Loop imaging catheter

Details Loop imaging catheter Loop imaging catheter

2000-10-20

2002-11-19

Jaworski, Francis J. (Department: 3737)

Surgery

Diagnostic testing

Detecting nuclear, electromagnetic, or ultrasonic radiation

C600S459000

Reexamination Certificate

active

06482162

ABSTRACT:

FIELD OF THE INVENTION
The present invention pertains to medical imaging devices, and more particularly, to ultrasonic imaging catheters used in diagnostic applications.
BACKGROUND
Presently, minimally invasive imaging devices are employed in the diagnostic analysis of relatively large body cavities, such as, e.g., a heart chamber. Of particular interest to the present invention, ultrasonic imaging catheters have been employed to generate cross-sectional images from within the body cavity. The cross-sectional images reveal the surrounding contour of tissue, secondary structure, and other structural information relevant to treatment and diagnosis of various diseased conditions.
In this connection, a known imaging catheter
20
, as depicted in
FIG. 1
, includes an elongate catheter body
22
with a distally formed elongate acoustic window
24
through which ultrasonic energy transparently passes. The catheter body
22
includes an imaging lumen
26
in which a rotatably and longitudinally translatable imaging core
28
is disposed. The imaging core
28
comprises a drive cable
30
along with a distally connected ultrasonic transducer housing
32
and mounted ultrasonic transducer
34
. The transducer
34
is mechanically coupled to a drive unit (not shown) via the drive cable
30
and electrically coupled to a signal processor (not shown) via a transmission line
36
disposed in the drive cable
30
. The transmission line
36
may consist of coaxial cable, triaxial cable, twisted pair, or other suitable configurations.
Disposal of the acoustic window
24
, at a desired region within the body cavity and subsequent operation of the drive unit and signal processor, generates a longitudinal image scan of the tissue surrounding the body cavity. In particular, the electrical signals are transmitted to and received from the transducer
34
, while the transducer
34
is rotationally and longitudinally translated relative to the acoustic window
24
. In this manner, a multitude of imaging data “slices” are generated, which can be synthesized to produce a three-dimensional image of the body cavity for analysis by a viewing physician.
The ability to generate a three-dimensional image of a body cavity is advantageous in several respects. First, such an image generally allows a physician to ascertain the existence of a diseased region within the body cavity. Second, if such diseased region is found, the image permits a qualitative assessment of the nature of the disease in order to help select the most effective treatment modality. Third, the image can be used to determine the exact location of the diseased region, or the location of a therapeutic element relative to the diseased region, so that intervention can be directed only at the diseased region and not at healthy regions of the body cavity where the interventional procedure might cause damage.
Referring to
FIG. 2
, the imaging catheter
20
can be used to generate a three-dimensional image of a region of a heart
50
. In particular, the imaging catheter
20
is advanced through the vasculature of the patient until the acoustic window
24
extends into a chamber of the heart
50
, such as, e.g., the left ventricle
52
. A longitudinal scan of the heart
50
is then performed, thereby generating a multitude of cross-sectional imaging data slices along respective imaging planes, such as, e.g., representative planes P(
1
)-P(
5
). Subsequent synthesis of the imaging data slices will result in a single three-dimensional image of heart tissue
50
which is intersected by the imaging planes. Heart tissue
50
not intersected by the imaging planes, such as, e.g., at the apex
54
of the heart
50
, will not appear in the three-dimensional image. Thus, the image will not include potentially vital information that could lead to the proper diagnosis and subsequent treatment of a diseased region of the heart
50
.
As shown in
FIG. 3
, the acoustic window
38
can be manipulated inside the heart
50
, such that imaging planes of a subsequent longitudinal scan, such as, e.g., representative imaging planes P(
6
)-P(
8
), intersect heart tissue
50
not imaged during the first longitudinal scan, such as, e.g., at the apex
54
. This task may sometimes be difficult or tedious to perform, and even if apparently successful, may result in a multitude of uncorrelated three-dimensional images, making proper examination of the heart
50
more difficult.
Further, referring back to
FIG. 2
, the force that the mitral valve
56
and entrance
58
to the left atrium
60
of the heart
50
exerts on the acoustic window
24
may create an arc
38
in the acoustic window
24
through which the heart
50
is imaged. As a result, the imaging data slices which are generated along the imaging planes, such as, e.g., planes P(
4
) and (P
5
), may, when synthesized, result in a image which is distorted at the left atrium
60
and right atrium
62
, since the relative rotational orientation of the imaging planes P(
4
) and P(
5
) are unknown due to the randomness of the geometry of the arc
38
.
SUMMARY OF THE INVENTION
The present invention overcomes the afore-described drawbacks of a conventional imaging device by providing an imaging device, such as, e.g., an ultrasonic imaging catheter, that includes a pull wire connected to the distal end thereof, such that manipulation of the pull wire forms the distal end of the imaging device into a curvilinear geometry that is known and repeatable.
In a first preferred embodiment, an ultrasonic imaging catheter, according to the present invention, includes an elongate catheter body with a distally formed acoustic window. An imaging core, which includes a drive cable and a distally mounted ultrasonic transducer, is disposed in an imaging lumen of the catheter body. The transducer is disposed in the acoustic window and is rotationally and longitudinally translatable relative thereto. The pull wire is disposed within a pull wire lumen, which may be the same as the imaging lumen, of the catheter body and is connected to the distal tip of the acoustic window. Longitudinal displacement of the pull wire, relative to the catheter body, causes the acoustic window to form into a known and repeatable arc. A stiffening member can be disposed along the acoustic window to provide resilience thereto.
In a preferred imaging method, the acoustic window of the catheter is placed within a cavity of an organ, such as, e.g., the left ventricle of a heart. The acoustic window is formed into an arc, and a curvilinear longitudinal imaging scan is performed through the arc, generating a multitude of cross-sectional imaging data slices respectively along a multitude of imaging planes. Due to the curvature of the acoustic window, the imaging planes have differing relative rotational orientations, which intersect the entire body cavity, thereby providing a single three-dimensional image of virtually the entire body cavity. Since the geometry of the arc is known, any distortion caused by the curvature of the acoustic window can be removed from the three-dimensional image.
In an alternatively preferred imaging method, the imaging catheter is used in conjunction with a therapeutic catheter having a distally located therapeutic element, such as, e.g., an ablation electrode. The acoustic window of the imaging catheter and the ablation electrode of the therapeutic catheter are placed in a body cavity, such as, e.g., the left ventricle of a heart. The imaging catheter is operated, in a similar manner as described above, to obtain a three-dimensional image of the left ventricle. The image generally will include an acoustic artifact caused by the ablation electrode, which can be used to locate the ablation electrode adjacent the diseased region of the left ventricle for subsequent ablation thereof.
In still another alternatively preferred imaging method, the imaging catheter is used in conjunction with another diagnostic catheter and a therapeutic catheter. The diagnostic catheter preferably includes a distal basket structure that includes an array of electrode

Affiliated with

Also associated with

Rating

Loop imaging catheter does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Loop imaging catheter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Loop imaging catheter will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2948136