Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-05-31
2003-11-25
Manuel, George (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S473000, C600S478000, C600S407000
Reexamination Certificate
active
06654630
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to catheters and more particularly to catheter apparatus utilizing optical imaging arrangements for the sensing and analysis of tissue or particulate samples in a medium.
BACKGROUND OF THE INVENTION
Mammalian vessels are subject to damage by atherosclerotic plaque, vascular lesions, and aneurysms. Such plaque may be simple plaque or vulnerable plaque. Vulnerable plaque consists of lipid-rich core material and inflammatory cells. These vulnerable plaques are prone to rupture and erosion. Sixty to seventy percent of fatal myocardial infarctions are triggered by plaque rupture. In about twenty five to thirty percent of fatal infarctions, plaque erosion or ulceration is the triggering mechanism. Erosion occurs when the endothelium beneath the thrombus is replaced by inflammatory cells. Such inflammatory cells are commonly associated with plaque rupture and ulceration. Plaque rupture and ulceration may respond to and aggravate intimal injury, promoting thrombosis and vasoconstriction.
Vulnerable plaques, which pose a significant risk of precipitating infarction, occur in coronary arteries which may appear apparently normal or only mildly stenotic on angiograms. Thus, detection of these vulnerable plaques prior to any rupture or erosion would present a significant advance in the treatment of a mammalian patient.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to a catheter based system for the optical analysis of mammalian vessels, tissue samples and methods of utilization of that catheter based system. Such a catheter based system is utilized to independently deliver and collect optical radiation through an arrangement of optical fibers in such a manner that the radiation delivered and collected by those optical fibers is known and may be controlled.
The catheter based optical system of the present invention comprises a light source such as a laser or the like, for example a titanium sapphire laser in optical communication with an optical coupler. The catheter based optical system includes and elongated catheter having a distal end and a proximal end. The catheter comprises an outermost sheath of thin resilient material having proper columnar strength, the distal end of which is formed of polyethylene or other biocompatible material, and is optically transparent. An elongated optical delivery fiber arrangement is disposed from the proximal end of the catheter through and into the distal end thereof. An optical collection fiber arrangement is also disposed within the catheter sheath alongside the optical delivery fiber arrangement. The optical delivery fiber arrangement has a distal end which is in optical communication with an optical re-director within the distal end of the catheter sheath. The optical delivery fiber arrangement has a proximal end which is in optical communication with the optical coupler at the proximal end of the catheter shaft. The optical collection fiber arrangement has a distal end which is in optical communication with the optical re-director within the distal end of the catheter sheath. The optical collection fiber arrangement has a proximal end which is in optical communication with the optical coupler at the proximal end of the catheter sheath. The optical re-director at the distal end of the catheter sheath is arranged to re-direct light traveling through the optical delivery fiber arrangement and generally radially outwardly through the sidewall of the catheter sheath, and onto a vessel wall of a mammalian subject undergoing the test procedure.
A reflected light path receiving member may be arranged in the optical re-director a spaced distance apart from the optical delivery path within the optical re-director. The receiving member collects the reflected light from any tissue within the mammalian vessel and communicates it proximally through the optical collection fiber arrangement for transmission into the optical coupler.
A detector is in communication with the optical coupler, to receive the optical radiation from the optical collector fiber arrangement and convert that signal into an electronic display. The electronic display is presented as an analysis of the tissue structure within the vessel being examined within the mammalian host.
In a further embodiment of the present invention, a rotatable optical coupler is arranged in optical communication between the optical coupler and the proximal ends of the optical delivery fiber arrangement and the optical collection fiber arrangement. The rotatable optical coupler, in this embodiment, may be configured as an optical slip ring generally somewhat similar to those arrangements as may be seen in U.S. Pat. No. 4,109,998 to Iverson or in U.S. Pat. No. 4,725,116, to Spencer et al. or to U.S. Pat. No. 4,872,737, to Fukahori et al., each of which patents are incorporated herein by reference in their entirety. In this embodiment, both the optical delivery fiber arrangement and the optical collection fiber arrangement are each rotated simultaneously about an elongated axis of rotation which is co-axial with the longitudinal axis of the catheter sheath. In this embodiment, the optical re-director also rotates within the distal end of the catheter sheath.
The optical re-director may be comprised of right angled extensions or of diagonally arranged mirrors disposed at the distal end of each respective optical collection fiber arrangement and optical delivery fiber arrangement. The distal end of each fiber arrangement respectively emits and collects optical radiation in an independent and separate manner with respect to the inner wall of the vessel of the mammalian patient into which the catheter apparatus is being worked. The distal ends of each fiber arrangement are spaced apart from one another along the longitudinal axis of rotation of the fiber assembly. The use of independent fibers for delivering and for collecting optical radiation permits control of the separation between where the point of the optical radiation impinges upon the tissue sample of the vessel and the point where the optical radiation is collected from the tissue sample of the vessel. Such an optical fiber arrangement may be in the order of two to three microns in diameter to as much as two to three millimeters in diameter. In a further contemplative embodiment, the optical delivery fiber arrangement may be comprised of a plurality of individual elongated optical fibers which collectively comprise the optical delivery fiber arrangement. In a similar manner, the optical collection fiber arrangement may be comprised of a plurality of individual optical collection fibers.
In a further preferred embodiment of the present invention, the optical collection fiber arrangement may be of a different, i.e. a greater diameter than the optical delivery fiber arrangement to permit weaker signals to be transmitted therethrough without loss of a signal strength.
In yet a further object of the present invention, it is contemplated that the optical delivery fiber arrangement and the optical collection fiber arrangement be in a coil with respect to one another. That is, the delivery fiber arrangement may be arranged as an inner coil twisted in a one hand direction with the collection fiber arrangement disposed as an outer coil of an opposite hand direction or as a twisted pair, to provide columnar strength to the catheter sheath during its insertion within the mammalian vessel, and to provide stability while permitting the minimization of the diameter of the catheter sheath that would otherwise require wall reinforcement and reinforced guideability.
In a further embodiment of the present invention, the optical delivery fiber arrangement and the optical collection fiber arrangement may be coaxial, and separated by a reflecting or containing cladding arranged therebetween. A containing cladding may also be arranged on the outer peripheral surface of the combined delivery fiber and collection fiber arrangement arranged rotatably within the catheter sheath. Such an embodiment may include the delivery fibe
Bouma Brett
Furnish Simon M.
Griffin Mark A.
Ryan S. Eric
Tang Jing
Fish & Richardson P.C.
InfraReDx, Inc.
Manuel George
Pass Barry
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