposed in the elongated body, electrically connecting the
transducer to a control circuitry external of the elongated
body.
2. A catheter apparatus in accordance with claim 1, wherein the
lens is a planoconcave lens made from silicone rubber.
3. A catheter apparatus in accordance with claim 1, wherein the
lens is a planoconvex lens made from a plastic material.
4. A catheter apparatus, comprising: an elongated body having
proximal and distal ends; an ultrasonic transducer linear phased
array mounted proximate the distal end of the elongated body, the
array transmitting ultrasound beams and receiving resultant echoes,
the array comprising a plurality of rows of individual transducer
segments, the transducer segments being phased in both an elevation
direction of the array as well as an azimuthal direction of the
array to produce a volumetric field of view within which flow rates
can be measured and features imaged; and an electrical conductor,
disposed in the elongated body, electrically connecting the
transducer to a control circuitry external of the elongated
body.
5. A catheter apparatus, comprising: an elongated body having
proximal and distal ends; an ultrasonic transducer linear phased
array mounted proximate the distal end of the elongated body, the
array transmitting ultrasound beams and receiving resultant echoes,
the array comprising equal numbers of rows and columns of
individual transducer segments, the transducer segments being
phased in both an elevation direction of the array as well as an
azimuthal direction of the array to produce a volumetric field of
view within which flow rates can be measured and features imaged;
and an electrical conductor, disposed in the elongated body,
electrically connecting the transducer to a control circuitry
external of the elongated body.
6. A catheter apparatus for underfluid imaging, intervention, and
measuring, comprising: an elongated, flexible body having proximal
and distal ends, the distal end being inserted into an underfluid
structure; an ultrasonic transducer linear phased array mounted on
the elongated body proximate the distal end of the elongated body,
the array producing a volumetric field of view of the underfluid
structure in front of the array outside the elongated body, within
which features can be imaged, intervened by a therapeutic device,
and measured; a port disposed in the elongated body extending from
proximate the proximal end to proximate the distal end of the
elongated body for receiving the therapeutic device, the
therapeutic device being operated underfluid in the volumetric
field of view; and means for actuating the ultrasonic transducer
linear phased array.
7. A catheter in accordance with claim 6, further comprising a
guidewire port disposed in the elongated body extending from
proximate the proximal end to proximate the distal end of the
elongated body for receiving a guide wire.
8. A catheter apparatus, comprising: an elongated catheter body
having proximal and distal ends and a longitudinal axis; an
ultrasound imaging system for transmitting ultrasonic beams and
receiving resultant echoes, the ultrasound imaging system including
a transducer array mounted proximate the distal end of the
elongated catheter body and including a plurality of individual
transducer segments aligned along an azimuthal dimension that is
substantially parallel to the longitudinal axis of the elongated
catheter body, the ultrasound imaging system being constructed and
arranged to spread the ultrasonic beams such that the ultrasonic
beams cover a 3-dimensional scanning region, the scanning region
being defined by the azimuthal dimension, a depth dimension
transversely aligned with respect to the azimuthal dimension, and
an elevational dimension transversely aligned with respect to both
the depth dimension and the azimuthal dimension.
9. The catheter apparatus of claim 8, wherein the ultrasound
imaging system includes a lens for spreading the ultrasonic beams
in the elevational dimension.
10. The catheter apparatus of claim 8, wherein the transducer array
includes multiple rows of transducer segments, and the transducer
array is phased in both the elevational dimension and the azimuthal
dimension.
11. The catheter apparatus of claim 8, wherein the transducer array
includes one and one half rows of transducer segments, and the
transducer array is phased in both the elevational dimension and
the azimuthal dimension.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of
U.S. patent application Ser. No. 08/305,138, filed Sep. 13, 1994,
which is a continuation application of U.S. patent application Ser.
No. 07/972,626, filed Nov. 6, 1992, now issued U.S. Pat. No.
5,345,940, which is a continuation-in-part application of U.S.
patent application Ser. No. 07/790,580, filed on Nov. 8, 1991, now
issued U.S. Pat. No. 5,325,860.
BACKGROUND OF THE INVENTION
[0002] Noninvasive ultrasonic imaging systems are widely used for
performing ultrasonic imaging and taking measurements. Such systems
typically use scan heads which are placed against a patients skin.
Exemplary uses for such systems include heart and internal organ
examinations as well as examinations of developing fetuses. These
systems operate by transmitting ultrasonic waves into the body,
receiving echoes returned from tissue interfaces upon which the
waves impinge, and translating the received echo information into a
structural representation of the planar slice of the body through
which the ultrasonic waves are directed.
[0003] Catheter based invasive ultrasound imaging systems,
typically used for intracardiac or transvascular imaging, are a
relatively new addition to ultrasound armamentarian. Conventional
underfluid transducers for use on catheters are comprised of
crystal arrays (e.g. linear phased array) or a single crystal
translated over a surface, producing a tomographic field of view in
an azimuthal plane of the array. Typical arrays include: 1) linear
array (linear sequential array), usually producing a rectangular or
rhomboidal picture; 2) cylindrical array or rotating crystal,
producing a round pie-shaped tomographic cut of structures; and 3)
sector array (linear phased array), producing a triangular shaped
image emanating from a small transducer source. All images are
tomographic in nature and are focused in the azimuthal and
elevation plane. The intent of having these conventional transducer
configurations is to produce a thin ultrasound cut of the insonated
structures. Such tomographic planes by nature are thin and of high
resolution.
[0004] The narrow field of view provided by conventional catheter
transducer configurations is problematic because structures lying
outside of the plane of view can only be visualized by reorienting
or manipulating the catheter. Due to the tortuous and confined
nature of a typical catheter pathway, catheter manipulation is
impractical and often impossible. Consequently, the localization of
specific targets is difficult and at times can be disorienting
because of an inability to appreciate contiguous anatomic
landmarks.
[0005] Advances in 3-dimensional imaging capabilities have been
made with respect to non-catheter related ultrasonic imaging
systems. For example, U.S. Pat. No. 5,305,756, issued to Entrekin
et al., which is hereby incorporated by reference, discloses
general 3-dimensional imaging techniques in a noncatheter based
context. What is needed is a catheter based imaging system that
utilizes 3-dimensional imaging techniques to provide a wide field
of view so as to improve anatomic localization for precision
underfluid diagnostics and interventions.
SUMMARY OF THE INVENTION
[0006] The present invention relates generally to a volumetric,
3-dimensional image ultrasound transducer underfluid catheter
system.
[0007] The present invention also relates to an ultrasonic and
interventional catheter device operated in an intracardiac or
transvascular system, with the aid of a volumetric 3-dimensional
imaging capability.
[0008] In one particular embodiment, the present invention relates
to a catheter apparatus comprising an underfluid catheter body
having proximal and distal ends. An ultrasonic transducer array is
mounted longitudinally along the catheter body proximate the distal
end. The transducer array has a volumetric field of view that
projects radially/laterally outward from the catheter. Features in
such wide volumetric field of view can be imaged, measured, or
intervened by an underfluid therapeutic device with an aid of the
real-time image.
[0009] It is significant that the transducer array described. in
the previous paragraph has a 3-dimensional field of view. A first
dimension, referred to as an azimuthal direction, is aligned with
the length of the transducer array. A second dimension, referred to
as a depth direction, is the depth into the body which an
ultrasonic signal is transmitted and from which an echo return. A
third dimension, referred to as an elevation direction, is
perpendicular to both the azimuthal and the depth directions.
[0010] If the transducer array comprises a linear phased array
having a single row of piezoelectric crystals, a 3-dimensional
field of view can be generated by focusing the ultrasound signals
in the azimuthal direction (parallel to the longitudinal axis of
the catheter) and diverging the ultrasound signals in the
elevational direction (transverse to the longitudinal axis of the
catheter). The ultrasonic signals can be diverged in the
elevational direction through the use of lenses. For example, the
signals can be diverged by mounting a silicone rubber concave lens
or a plastic convex lens in front of the transducer array.
[0011] If the transducer array comprises multiple rows of
piezoelectric crystals, a 3-dimensional field of view can be
generated by electronically phasing the ultrasound signals in both
the azimuthal and elevational directions. Of course, lenses can be
used in association with multiple row arrays to further widen the
field of view.
[0012] It will be appreciated that catheters constructed in
accordance with the principles of the present invention can
optionally include one or more ports that extend longitudinally
through the catheter bodies. The ports are preferably adapted for
guiding therapeutic instruments through the catheter and preferably
have exit ends adjacent to the field of view of the catheter
imaging system. In operation, the ports guide the therapeutic
instruments such that the operative ends of a therapeutic
instruments are directed toward the 3-dimensional field of view of
the imaging system.
[0013] It will also be appreciated that catheters constructed in
accordance with the principles of the present invention can include
one or more guidewire ports which extend longitudinally through the
catheters and are adapted for receiving guidewires.
[0014] One advantage of the present invention is to provide
real-time 3-dimensional images of underfluid features so as to
visualize contiguous anatomy, such as a large volume of tissues
without frequently rotating, flexing, or extending the
catheter.
[0015] Another advantage is that the present invention provides a
much better underfluid "eye"--a 3-dimensional "motion picture"--for
an operator when he/she intervenes the underfluid features by using
an underfluid therapeutic device. These images provide the operator
a direct aid without opening a large area of a body.
[0016] A further advantage is that the present invention have
numerous clinical applications. One is; related to underfluid
imaging: There is a considerable need to increase the field of view
when imaging from within chambers or blood vessels. The physical
space of the chambers or blood vessels is small, and the anatomy in
question is closed approximated and usually totally surrounds the
transducer. A conventional tomographic presentation provides only a
limited slice, thus requiring frequent manipulation of transducer
in order to visualize contiguous anatomy. The present invention is
a solution to visualizing larger volumes of tissue. The underfluid
defocusing transducer array does not appreciably affect the
electronics and does not require alteration in the display format.
The catheter apparatus is immersed in fluid, a homogeneous, low
scattering medium, which is an ideal environment for this
particular transducer modification.
[0017] Another main clinical application is related to underfluid
intervention: In diagnostic and therapeutic procedures, there is an
increasing need for volumetric 3-dimensional visualization which
would improve anatomic localization and recognition of continuous
structures and events.
[0018] A further advantage of the present invention is that by
using such a catheter system, major surgical procedures can be
avoided. It dramatically reduces the patient's physical pain in
operation and mental distress after operation due to any large
visible scars, etc.
[0019] These and various other advantages and features of novelty
which characterize the invention are pointed out with particularity
in the claims annexed hereto and forming a part hereof. However,
for a better understanding of the invention, its advantages and
objects obtained by its use, reference should be made to the
drawings which form a further part hereof, and to the accompanying
descriptive matter, in which there is illustrated and described a
preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] A better understanding of the construction and operational
characteristics of a preferred embodiment(s) can be realized from a
reading of the following detailed description, especially in light
of the accompanying drawings in which like reference numerals in
the several views generally refer to corresponding parts.
[0021] FIG. 1 is a partial perspective view of an embodiment of a
catheter in accordance with the principles of the present
invention;
[0022] FIG. 2 is an enlarged cross-sectional view taken proximate
the distal end of the catheter shown in FIG. 1;
[0023] FIG. 3 is a block diagram in part and sectional diagram in
part illustrating an embodiment of a system utilizing the catheter
shown in FIG. 1;
[0024] FIG. 4A is an illustration illustrating an application of a
catheter in accordance with the principles of the present
invention;
[0025] FIG. 4B is a partially enlarged illustration of the catheter
shown in FIG. 4A.
[0026] FIG. 5A shows a partial perspective and cross-sectional view
of a first alternate embodiment of a catheter in accordance with
the principles of the present invention;
[0027] FIG. 5B shows a view of the distal end of the embodiment of
the catheter shown in Figure 5A;
[0028] FIG. 6A shows a partial perspective and cross-sectional view
of a second alternate embodiment of a catheter in accordance with
the principles of the present invention;
[0029] FIG. 6B shows a view of the distal end of the catheter shown
in FIG. 6A;
[0030] FIG. 7A shows a partial perspective and cross-sectional view
of a variation of the second alternate embodiment of the catheter
shown in FIG. 6A;
[0031] FIG. 7B shows a view of the distal end of the embodiment of
the catheter shown in FIG. 7A;
[0032] FIG. 8A shows a partial perspective and cross-sectional view
of a third alternate embodiment of a catheter in accordance with
the principles of the present invention;
[0033] FIG. 8B shows a view of the distal end of the catheter shown
in FIG. 8A;
[0034] FIG. 8C shows a view of the distal end of the catheter shown
in FIG. 8A having an alternatively shaped secondary port;,
[0035] FIG. 9A shows partial perspective and cross-sectional view
of a fourth alternate embodiment of a catheter in accordance with
the principles of the present invention; and
[0036] FIG. 9B shows a view of the distal end of the catheter shown
in FIG. 9A.
[0037] FIG. 10 is a partial schematic view of an embodiment of an
underfluid catheter system in accordance with the principles of the
present invention.
[0038] FIG. 11 is an enlarged view illustrating the catheter system
operated underfluid with an aid of a volumetric field of view.
[0039] FIG. 12 is an enlarged perspective view illustrating the
catheter system providing a volumetric field of view.
[0040] FIG. 13 is an enlarged perspective view of an ultrasonic
transducer array having a single row of crystals covered by a lens
which provides a volumetric field of view.
[0041] FIG. 14 is an enlarged perspective view of an alternative
ultrasonic transducer array having multiple rows of crystals which
provides a volumetric field of view.
[0042] FIG. 15 is an enlarged perspective view of a second
alternative ultrasonic transducer array having equal number of rows
and columns of crystals which provides a volumetric field of
view.
[0043] FIG. 16 is an enlarged schematic cross-sectional view of a
concave silicone rubber lens being placed on the ultrasonic
transducer array, providing an outwardly defocused ultrasound
beam.
[0044] FIG. 17 is an enlarged schematic cross-sectional view of a
convex plastic lens being placed on the ultrasonic transducer
array, providing an outwardly defocused ultrasound beam.
[0045] FIG. 18 is an enlarged schematic cross-sectional view of a
convex silicone rubber lens being placed on the ultrasonic
transducer array, providing an inwardly focused ultrasound
beam.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] Referring now to FIG. 1-3, there is, generally illustrated
by reference numeral 20, a catheter in accordance with the
principles of the present invention. As shown, catheter 20 includes
an elongated flexible or rigid tubular catheter body 22 having a
proximal end 24 and a distal end 26. Catheter 20 includes proximate
its longitudinal distal end 26 a phased array ultrasonic transducer
30 which is used to transmit ultrasound and receive resultant
echoes so as to provide a field of view within which Doppler flow
rates can be measured and features imaged. It is appreciated that
the other types of ultrasonic transducers can be used in the
present invention, such as any mechanical types, or any dynamic
array types, or any offset stereoscopic imaging types, or any
multidimensional imaging types incorporated into a virtual reality
environment for underblood operation, etc. An electrical conductor
is disposed in the catheter body 22 for electrically connecting
transducer 30 to control circuitry 34 external of catheter body 22.
An access port 40 is disposed in catheter body 22 and extends from
proximate the proximal end 24 of catheter body 22 to proximate the
distal end 26 of catheter body 22. Access port 40 is configured to
receive a therapeutic device, such as a catheter, medication,
sensors, etc., so as to enable such items to be delivered via
access port 40 to distal end 26 of catheter body 22 for operation
within the ultrasonic transducer field of view. Such items might be
used for intervention; e.g., ablation catheter, surgical device,
etc., monitoring blood pressure, sampling blood, etc. A guide wire
access port 42 is also disposed within catheter body 22 and extends
from proximate proximal end 24 of the catheter body 22 to proximate
distal end 26 of catheter body 22 for receiving a guide wire
44.
[0047] In the preferred embodiment of the present invention, the
ultrasonic transducer preferably has a frequency of 5 to 30
megahertz (MHz) and more preferably a frequency of 7 to 10 MHz.
Intracardiac imaging in an adult will require image penetration of
up to 2 to 10 centimeters (cm) In the preferred embodiment,
catheter body 22 preferably has a diameter of 4 to 24 French (one
French divided by Pi equals one millimeter (mm)) and, more
preferably, a diameter of 6 to 12 French. In the preferred
embodiment, access port 40 has a diameter of 7 to 8 French and
guide wire port 42 has a diameter of 0.025 to 0.038 inches.
[0048] As generally illustrated in FIG. 3, catheter 20 of the
present invention can be utilized in a medical system including the
appropriate control circuitry 34 for controlling operation of the
ultrasonic transducer. As illustrated in FIG. 3, control circuitry
34 is electrically interconnected to transceiver circuitry 35
(T-/R) for receiving and transmitting signals via a cable 36 to
ultrasonic transducer 30. In turn, transceiver circuitry 35 is
electrically interconnected to Doppler circuitry 37 and an
appropriate display device 38 for displaying hemodynamics or blood
flow. In addition, transceiver circuitry 35 is electrically
interconnected to suitable imaging circuitry 39 which is
interconnected to a display 41 for displaying images.
[0049] During operation, control circuitry 34 might be designed to
cause ultrasonic transducer 30 to vibrate so as to cause an
appropriate ultrasound wave to project from proximate the distal
end 26 of catheter body 22. The ultrasound wave, represented by
lines 50 in FIG. 2, will propagate through the blood surrounding
distal end 26 and a portion of the body structure. A portion of the
ultrasound wave so transmitted will be reflected back from both the
moving red blood cells and the like and the body structures to
impinge upon transducer 30. An electrical signal is thereby
generated and transmitted by the cable 36 to the input of
transceiver 35. A signal might then be transmitted to Doppler
circuitry 37 which will include conventional amplifying and
filtering circuitry commonly used in Doppler flow metering
equipment. Doppler circuitry 37 will analyze the Doppler shift
between the transmitted frequency and the receive frequency to
thereby derive an output proportional to flow rate. This output may
then be conveniently displayed at display 38 which might be a
conventional display terminal. Accordingly, the user will be able
to obtain a readout of blood flow rates or hemodynamic
information.
[0050] In order to obtain imaging information, control circuitry 34
will likewise trigger ultrasonic transducer 30 via transceiver 35
to vibrate and produce an ultrasound wave. Once again, a portion of
the wave or energy will be reflected back to ultrasonic transducer
30 by the body features. A corresponding signal will then be sent
by cable 36 to transceiver circuitry 35. A corresponding signal is
then sent to the imaging circuitry 39 which will analyze the
incoming signal to provide, at display 41, which also might be a
conventional display apparatus, an image of the body features.
[0051] This imaging can occur while a therapeutic or surgical
device is being used at distal end 26 of catheter 20 within the
field of view provided by ultrasonic transducer 30. Accordingly,
the user will be able to monitor his/her actions and the result
thereof.
[0052] As illustrated in FIG. 3, catheter body 22 might include
proximate its proximal end 24 a suitable mounting structure 52 to
the access port 40. A therapeutic or surgical device structure 53
might be suitably attached to structure 52 by suitable means, e.g.,
threaded, etc. As illustrated, an elongated cable-like member 54
will extend along access port 40 and slightly beyond distal end 26
of catheter body 22 wherein an operative portion 56 of the surgical
tool might be interconnected.
[0053] Additional detail of distal end 26 of catheter body 22 is
illustrated in FIGS. 2, 4A, and 4B. As illustrated in FIGS. 2, 4A,
and 4B, ultrasonic transducer 30 might include a piezoelectric
polymer, such as Polyvinylidenedifloride (PVDF) 60, which is bonded
by an epoxy layer 62 to a depression 64 approximate distal end 26.
Although some detail is provided with respect to an embodiment of
an ultrasonic transducer which might be used, it will be
appreciated that various types of transducers having various
configurations and orientations might be utilized in keeping with
the present invention.
[0054] As illustrated in FIGS. 4A and 4B, the operational portion
56 of the therapeutic device is illustrated as generally being
capable of operation in the field of view of ultrasonic transducer
30. Accordingly, it is possible for the user to monitor operation
of the therapeutic device by use of the ultrasonic transducer.
Moreover, it is possible for the user to monitor the features of
the body within the field of view before, during and after
interventional activity. It is appreciated that the other types of
ultrasonic transducers can be used in the present invention, such
as any mechanical types, or any dynamic array types, or any offset
stereoscopic imaging types, or any multidimensional imaging types
incorporated into a virtual reality environment for underblood
operation, etc., so that all forms of field of views, such as 1)
tomographic (slices), 2) stereoscopic, 3) three-dimensional, 4)
virtual reality (multidimensional) can be provided in the present
invention. In addition, it is appreciated that the orientations of
the scan array on the catheter can be include side-view, end-view,
multiview (two or more views that are moveable or imminently
directional transducer referred to in the literature as
"omnidirectional"), etc.
[0055] FIG. 5A shows a partial cross-sectional view of a first
alternative embodiment 70 of the catheter apparatus. The catheter
apparatus has an elongated flexible or rigid body 72 having a
longitudinal axis and a proximal end 74 and a distal end 76.
Disposed proximate a second side of body 72 is a port 78 extending
through body 72 from proximate proximal end 74 to proximate distal
end 76 of body 72. Port 78 is for receiving and delivering to
distal end 76 of body 72 a working tool 84. Working tool 84 shown
in the Figures is illustrative only, others types of tools now
known or later developed may also be delivered to distal end 76
through port 78. Proximate a first side of body 72 is a guide wire
port 80 extending through body 72 from proximate proximal end 74 to
proximate distal end 76. Shown in guide port 80 is a guide wire
86.
[0056] Distal end 76 is disposed at an oblique angle to the
longitudinal axis of body 72, the first side of body 72 extending
further in the direction of the distal end than the second side of
body 72. An ultrasonic transducer 82, having a first side and a
second side, is disposed at an oblique angle to the longitudinal
axis of body 72 approximately corresponding to the oblique angle of
distal end 76 of body 72. The first side of ultrasonic transducer
82 is disposed proximate the first side of body 72 and the second
side of transducer 82 is disposed proximate the second side of body
72. Extending from transducer 82 to proximate proximal end 74 of
body 72 is an electrical conductor 83 connecting transducer 82 to
control circuitry external of catheter 70, as described with
respect to catheter 20 above. Having transducer 82 disposed on an
oblique angle toward port 78 allows for easy visualization of
tools, such as tool 84, extending beyond distal end 76 of body
72.
[0057] FIG. 5B shows a view of distal end 76 of body 72, showing
guide wire port means 80, transducer 82, and port means 78.
[0058] FIG. 6A shows a partial cross-sectional view of a second
alternative embodiment of the catheter in accordance with the
present invention, generally referred to as 88. Like first
alternative embodiment 70, catheter 88 has an elongated flexible or
rigid body 90 having a proximal end 92 and a distal end 94.
Catheter 88 also has a port 96 extending through body 90 from
proximate proximal end 92 to proximate distal end 94. Port 96 has a
distal end 97 proximal distal end 94 of body 90. Distal end 97 of
port 96 exits body 90 at an acute angle to a first side of body 90
toward distal end 94. Port 96 is for receiving and delivering to
distal end 94 a working tool, such as working tool 84. Catheter 88
also has a guide wire port 98 extending through body 90 from
proximate proximal end 92 to proximate distal end 94. Guide wire
port 98 is for receiving a guide wire 86.
[0059] Also shown in FIG. 6A is a transducer 100 disposed to a
first side of body 90 between distal end 94 and distal end 97 of
port 96. Extending from transducer 100 to proximate proximal end 92
of body 90 is an electrical conductor 102 disposed in the catheter
body 90 for electrically connecting transducer 100 to control
circuitry external of the catheter. With transducer 100 disposed to
the first side of body 90 and distal end 97 of port 96 exiting body
90 at an acute angle relative to the first side of body 90 toward
distal end 94, working tools extending from distal end 97 of port
96 will be within the field of view of transducer 100.
[0060] FIG. 6B shows a view of distal end 94 of catheter 88, as
shown in FIG. 6A.
[0061] FIG. 7A shows second alternative embodiment 104, as shown in
FIG. 6A, except instead of having a guide wire port 98, this
variation of the second alternative embodiment 104 has a deflection
wire guidance system 106 for manipulating distal end 94. FIG. 7B
shows a view of distal end 94 of the catheter shown in FIG. 7A.
[0062] FIG. 8A shows a third alternative embodiment 110 of the
catheter in accordance with the present invention. Third
alternative embodiment 110 has a body 112 having a distal end 114
and proximal end. Disposed proximate a first side of body 112 is a
primary port 118 extending through body 112 from proximate proximal
end 116 to proximate distal end 114. Primary port 118 has a distal
end 119 proximate distal end 114 of body 112. Oppositely disposed
from primary port 118, proximate a second side of body 112 is a
secondary port 120 extending through body 112 from proximate
proximal end 116 to proximate distal end 114. Secondary port 120
has a distal end 121 proximate distal end 114 of body 112.
[0063] Mounted proximate distal end 114 of body 112 is a transducer
122. Extending from transducer 122 through body 112 to proximate
proximal end is an electrical conductor for electrically connecting
the transducer 122 to control circuitry external of the catheter.
Transducer 122 is disposed between distal ends of primary and
secondary ports 119 and 121, respectively. With working ports 118
and 120 oppositely disposed on either side of transducer 122, it is
possible to conduct two simultaneous applications, such as holding
an object with a first tool disposed through one port and operating
on the object held by the first tool with a second tool disposed
through the other port. A typical working tool 123 and working tool
84 are shown disposed within ports 118 and 120.
[0064] Although the third alternative embodiment of the catheter
110 of the present invention does not include a guide wire port
means, a guide wire could be used in primary port 118 or secondary
port 120 to initially position catheter 110. Then the guide wire
could be retracted from port 118 or 120 and a working tool
introduced. FIG. 8B shows a view of distal end 114 of catheter
110.
[0065] FIG. 8C shows a view of a distal end 124 of a catheter 126
substantially like catheter 110 shown in FIG. 8A and FIG. 8B,
except that catheter 126 has a primary port 128 having an arc-like
shaped cross-section, rather than a circular shaped cross-section.
Although a circular cross-section has been shown in the Figures for
the various ports described herein, the size and shape of the ports
can be varied without departing from the principals of the present
invention.
[0066] FIG. 9A shows a fourth alternative embodiment of a catheter
130 of the present invention. Catheter 130 is similar to catheter
70 shown in FIG. 5A and FIG. 5B except that a plurality of ports
132 are disposed proximate a second side of flexible body 131,
rather than one port 78, as shown in FIG. 5A. With a plurality of
ports, it is possible, for example, to use a therapeutic tool
through one port while simultaneously suctioning and removing
debris through another port; or a therapeutic tool can be used
through one port while simultaneously electrophysiologically
monitoring, suctioning and/or biopsying through a second port,
third or fourth port.
[0067] The use of the catheter of the present invention is
described with respect to the preferred embodiment 20. It is
understood that the use of alternative embodiments 70, 88, 110, 126
and 130 is analogous. In use, the user would insert flexible
catheter body 22 into the body via the appropriate vascular access
to the desired location in the body, such as selected venous
locations, heart chamber, etc. In one approach, a guide wire might
be first inserted into place and then the catheter body fed along
the guide wire. The user might then insert a surgical device into
the body through access port 40 and feed the surgical device to
proximate distal end 26 of catheter body 22. Prior to, during and
after operation of the surgical device, the user might obtain both
hemodynamic measurements and images from the ultrasonic transducer
field of view. By operation of the surgical device within the field
of view of transducer, the user can monitor operation of the
surgical device at all times.
I. DETAILED FEATURES OF THE DISCLOSED CATHETERS
[0068] A. Frequency Agility Ultrasound Frequency
[0069] Frequency agility refers to the ability of a transducer to
send and receive at various frequencies, most commonly 3, 5, and 7
MHz. It is also appreciated that a single frequency from a single
transducer device can be sent and received. In general, higher
frequencies are used to image fine detail of more proximal or
closely related objects while lower frequency transducers scan more
remote objects with less detail. The proposed device optimally uses
a 5 to 20 mHz transducer with the most optimally applied frequency
of 7 to 10 mHz. The lower frequency used in the UIHC reflects the
need to image larger objects such as the cardiac septa, valves, and
extravascular anatomy.
[0070] B. Catheter size
[0071] Catheter diameters will generally be larger than
intravascular catheters and will range 4 to 24 French with the
optimal catheter diameter 6 to 12 French (French size=French
divided by Pi plus millimeter diameter).
[0072] C. Intervention
[0073] One primary function of this catheter system is to guide the
logical and safe use of various a) ablation, b) laser, c) cutting,
occluding, e) etc., catheter-based interventional tools. The
invention has the access port through which other technologies
(devices) can be passed. Once the interventional tool exits the
catheter tip, it can be directed repeatedly and selectively to
specific site for controlled intervention.
[0074] D. Imaging
[0075] The invention is also an imaging system capable of
visualizing intracardiac, intravascular, and extravascular
structures. Because the transducer frequencies utilized are usually
lower than intravascular systems, the catheter 20 can see multiple
cardiac cavities and visualize structures outside the vascular
system. The imaging capability is basically two-fold: 1) diagnostic
and 2) application.
[0076] 1. Diagnostic imaging: The catheter 20 can effectively
perform diagnostic intracardiac and transvascular imaging. This
application will more than likely be performed just prior to an
interventional application. The intervention then will follow using
the same catheter system and its unique delivery capability. Some
examples of diagnostic imaging include 1) accurate visualization
and measurement of an intracardiac defect, 2) characterization of
valve orifice, 3) localization of a tumor and its connections, 4)
etc. Extravascular diagnoses would include 1) visualize pancreatic
mass/pathology, 2) retroperitoneal pathology, 3) intracranial
imaging, 4) recognition of perivascular pathology, and 5) imaging
of other fluid containing space such as urinary bladder, bile
system, fluid filled orifice or cavity (e.g. filled saline),
etc.
[0077] 2. Application imaging refers to the use of the catheter and
its imaging capability to deliver and then apply another technology
such as 1) occlusion device for closure of a septal defect, 2)
ablation catheters for treatment of bypass tracts, 3) creation of a
defect such as that with the blade septostomy catheter or
laser-based catheter system, and 4) directing of valvuloplasty
(such as prostrate surgery, placement of stents, gallstone removal
etc.), etc. By direct imaging of an application, such as ablation,
the procedure will be able to be performed more safely and
repeatedly, and the result can be better assessed.
[0078] E. Hemodynamics
[0079] The catheter 20 is a truly combined ultrasound Doppler and
conventional hemodynamic catheter. There are Doppler catheters, and
there are catheters capable of imaging and measuring hemodynamic
pressure. However, the catheter 20 is capable of Doppler
hemodynamics (continuous and pulsed wave Doppler) as well as
high-fidelity hemodynamic pressure recording while simultaneously
imaging the heart and blood vessel. The catheter 20 provides a
combination of imaging, hemodynamic, and interventional delivery
catheter.
II. ANALOGY WITH OTHER EXISTING THERAPEUTIC TECHNOLOGIES
[0080] Like interventional peritoneoscopy, intracardiac ultrasound
is capable of 1) imaging, 2) delivering a therapeutic device, and
3) obtaining simultaneous hemodynamics which can be used to develop
less invasive cardiac surgical techniques. This simultaneous use of
one or more devices within the heart or vascular tree opens up the
potential to develop less invasive surgical therapies. Examples
would include 1) removal of a cardiac tumor by visually grasping
the tumor with one device and visually cutting its attachment with
a second device, thus allowing less invasive extraction of
intracardiac mass lesions, 2) visually placing an
electrophysiologic catheter on a bypass tract and then with direct
ultrasound visualization ablate the underlying tract with the
second device, 3) visually performing laser surgery such as
creating an intra-atrial defect, vaporization of obstructing
thrombus such as is seen in pseudointimal occlusion of conduits, 4)
visually removing a foreign body from the heart or vascular tree,
and 5) directing intravascular surgery from within a blood vessel
or monitoring concomitant hemodynamic changes.
III. SELECTED APPLICATIONS INCLUDE THE FOLLOWING
[0081] A. Radio-frequency Ablation
[0082] Presently a bypass tract is localized by an
electrophysiologic study which systematically maps the
atrioventricular valve annulus. Positioning of the ablation
catheter is determined by x-ray fluoroscopy and certain electrical
measurements which relate the distance of the ablation catheter
from a reference catheter. The catheter 20 will allow an operator
to map the atrioventricular valve under direct ultrasound
visualization. Thus, increased accuracy of catheter placement,
precision of the applied therapy, and immediate assessment of
outcome would result.
[0083] The above ablation technique would be particularly
applicable for right-sided bypass tracts (in and around the
tricuspid valve annulus). This would be accomplished by placement
of the catheter 20 through the superior vena cava above the
tricuspid annulus.
[0084] For left-sided bypass tracts, the catheter 20 could be
placed across the atrial septum under direct ultrasound
visualization. The mitral annulus could thus be mapped directly and
the localized bypass tract precisely ablated under visual
ultrasonic and hemodynamic direction. Complications such as valve
perforation, multiple imprecise applications of ablation energy,
and inadvertent ablation of normal conduction tissue would be
substantially reduced.
[0085] Ablation of bypass tracts would be an ideal utilization of
the proposed ultrasonic interventional catheter system.
[0086] B. Cardiac biopsy
[0087] In the era of safe cardiac biopsy, there is a need for
precision biopsy. Ultrasound direction of the biopsy device to an
intracardiac tumor, avoidance of scar, and selective biopsy of
suspect tissue are feasible with the catheter 20 device. One of the
more frequently life-threatening complications in the cardiac
catheterization laboratory is catheter perforation of the heart.
Such complications most commonly accompany cardiac biopsy,
electrophysiologic catheter manipulation, and valvuloplasty. Use of
an intracardiac ultrasound imaging, hemodynamics, and delivery
catheter should substantially increase or improve safety of these
procedures.
[0088] C. Transvascular diagnoses
[0089] The catheter 20 will allow visualization of perivascular and
extravascular pathology. Transvascular or transorgan imaging and
localization of pathology out of the immediate vascular tree will
result in a substantial step forward in the diagnosis and possible
treatment of difficult to reach pathology. The catheter 20 cannot
only diagnose but guide a biopsy needle and therapeutic device to
an extravascular lesion in question. The retroperitoneum,
mediastinum, and basal cerebrovascular pathology are logical areas
of interest. Accurate characterization of various pathologies will
be more feasible. Every organ has its own vascular system, and the
proposed ultrasound transvascular system is an ideal tool to assess
difficult to reach areas of the body. The vascular system is a
conduit to each organ, and the catheter 20 can be delivered to each
organ. Characterization of the underlying parenchyma and possible
transvascular biopsy or treatment will ultimately be developed.
[0090] D. Ultrasound Manipulation of Therapeutic Devices Within the
Heart and Blood Vessels
[0091] The catheter 20 opens the potential not only to visualize
but to directly intervene with the same catheter system. There are
numerous intraoperative catheter-based systems which to date use
conventional x-ray to accomplish their goal of placement and
application of a specified therapy. There is a need for a device
which can more precisely guide such catheter-based systems. It is
too expensive and technically impractical to incorporate ultrasound
into every catheter based technology. The catheter 20 has all the
prerequisites of an ideal imaging and interventional instrument and
has the ability to 1) image, 2) obtain hemodynamics by multiple
means (pressure dynamics and Doppler), 3) function as a diagnostic
as well as therapeutic device, and 4) accommodate other unique
technologies which would enhance the application of both
systems.
[0092] E. General Applications
[0093] It is anticipated that intravascular, transvascular, and
intracardiac devices could be delivered through the port means
described above within or about the heart and blood vessels of the
body. The catheters described above, however, could also be used in
any ectogenic tissue, such as liver, parenchyma, bile ducts,
ureters, urinary bladder, and intracranial--i.e., any place in the
body which is echogenic which would allow passage of a catheter for
either diagnostic or therapeutic applications using ultrasound
visualization.
[0094] F. Expanding Applications of Technologies
[0095] The catheter 20 is a new and exciting innovation to invasive
medicine. There are multiple other and yet-to-be-determined
applications. However, the new concept described opens the
potential development of less expensive, more precise, and safe
intravascular and transvascular diagnostic and surgical
devices.
IV. SUMMARY
[0096] The catheter 20 is very much different from any conventional
ultrasound catheter-based system. The catheter 20 incorporates
image and hemodynamic capability as well as the ability to deliver
other diverse technologies to specified sites within the
cardiovascular system (heart and blood vessels). The catheter 20 is
seen as an ideal diagnostic and therapeutic tool for future
development. The proposed applications foster greater preciseness,
adaptability, and safety. Ultrasound permits visualization from
within blood-filled spaces as well as through blood-filled spaces
into other water- or fluid-filled tissue. The catheter 20 will
evolve into the ultimate interventional system.
[0097] FIG. 4A is an illustration showing one potential use of the
ultrasound imaging and hemodynamic catheter (UIHC). In this
particular example, the UIHC is advanced from the superior vena
cava to the tricuspid valve annulus. Simultaneously visualized in
the annulus, electrophysiologic and ultimately and ablation
procedure are performed. The ability to directly visualize and
direct therapeutic catheter devices highlights only one of the many
applications of the UIHC.
[0098] Another embodiment of the catheter system, generally in
accordance with the principles of the present invention is shown in
FIG. 10, which is designated as reference numeral 200. The catheter
system 200 has a catheter body 202 and an ultrasonic transducer
array 204 mounted on proximate the distal end of the catheter body
202. It is appreciated that other parts of the catheter system can
be similar to those in the catheter systems 20, 70, 88, 104, 110,
and 130 as shown in FIGS. 1, 5A, 6A, 7A, 8A, and 9A, respectively.
For the purpose of illustration and explanation, FIG. 10 shows a
partial schematic view of the catheter system 200.
[0099] In FIG. 11, the catheter body 202 of the catheter system 200
is inserted into an underfluid cavity of a body 206. In FIG. 12, a
therapeutic device 208 projects from the catheter system 200
proximate the distal end of the catheter system 200 and manipulates
features in the cavity of the body 208. This manipulation is under
observation of a 3-dimensional image shown on a display, which can
be similarly connected to the ultrasound transducer array as shown
in FIG. 3, outside the body 208 proximate the proximal end of the
catheter system 200.
[0100] Likewise, the underfluid catheter body 202 has tool port 210
disposed in the catheter body 202 extending from proximate the
proximal end to proximate the distal end of the catheter body 202
for receiving the therapeutic device 208, such as a catheter,
medication, sensor, surgical device, etc., so as to enable such
items to be delivered via the tool port to proximate the distal end
of the catheter body 202. It will be appreciated that the tool port
is optional. It will also be appreciated that additional tool ports
can be disposed in the catheter body 202. The therapeutic device
208 is projected into an underfluid environment, as shown in FIGS.
11-12, and operated therein with the aid of a volumetric
3-dimensional image of the underfluid environment and the
therapeutic device 208.
[0101] Further, the catheter system 200 can also optionally include
a guidewire port 212 disposed in the catheter body 202 extending
from proximate the proximal end to proximate the distal end of the
catheter body 202 for receiving a guide wire 214. The guide wire
214 guides the catheter body 202 when inserting into a body, such
as the body 206.
[0102] Further, the catheter system 200 includes a control circuit
which can be similar to the control circuitry 34 shown in FIG. 3.
The control circuitry 34 is used to control the operation of the
ultrasonic transducer array 204. The control circuitry 34 is
electrically interconnected to a transceiver circuitry 35 (T/R) for
receiving and transmitting signals via a cable 36 to ultrasonic
transducer array 204. In turn, the transceiver circuitry 35 is
electrically interconnected to a measuring circuitry, such as the
Doppler circuitry 37, which is interconnected to a first display 38
for displaying hemodynamics, blood flow, etc. In addition, the
transceiver circuitry 35 is electrically interconnected to an
imaging circuitry 39 which is interconnected to a second display 41
for displaying a 3-dimensional image of the underfluid
environment.
[0103] As shown in FIG. 10, the catheter body 202 can also house
some encased electronics 216.
[0104] In the preferred embodiment of the present invention, the
ultrasonic transducer array 204 is mounted on a side of the
catheter body 202. The array 204 can also be mounted on the tip of
the catheter body 202. The catheter body 202 is a flexible catheter
capable of manual or electronic interactive flexible tip. The
guidewire port 212 has a diameter of 0.035 inches. It is
appreciated that the range of the diameter of the guidewire port
212 can be varied from 0.025 to 0.038 inches. The tool port 210 for
transporting the therapeutic device 208 is a 7 French port. It is
appreciated that the range of the tool port 210 can be varied from
3 French to 20 French.
[0105] As shown in FIG. 13, the ultrasonic transducer array 204 is
comprised of a single row of individual crystals 218. Each crystal
218 is arranged side by side. A field of view generated by the
ultrasonic transducer array 204 has a primary tomographic plane 220
in azimuthal dimension along an AZ axis. The row of the array 204
is parallel to the AZ axis. An elevation axis (EL) is perpendicular
to the AZ axis. A primary beam from the ultrasonic transducer array
204 lies in the primary tomographic plane 220. The primary beam has
usually a sector configuration (generally a fan or triangle shape)
or a linear configuration (generally rectangular shape).
[0106] The volumetric field of view can be produced by defocusing
the primary tomographic plane 220 such that a plurality of
elevation planes 222 spread laterally outward from the primary
tomographic plane 220. The primary tomographic plane 220 and the
elevation planes 222 together form a volumetric field of view. To
defocus the primary tomographic plane 220 as shown in FIG. 13, a
lens 224 is placed on the top of the ultrasonic transducer array
204. The ultrasound beams which are usually collimated are
defocused along the elevation direction (EL) after the beams go
through the lens 224 (or other lenses 226, 228 as shown in FIGS. 16
and 17).
[0107] The lenses 224, 226, or 228 are preferred to be made from
materials such as a plastic material or silicone rubber. It is
appreciated that other types materials can be used to make the
lens.
[0108] In FIG. 16, the lens 226 is a concave lens, preferably made
of silicone rubber, which transmits ultrasound waves slower than
the surrounding environment, such as body tissues. The ultrasound
waves pass through the lens 226 and then impact on the body
tissues. The speed of the ultrasound waves is slower in the lens
but faster in tissue (e.g. 1,540 m/sec). Accordingly, the
transmitted ultrasound waves, after passing through more slowly
transmitted lens 226 and striking faster transmitted body tissues,
will be directed outward. As a result, the collimated ultrasound
beams are defocused in the elevation dimension.
[0109] The defocusing can also be achieved by placing a convex lens
228 on the ultrasonic transducer array as shown in FIG. 17. The
convex lens 228, preferably made of plastic, transmits ultrasound
waves faster than the surrounding environment, such as body
tissues. The ultrasound waves pass through the convex lens 228 and
then impact on the body tissues. The ultrasound beams are pulled
outward due to the faster velocity in the convex lens 228. As a
result, the ultrasound beams are defocused in the elevation
dimension.
[0110] FIG. 18, on the other hand, demonstrates a way of using a
lens 230 to, in fact, focus the beams from the transducer array.
The collimated ultrasound beams are generated from the ultrasonic
transducer array. The convex lens 230 transmits ultrasound waves
slower than the surrounding environment, such as body tissues, do.
Accordingly, the ultrasound beams are pulled inward due to the
faster velocity in body tissues. As a result, the ultrasound beams
are focused toward the primary tomographic plane 220.
[0111] FIG. 14 shows an alternative embodiment of ultrasonic
transducer array 204' which is comprised of multiple rows of
individual piezoelectric crystals 218. The rows of the array 204'
are parallel to the AZ axis. The columns of the array 204' are
parallel to the elevation dimension along the EL axis, which is
perpendicular to AZ axis. This type of array is also called
volumetric one and one-half (1 and {fraction (1/2)}) dimensional
array. The "elevation" image and the ultimate 3-dimensional image
are the result of phasing the crystals in the elevation direction
as well as in the azimuthal direction.
[0112] FIG. 15 shows a second alternative embodiment of ultrasonic
transducer array 204" which is comprised of equal number of
crystals 218 in all dimensions. Similar to the one and one-half (1
and 1/2) dimensional array 204' , the rows of the array 204" are
parallel to the AZ axis, and the columns of the array 204" are
parallel to the EL axis. This type of array is also called a two
(2) dimensional array. The "elevation" image and the ultimate
3-dimensional image are the result of phasing the crystals in the
EL direction as well as the AZ direction.
[0113] Accordingly, the volumetric field of view as shown in FIGS.
14-15 provides 3-dimensional images of structures under
observation. Further, the volumetric field of view not only shows,
for example, a primary tomographic cut, but also volumes of
features, such as tissue.
[0114] In the embodiments of FIGS. 14 and 15, it will be
appreciated that no lens is required to generate a volumetric
image. Consequently, the ultrasonic beams are focused in both the
azimuthal and elevational directions. The volumetric image is
generated because the arrays of FIGS. 14 and 15 are 2 dimensional.
As a result, a volumetric image can be generated by electronically
phasing and steering the ultrasonic impulses in both the azimuthal
and the elevational directions.
[0115] In the preferred embodiment, the ultrasound transducer is a
7-10 MHz sector array transducer. It is appreciated that the range
of the sector array transducer can be varied from 3.7 MHz to 30
MHz.
[0116] It is also appreciated that the lenses 224, 226, 228, 230
can be made of different materials which will have variable effects
on the transmitted ultrasound beams. By using such defocusing lens,
a 3-dimensional image can be seen on a 2-dimensional display
outside the body 206 in a real-time operation. Elevation defocusing
in using a lens does not interfere with the inherent frame rate or
adversely affect conventional echo data.
[0117] The lens can also be fabricated to reduce the strength of
the dominant tomographic plane (AZ plane). One means of
accomplishing this is by changing the attenuation characteristics
of the lens so as to reduce the tomographic effect and enhance the
volumetric effect of the insonated and displayed object.
[0118] The lens is optional, for example, as shown in FIGS. 14 and
15 whereby the beams are phased in both the azimuthal and
elevational planes.
[0119] The present invention has numerous clinical applications.
One of which is the underfluid imaging when imaging from within
chambers, cavities or blood vessels. Since the physical space is
small, and the anatomy in question is closely approximated and
usually totally surrounds the transducer, a 3-dimensional imaging
is a solution to visualizing larger volumes of underfluid tissue.
In this imaging application, the defocusing lens or electronically
controlled phasing in both the azimuthal and elevational directions
(i.e., using multi-dimensional arrays such as 1-{fraction (1/2)}
dimensional or 2 dimensional arrays) produces volumetric images.
Working port(s) and guidewire(s) are optional. Further, catheter
lengths and transducer frequencies are variable.
[0120] Another application, when the working port is optionally
used in the catheter, is to intervene or manipulate an underfluid
structure, such as cutting an underfluid tissue, etc., by a
therapeutic device, such as the therapeutic devices 50, 84, 123,
208 shown in FIGS. 4B, 5A, 8A, and 12, respectively. Under such
direct volumetric visual guidance, diagnostic and therapeutic
procedures can be performed with better spatial orientation.
[0121] Another application, when the guidewire is optionally used
in the catheter, is to measure some underfluid features, such as
blood flow, etc. The measurement can also be performed under direct
volumetric visual guidance in the present invention.
[0122] Other generic applications include Doppler blood flow
determination, color flow imaging, etc.
[0123] Thus, the preferred embodiment of the present invention has
been described in detail. It is to be understood, however, that
even though numerous characteristics and advantages of the present
invention have been set forth in the foregoing description,
together with details of the structure and function of the
invention, the disclosure is illustrative only, and changes may be
made in detail, especially in matters of shape, size and
arrangement of parts within the principles of the invention to the
full extent indicated by the broad general meaning of the terms in
which the appended claims are expressed.
* * * * *