US20030028114A1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for detecting vulnerable atherosclerotic plaque
Assignee: The University of Texas System
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Filing: 2001-12-26
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Granted: —
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Expires: 2021-12-26
Abstract
Abstract Methods and devices are disclosed for detecting vulnerable atherosclerotic plaque, or plaque at risk of reducing blood flow in a vessel, by a identifying a region of elevated temperature along a living vessel wall. The disclosure that human atherosclerotic plaque with measurable temperature heterogeneity has the morphological characteristics of plaque that is likely to ulcerate provides a new and sensitive technique for detecting and treating these dangerous plaques before myocardial infarction and its consequences occur. The disclosed methods are advantageous over conventional plaque detection techniques because they are capable of differentiating between those plaques that are at great risk of rupture, fissure, or ulceration, and consequent thrombosis and occlusion of the artery and those that are not presently at risk. Infrared heat-sensing catheters useful for identifying potentially fatal arterial plaques in patients with disease of the coronary or other arteries are also described. In some embodiments a coherent infrared fiber optic bundle is employed to radially and longitudinally explore a luminal wall to identify inflamed, heat-producing, atherosclerotic plaque. Certain other methods and devices are disclosed which are particularly suited for non-invasively identifying and then monitoring the progression or amelioration of an inflamed plaque in a patient, and for monitoring for onset of inflammation in an implanted arteriovenous graft. Also disclosed are thermocouple basket catheters and thermistor basket catheters which are also capable of detecting temperature heterogeneity along a vessel wall.
Inventors
- 👤 S. Casscells
- 👤 James Willerson
- 👤 Morteza Naghavi
- 👤 Bujin Guo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:06
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/68; A61B5/6846; A61B5/6885; A61B5/0059; A61B5/0077; A61B5/0082; A61B5/0084; A61B5/0086; A61B5/01; A61B5/015; A61B5/02; A61B5/02007; A61B5/05; A61B5/0507; A61B5/41; A61B5/414; A61B5/415; A61B5/418; A61B5/6847; A61B5/6852; A61B5/6853; A61B5/6858; A61B8/00; A61B8/52; A61B8/5215; A61B8/5238; A61B17/00; A61B2017/00017; A61B2017/00022; A61B2017/00084; A61B17/22; A61B2017/22001; A61B2560/00; A61B2560/02; A61B2560/0223; A61B5/0071; A61B5/0075; A61B5/413; A61B8/12; A61B8/44; A61B8/4444; A61B8/445; A61B8/5223
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
49 words
1 . A method of detecting along a vessel wall an atherosclerotic plaque at risk of reducing fluid flow within said vessel, the method comprising determining whether said plaque or a region thereof exhibits an elevated temperature compared to the temperature of at least one adjacent vessel wall site.
Claim 2
Dependent Claim
49 words
1 . A method of detecting along a vessel wall an atherosclerotic plaque at risk of reducing fluid flow within said vessel, the method comprising determining whether said plaque or a region thereof exhibits an elevated temperature compared to the temperature of at least one adjacent vessel wall site.
Claim 3
Dependent Claim
63 words
2 . A method of identifying an atherosclerotic plaque at risk of rupture or thrombosis in a living vessel, the method comprising measuring the temperature of at least two sites along the lumen wall of said vessel and detecting a temperature elevation of about 0.4 to 4° C. at one said site compared to the temperature of at least one other said site.
Claim 4
Dependent Claim
63 words
2 . A method of identifying an atherosclerotic plaque at risk of rupture or thrombosis in a living vessel, the method comprising measuring the temperature of at least two sites along the lumen wall of said vessel and detecting a temperature elevation of about 0.4 to 4° C. at one said site compared to the temperature of at least one other said site.
Claim 5
Dependent Claim
38 words
3 . The method of claim 1 or 2 further comprising determining average vessel wall temperature and measuring a temperature difference of about 0.4 to 4° C. between at least one vessel wall site and said average temperature.
Claim 6
Dependent Claim
33 words
4 . The method of claim 3 wherein said measuring comprises measuring a temperature difference of at least about 1.5° C. between at least one said site and said average vessel wall temperature.
Claim 7
Dependent Claim
20 words
5 . The method of claim 1 or 2 further comprising obtaining an intravascular ultrasound image of said atherosclerotic plaque.
Claim 8
Dependent Claim
23 words
6 . The method of claim 1 or 2 further comprising introducing a heat detecting catheter into a vessel of a living subject.
Claim 9
Dependent Claim
61 words
7 . The method of claim 6 wherein said step of introducing a heat detecting catheter comprises: inserting an infrared imaging catheter into said vessel, said infrared imaging catheter having a flexible housing enclosing a flexible imaging bundle containing a plurality of coherent optical fibers, a circumferential window in said housing adapted for contacting said vessel wall, and a guidewire lumen.
Claim 10
Dependent Claim
34 words
8 . The method of claim 7 further comprising inserting into a vessel lumen of a living subject a guiding catheter having an inflatable occluding balloon, an inflation lumen and a catheter receiving lumen.
Claim 11
Dependent Claim
68 words
9 . The method of claim 6 wherein said step of introducing a heat detecting catheter comprises introducing a thermocouple basket catheter having a point of maximum outer diameter when deployed, at least one channel containing a pair of electrically insulated thermocouple wires, and a thermocouple junction situated at said maximum diameter point and disposed inside said channel between a thermally conductive layer and a thermally insulating layer.
Claim 12
Dependent Claim
47 words
10 . The method of claim 6 wherein said step of introducing a heat detecting catheter comprises introducing a thermistor basket catheter having a point of maximum outer diameter when deployed and at least one channel containing a resistive temperature device situated at said maximum diameter point.
Claim 13
Dependent Claim
48 words
11 . The method of claim 6 wherein said step of introducing a heat detecting catheter comprises introducing a introducing a catheter chosen from the group consisting of an intravascular ultrasound catheter, an intravascular magnetic resonance imaging catheter, a liquid crystal thermometry catheter and a near-infrared spectroscopy catheter.
Claim 14
Dependent Claim
18 words
12 . The method of claim 11 wherein said non-invasive temperature measuring step comprises employing magnetic resonance imaging.
Claim 15
Dependent Claim
33 words
13 . The method of claim 1 or 2 wherein said determining or measuring step comprises non-invasively measuring the temperature of said at least two sites using infrared, microwave, or magnetic resonance imaging.
Claim 16
Dependent Claim
52 words
14 . An infrared imaging catheter comprising a flexible housing enclosing a flexible imaging bundle containing a plurality of coherent optical fibers, said bundle disposed about a guidewire lumen extending longitudinally through said catheter, a circumferential IR transmissive window in said housing adapted for contacting said vessel wall; and a guidewire lumen.
Claim 17
Dependent Claim
52 words
14 . An infrared imaging catheter comprising a flexible housing enclosing a flexible imaging bundle containing a plurality of coherent optical fibers, said bundle disposed about a guidewire lumen extending longitudinally through said catheter, a circumferential IR transmissive window in said housing adapted for contacting said vessel wall; and a guidewire lumen.
Claim 18
Dependent Claim
22 words
15 . The catheter of claim 14 further comprising a reflective surface in optical communication with said window and said optical fibers.
Claim 19
Dependent Claim
22 words
16 . The catheter of claim 14 wherein said plurality of fibers have tips bent radially outward and terminating adjacent said window.
Claim 20
Dependent Claim
12 words
17 . The catheter of claim 14 further comprising a flushing lumen.
Claim 21
Dependent Claim
16 words
18 . The catheter of claim 14 wherein said guidewire lumen is also a flushing lumen.
Claim 22
Dependent Claim
17 words
19 . The catheter of claim 14 further comprising an inflatable occluding balloon and an inflation lumen.
Claim 23
Dependent Claim
60 words
20 . An infrared imaging catheter comprising a flexible housing enclosing a flexible imaging bundle containing a plurality of coherent optical fibers, said bundle disposed about a guidewire/flushing lumen extending longitudinally through said catheter; a circumferential window in said housing adapted for contacting said vessel wall; and a reflective surface in optical communication with said window and said optical fibers.
Claim 24
Dependent Claim
60 words
20 . An infrared imaging catheter comprising a flexible housing enclosing a flexible imaging bundle containing a plurality of coherent optical fibers, said bundle disposed about a guidewire/flushing lumen extending longitudinally through said catheter; a circumferential window in said housing adapted for contacting said vessel wall; and a reflective surface in optical communication with said window and said optical fibers.
Claim 25
Dependent Claim
55 words
21 . An intravascular infrared imaging catheter assembly for detecting temperature heterogeneity along a vessel wall, said assembly comprising: the infrared imaging catheter of claim 20; and a guiding catheter having an inflatable occluding balloon, an inflation lumen in communication with said balloon, and a guiding lumen adapted for slidingly receiving said infrared imaging catheter.
Claim 26
Dependent Claim
22 words
22 . The catheter assembly of claim 21 further comprising means for applying 38° to 45° C. heat to said vessel wall.
Claim 27
Dependent Claim
95 words
23 . An infrared imaging catheter assembly comprising: the catheter of claim 14; an infrared array detector; a signal processor; a microcontroller programmed for receiving, storing, analyzing and reporting temperature information obtained from a plurality of sites along a vessel wall; a display system; and a user interface, said infrared imaging bundle being in optical contact with said infrared array detector, said detector being in electrical contact with said signal processor, said signal processor being in electrical contact with said display system and microcontroller, and said microcontroller being in electrical contact with said user interface.
Claim 28
Dependent Claim
21 words
24 . The catheter assembly of claim 23 further comprising a source of infrared radiation operatively connected to said imaging bundle.
Claim 29
Dependent Claim
154 words
25 . A thermocouple basket catheter for detecting temperature heterogeneity along a vessel wall, the catheter comprising an expandable basket formed by at least four hollow channels and having proximal and distal ends, each said channel having a distal terminus and comprising a thermally conductive material and having a vessel wall-contacting side and a vessel lumen facing side; a hollow shaft joined to said proximal end; a tip joined to said distal end and enclosing each said channel terminus; a thermocouple junction disposed inside each said channel, said junction being longitudinally disposed within each said channel at a point about mid-way between said basket proximal and distal ends, and said junction disposed within each said channel in thermal contact with said vessel wall contacting side and thermally insulated from said lumen facing side; and a pair of insulated thermocouple wires disposed inside each said channel and extending from said junction through said hollow shaft.
Claim 30
Dependent Claim
154 words
25 . A thermocouple basket catheter for detecting temperature heterogeneity along a vessel wall, the catheter comprising an expandable basket formed by at least four hollow channels and having proximal and distal ends, each said channel having a distal terminus and comprising a thermally conductive material and having a vessel wall-contacting side and a vessel lumen facing side; a hollow shaft joined to said proximal end; a tip joined to said distal end and enclosing each said channel terminus; a thermocouple junction disposed inside each said channel, said junction being longitudinally disposed within each said channel at a point about mid-way between said basket proximal and distal ends, and said junction disposed within each said channel in thermal contact with said vessel wall contacting side and thermally insulated from said lumen facing side; and a pair of insulated thermocouple wires disposed inside each said channel and extending from said junction through said hollow shaft.
Claim 31
Dependent Claim
20 words
26 . The thermocouple basket catheter of claim 25 wherein each said channel terminus is fixedly enclosed in said tip.
Claim 32
Dependent Claim
21 words
27 . The thermocouple basket catheter of claim 25 wherein at least one said terminus is moveably enclosed inside said tip.
Claim 33
Dependent Claim
41 words
28 . An intravascular thermocouple catheter assembly for detecting temperature heterogeneity along a vessel wall, said assembly comprising: the thermocouple basket catheter of claim 25; and a guiding catheter having a guiding lumen adapted for slidingly receiving said thermocouple basket catheter.
Claim 34
Dependent Claim
26 words
29 . The assembly of claim 28 wherein said guiding catheter further comprises an inflatable occluding balloon and an inflation lumen in communication with said balloon.
Claim 35
Dependent Claim
14 words
30 . The catheter assembly of claim 28 further comprising an intravascular ultrasound wire.
Claim 36
Dependent Claim
26 words
31 . The assembly of claim 28 further comprising a thermally insulating material disposed inside each said channel between said junction and said lumen facing side.
Claim 37
Dependent Claim
128 words
32 . A thermistor basket catheter for detecting temperature heterogeneity along a vessel wall, the catheter comprising an expandable basket formed by at least four hollow channels and having proximal and distal ends, each said channel having a vessel wall-contacting side and a lumen facing side; a hollow shaft joined to said proximal end; a tip joined to said distal end; a thermistor disposed on the outside of each said channel, said thermistor being longitudinally disposed on each said channel at a point about mid-way between said basket proximal and distal ends on said vessel wall contacting side of each said channel; a pair of insulated wires in electrical contact with each said thermistor and extending from said thermistor through said proximal end and through said hollow shaft.
Claim 38
Dependent Claim
128 words
32 . A thermistor basket catheter for detecting temperature heterogeneity along a vessel wall, the catheter comprising an expandable basket formed by at least four hollow channels and having proximal and distal ends, each said channel having a vessel wall-contacting side and a lumen facing side; a hollow shaft joined to said proximal end; a tip joined to said distal end; a thermistor disposed on the outside of each said channel, said thermistor being longitudinally disposed on each said channel at a point about mid-way between said basket proximal and distal ends on said vessel wall contacting side of each said channel; a pair of insulated wires in electrical contact with each said thermistor and extending from said thermistor through said proximal end and through said hollow shaft.
Claim 39
Dependent Claim
25 words
33 . The catheter of any one of claims 14 , 25 or 32 having an outer diameter of no more than about 6 mm.
Claim 40
Dependent Claim
18 words
34 . The catheter of claim 33 having an outer diameter of no more than about 3 mm.
Claim 41
Dependent Claim
107 words
35 . An assembly for identifying vulnerable atherosclerotic plaque, the assembly comprising: the catheter of claim 14 having an external diameter of no more than 6 mm; an infrared array detector; a signal processor; a microcontroller programmed for receiving, storing, analyzing and reporting temperature information obtained from a plurality of sites along a vessel wall; a display system; and a user interface, said fibers being in optical contact with said infrared array detector, said detector being in electrical contact with said signal processor, said signal processor being in electrical contact with said display system and microcontroller, and said microcontroller being in electrical contact with said user interface.
Claim 42
Dependent Claim
31 words
36 . The assembly of claim 35 further comprising: an infrared radiation source in optical communication with an infrared fiber multiplexer, said multiplexer also being in electrical contact with said microcontroller.
Claim 43
Dependent Claim
65 words
37 . An assembly for identifying vulnerable atherosclerotic plaque, the assembly comprising: the catheter of claim 25 or 32 ; a temperature display system; a microprocessor programmed for receiving, storing, analyzing and reporting temperature information; and a user interface, each said thermocouple or thermistor being in electrical contact with said display system and said microprocessor, said microprocessor being in electrical contact with said user interface.
Claim 44
Dependent Claim
121 words
38 . A method of detecting and monitoring inflammation in a transplanted arteriovenous graft in a living subject, the method comprising: using an infrared camera, non-invasively imaging said arteriovenous graft to obtain an initial infrared thermogram of said graft; subsequent to obtaining said initial thermogram, repeating said infrared imaging to obtain a second infrared thermogram of said graft; subsequent to obtaining said second thermogram, optionally repeating said infrared imaging to obtain at least one subsequent infrared image of said arteriovenous graft; comparing said initial, second and subsequent infrared images to identify temperature changes in a region of said graft; from said temperature changes, determining an increase, decrease or no change in inflammation in at least one region of said arteriovenus graft.
Claim 45
Dependent Claim
121 words
38 . A method of detecting and monitoring inflammation in a transplanted arteriovenous graft in a living subject, the method comprising: using an infrared camera, non-invasively imaging said arteriovenous graft to obtain an initial infrared thermogram of said graft; subsequent to obtaining said initial thermogram, repeating said infrared imaging to obtain a second infrared thermogram of said graft; subsequent to obtaining said second thermogram, optionally repeating said infrared imaging to obtain at least one subsequent infrared image of said arteriovenous graft; comparing said initial, second and subsequent infrared images to identify temperature changes in a region of said graft; from said temperature changes, determining an increase, decrease or no change in inflammation in at least one region of said arteriovenus graft.
Claim 46
Dependent Claim
156 words
39 . A method of evaluating an anti-atherosclerotic interventional therapy in a flowing mammalian artery, the method comprising: feeding cholesterol to a Watanabe hypercholesterolemic rabbit such that visible, palpably warm atherosclerotic lesions extending along the central ear artery develop in said rabbit, whereby an animal model of human atherosclerosis is produced; non-invasively measuring the temperature of at least one region of said ear artery in at least one said animal model to obtain at least one baseline temperature measurement: administering an anti-atherosclerotic interventional treatment to at least one said animal model; administering a suitable control treatment to at least one said animal model; subsequent to said treatments, non-invasively measuring the temperature of at least one region of said artery in at least one said treated animal model to obtain at least one post-treatment temperature measurement; comparing said baseline, control and post-treatment temperature measurements; and detecting any temperature differences in an artery attributable to said interventional treatment.
Claim 47
Dependent Claim
156 words
39 . A method of evaluating an anti-atherosclerotic interventional therapy in a flowing mammalian artery, the method comprising: feeding cholesterol to a Watanabe hypercholesterolemic rabbit such that visible, palpably warm atherosclerotic lesions extending along the central ear artery develop in said rabbit, whereby an animal model of human atherosclerosis is produced; non-invasively measuring the temperature of at least one region of said ear artery in at least one said animal model to obtain at least one baseline temperature measurement: administering an anti-atherosclerotic interventional treatment to at least one said animal model; administering a suitable control treatment to at least one said animal model; subsequent to said treatments, non-invasively measuring the temperature of at least one region of said artery in at least one said treated animal model to obtain at least one post-treatment temperature measurement; comparing said baseline, control and post-treatment temperature measurements; and detecting any temperature differences in an artery attributable to said interventional treatment.
Claim 48
Dependent Claim
18 words
40 . The method of claim 39 wherein said temperature measuring steps comprise employing an infrared imaging camera.
Claim 49
Dependent Claim
152 words
41 . A method of monitoring the progression or amelioration of an atherosclerotic plaque in a flowing mammalian artery, the method comprising: breeding genetically hypercholesterolemic animals characterized by development of atherosclerotic lesions that are histologically similar to human atherosclerotic plaques, whereby an animal model of human atherosclerosis is produced; using the catheter of any one of claims 14 , 25 or 32 , measuring the temperature of a multiplicity of sites along a vessel wall of said animal to obtain a baseline temperature measurement for each said site and recording the physical location of sites alone the vessel wall corresponding to each said temperature measurement; removing said catheter; at a later time, reinserting said catheter and repeating said temperature measurement and recording of physical location steps; and determining a temperature difference between adjacent sites of said vessel wall, and/or determining a temperature difference between each said site and its corresponding baseline temperature.
References Cited (Backward Citations)
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