US20030125637A1 - Intravascular temperature sensor - Google Patents

Abstract

Devices and methods for detecting vulnerable plaque within a blood vessel are disclosed. A catheter in accordance with the present invention includes an elongate shaft having a proximal end, a distal end, and an outer surface. At least one temperature sensor is disposed proximate to the distal end of the elongate shaft. In one preferred embodiment, the at least one temperature sensor is adapted to contact inner surface of the blood vessel. In another preferred embodiment, at least one temperature sensor is disposed within a channel defined by a body member that is disposed about the elongate shaft.

Description

FIELD OF THE INVENTION
• The present invention relates generally to medical devices for detecting cardiac disease. More particularly, the present invention relates to medical devices for detecting vulnerable plaque within a blood vessel.[0001]
BACKGROUND OF THE INVENTION
• Therapy modalities for heart disease have traditionally focused on treating blood vessels which have become occluded (blocked) or stenotic (narrowed) by calcified plaque deposits. Blood vessels which have become occluded or stenotic in this manner may interrupt the blood flow which supplies oxygen to the heart muscle. Occluded or stenotic blood vessels may be treated with a number of medical procedures including angioplasty and atherectomy. Angioplasty techniques such as percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA) are relatively noninvasive methods of treating restrictions in blood vessels. In these procedures, a balloon catheter is advanced over a guidewire until the balloon is positioned proximate to a restriction in a diseased vessel. The balloon is then inflated and the restriction in the vessel is stretched. During an atherectomy procedure, the stenotic lesion is mechanically cut or abraded away from the blood vessel wall using an atherectomy catheter.[0002]
• Calcified plaque deposit typically comprise hard materials. But, plaque may also comprise soft materials or combinations of soft and hard materials. Soft plaque typically comprises deposits of cholesterol and other fats which build up within the blood vessels as a patient ages. The build up of plaque in the blood vessels is sometimes referred to as atherosclerosis, or hardening of the arteries.[0003]
• Atherosclerosis often begins as a small injury to an artery wall. This injury triggers a cascade of injury and response, inflammation, and healing, which may ultimately lead to the narrowing of the artery. As the atherosclerotic plaque worsens, inflammatory cells, especially macrophages, collect, at the site to isolate, the debris of the damaged tissue. The result is a core of lipid, macrophages or foam cells and nectrotic tissue, covered by a thin fibrous cap of scar tissue. If the fibrous cap becomes weakened or is subjected to excessive mechanical stress, it may rupture, exposing the thrombogenic damaged endothelium and metabolic byproducts to the blood stream. If the resulting blood clot is severe enough, it may occlude the artery. If this obstruction persists in a coronary artery, a myocardial infarction or angina may result.[0004]
• Plaque deposits which are at risk of rupturing are sometimes referred to as vulnerable plaque. Vulnerable plaque typically comprises a core of soft materials covered with a fibrous cap. Many of vulnerable plaque deposits do not limit the flow of blood through the blood vessels. It has recently been appreciated that vulnerable plaques which do not limit flow may be particularly dangerous because they can rupture suddenly causing heart attack and death. This may occur, for example, when the vulnerable plaque ruptures and a blood clot is formed inside the blood vessel lumen causing a blockage.[0005]
• Recently, the pivotal role of inflammation in the progression of athersclerosis has been recognized. A systemic increase in temperature is often associated with infection (e.g., a fever). Likewise, a local infection or localized damage to tissue may result in a localized increase in temperature. An increase in temperature is thought to be caused by the response of the immune system to infection, known as inflammation and an increase in metabolic activity involved in the healing process. It has been observed that the inflamed necrotic core of a vulnerable plaque maintains itself at a temperature which may be one or more degrees Celsius higher than the surrounding tissue. For example, an inflamed plaque in a human heart, where the normal temperature is about 37° C. may be at a temperature as high as 40° C.[0006]
SUMMARY OF THE INVENTION
• The present invention relates generally to medical devices for detecting cardiac disease. More particularly, the present invention relates to medical devices for detecting vulnerable plaque within a blood vessel. A catheter in accordance with one embodiment of the present invention includes an elongate shaft and a plurality of arms fixed to the elongate shaft.[0007]
• The arms preferably have an extended position and a retracted position. A sensor is fixed to each arm proximate a first end thereof. In a preferred embodiment, each sensor contacts the inner surface of a blood vessel when the arms are in the extended position.[0008]
• In a preferred embodiment, a sheath is disposed about the elongate shaft elongate shaft. The arms may be urged into the retracted position by advancing the sheath distally along the elongate shaft.[0009]
• The signal from each sensor may be displayed and/or recorded using a suitable instrument. Variations in these signals may be noted as the catheter is moved proximally and/or distally through the blood vessel thereof thermally mapping the transversed region. The variations in the sensor signal may be correlated with the axial position of the catheter. This information may be used to identify the position of any vulnerable plaque deposits in the blood vessel.[0010]
• In a preferred embodiment, the arms of the catheter expand radially away from the elongate shaft. The angular orientation of plaque deposits within the blood vessel may be identified by observing variations between the signals from the different sensors.[0011]
• For example, sensors which are proximate to vulnerable plaque deposits may read higher temperatures than sensors which are not proximate to vulnerable plaque deposits.[0012]
• A catheter in accordance with an additional embodiment of the present invention includes one arm comprising a spring which is biased to assume an extended position. A sensor is fixed to the arm proximate a first end thereof. This catheter may also be used for mapping the locations of vulnerable plaque deposits within a blood vessel. In a preferred embodiment, the sensor contacts the inner surface of the blood vessel when the arm is in the extended position. In this preferred embodiment, the temperature measured by the sensor may rise when the sensor is proximate to a vulnerable plaque deposit. Variations in the temperature measured by the sensor may be noted as the catheter is moved proximally and/or distally through the blood vessel, and these variations may be correlated to the axial position of vulnerable plaque deposits. Variations in the signal from the sensor may also be noted as the catheter is rotated about it's longitudinal axis. These variations may be correlated to the angular location of vulnerable plaque deposits within the blood vessel.[0013]
• Yet another exemplary embodiment of a catheter in accordance with the present invention includes a body member disposed about an elongate shaft of the catheter. The body member defines a plurality of flow channels and a temperature sensor is disposed within each channel. This catheter may also be used along with methods in accordance with the present invention for mapping the locations of vulnerable plaque deposits within the blood vessel.[0014]
• The body member of the catheter is preferably sized so that an outer surface of the body member is disposed proximate the inner surface of the blood vessel. When this is the case, blood flowing proximate the inner surface of the blood vessel will flow into the channels. Sensors may be used to measure the temperature of the blood flowing through the channels. Blood which flows over a vulnerable plaque deposit will be warmed by the vulnerable plaque deposit. The increased temperature of this blood may be observed and/or recorded using the sensors disposed within the channels.[0015]
• As the catheter is moved proximally and/or distally through the blood vessel, the distal end of the body member will be proximate different portions of the inner surface of the blood vessel. Variations in the signals from the sensors may be noted as the catheter is moved proximally and/or distally through the blood vessel, and these variations may be correlated to the axial position of the catheter. This information may be used to identify an axial component of the position of any vulnerable plaque deposits in the blood vessel.[0016]
• The flow channels and the sensors are preferably disposed radially about the elongate shaft. An angular component of the position of plaque deposits within the blood vessel may be identified by observing variations between the signals from the different sensors. For example, sensors which are proximate vulnerable plaque deposits may read higher temperatures than sensors which are not proximate vulnerable plaque deposits.[0017]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a catheter in accordance with an exemplary embodiment of the present invention;[0018]
• FIG. 2 is a lateral cross-sectional view of a blood vessel, and the catheter of FIG. 1 is shown disposed within a lumen defined by the blood vessel;[0019]
• FIG. 3 is a plan view of a catheter in accordance with an additional exemplary embodiment of the present invention;[0020]
• FIG. 4 is a perspective view of a catheter in accordance with yet another exemplary embodiment of the present invention;[0021]
• FIG. 5 is a perspective view of a catheter in accordance with an exemplary embodiment of the present invention;[0022]
• FIG. 6 is a partial cross sectional view of catheter of FIG. 5;[0023]
• FIG. 7 is a perspective view of a catheter in accordance with still another exemplary embodiment of the present invention;[0024]
• FIG. 8 is a perspective view of a catheter in accordance with still another exemplary embodiment of the present invention;[0025]
• FIG. 9 is a perspective view of a catheter in accordance with still another exemplary embodiment of the present invention;[0026]
• FIG. 10 is a cross sectional perspective view of a catheter in accordance with still another exemplary embodiment of the present invention;[0027]
• FIG. 11 is a cross sectional plan view of the catheter of FIG. 10; and[0028]
• FIG. 12 is a cross sectional plan view of a catheter in accordance with yet another exemplary embodiment of the present invention.[0029]
DETAILED DESCRIPTION OF THE INVENTION
• The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. In some cases, the drawings may be highly diagrammatic in nature. Examples of constructions, materials, dimensions, and manufacturing processes are provided for various elements. Those skilled in the art will recognize that many of the examples provided have suitable alternatives which may be utilized.[0030]
• FIG. 1 is a perspective view of a[0031]catheter100 in accordance with an exemplary embodiment of the present invention.Catheter100 may be used for mapping the locations ofvulnerable plaque deposits22 within ablood vessel20.Catheter100 comprises anelongate shaft102 having adistal end104, a proximal end (not shown in FIG. 1) and anouter surface106.Catheter100 also includes a plurality ofarms108. In the embodiment of FIG. 1, asensor120 is fixed to eacharm108 proximate afirst end122 thereof Asecond end124 of eacharm108 is fixed to elongateshaft102.
• [0032]Arms108 preferably have an extended position and a retracted position. In the embodiment of FIG. 1,arms108 are shown in the extended position. Asheath126 is disposed aboutelongate shaft102.Arms108 may be urged into the retracted position by advancingsheath126 distally alongelongate shaft102. In a preferred embodiment, eachsensor120 contactsinner surface24 ofblood vessel20 whenarms108 are in the extended position.
• Each[0033]sensor120 may comprise a temperature sensor, an ultrasonic sensor, and/or an electromagnetic radiation sensor. In a preferred embodiment, eachsensor120 comprises a temperature sensor. Examples of temperature sensors which may be suitable in some applications include resistance temperature devices (RTD's), thermistors, thermocouples, MEMS (microelectircal mechanical systems).
• [0034]Blood vessel20 includes a plurality ofvulnerable plaque deposits22. Each vulnerable plaque deposit includes acore portion26 comprising a relatively soft material and a cap28 overlaying the core. Ascatheter100 is moved proximally and/or distally throughblood vessel20,sensors120 preferably contact different portions ofinner surface24 ofblood vessel20.
• The signal from each[0035]sensor120 may be displayed and/or recorded using a suitable instrument. Variations in these signals may be noted ascatheter100 is moved proximally and/or distally throughblood vessel20. The variations in the sensor signal may be correlated with the axial position ofcatheter100. This information may be used to identify the position of any vulnerable plaque deposits inblood vessel20.
• FIG. 2 is a lateral cross-sectional view of a[0036]blood vessel20.Catheter100 of FIG. 1 is shown disposed within alumen30 ofblood vessel20.Catheter100 may be used for mapping the location ofvulnerable plaque deposits22 within ablood vessel20 as described above. In FIG. 2, it may be appreciated thatarms108 ofcatheter100 expand radially away fromelongate shaft102. Asensor120 is fixed to eacharm108 proximate afirst end122 thereof. Asecond end124 of eacharm108 is fixed to elongateshaft102. The angular orientation ofplaque deposits22 withinblood vessel20 may be identified by observing variations between the signals from thedifferent sensors120. For example,sensors120 which are proximatevulnerable plaque deposits22 may read higher temperatures thansensors120 which are not proximate vulnerable plaque deposits.
• FIG. 3 is a plan view of a[0037]catheter200 in accordance with an additional exemplary embodiment of the present invention.Catheter200 comprises anelongate shaft202 having adistal end204, a proximal end (not shown in FIG. 3) and anouter surface206.Catheter200 also includes a plurality ofarms208. In the embodiment of FIG. 3, asensor220 is fixed to eacharm208 proximate afirst end222 thereof. Amiddle portion226 of eacharm208 is fixed to elongateshaft202 ofcatheter200, and afree portion228 of eacharm208 extends away fromelongate shaft202. In a preferred embodiment,free portions228 ofarms208 act to stabilize the flow of blood whencatheter200 is disposed within a blood vessel. In the embodiment of FIG. 3,arms208 are shown in the extended position.Arms208 preferably have an extended position and a retracted position.
• FIG. 4 is a perspective view of a[0038]catheter300 in accordance with yet another exemplary embodiment of the present invention.Catheter300 may be used for mapping the locations of vulnerable plaque deposits within a blood vessel.Catheter300 comprises anelongate shaft302 having adistal end304, a proximal end (not shown in FIG. 4) and anouter surface306.
• A[0039]sheath326 is slidingly disposed about a portion ofelongate shaft302. The first ends322 of a plurality ofarms308 are fixed tosheath326. The second end324 of eacharm308 is fixed to a body member330 ofcatheter300. In the embodiment of FIG. 4, body member330 is disposed aboutelongate shaft302 proximatedistal end304. Asensor320 is fixed to eacharm308 betweenfirst end322 and second end324. In the embodiment of FIG. 4,arms308 are shown in the extended position. In a preferred embodiment,arms308 are biased to assume the extended position.Arms308 may be urged into a retracted position by movingsheath326 proximally relative to elongateshaft302.Arms308 may also be urged into the extended position by movingsheath326 distally relative to elongateshaft302. In a preferred embodiment, eachsensor320 contacts the inner surface of a blood vessel whenarms308 are in the extended position.
• Each[0040]sensor320 may comprise various sensor types without deviating from the spirit and scope of the present invention. Examples of sensors which may be suitable in some applications include pressure sensors, ultrasonic sensors, electromagnetic radiation sensors, and temperature sensors. In a preferred embodiment, eachsensor320 comprises a temperature sensor. Temperature sensors which may be suitable in some applications, include resistance temperature devices (RTD's), thermistors, thermocouples, and MEMS.
• FIG. 5 is a perspective view of a[0041]catheter400 in accordance with an exemplary embodiment of the present invention.Catheter400 also includes anarm408 comprisingspring432 which is biased to assume the extended position shown in FIG. 5. Asensor420 is fixed toarm408 proximate afirst end422 thereof. Asecond end424 ofarm408 is fixed to anelongate shaft402.Elongate shaft402 includes adistal end404, a proximal end (not shown in FIG. 5) and anouter surface406.
• In FIG. 5,[0042]catheter400 is shown disposed within ablood vessel20 havingvulnerable plaque deposits22.Catheter400 may be used for mapping the locations of thevulnerable plaque deposits22 withinblood vessel20. In a preferred embodiment,sensor420 contactsinner surface24 ofblood vessel20 whenarm408 is in the extended position shown in FIG. 5. In this preferred embodiment, the temperature measured bysensor420 may rise whensensor420 is proximate avulnerable plaque deposit22.
• Each vulnerable plaque deposit shown in FIG. 5 includes a[0043]core portion26 comprising a relatively soft material and a cap28 overlaying the core. Ascatheter400 is moved proximally and/or distally throughblood vessel20,sensors420 preferably contact different portions ofinner surface24 ofblood vessel20.
• The signal from[0044]sensor420 may be displayed and/or recorded using a suitable instrument. Variations in the signal may be noted ascatheter400 is moved proximally and/or distally throughblood vessel20, and these variations may be correlated with the axial position ofcatheter400. Variations in the signal fromsensor420 may also be noted ascatheter400 is rotated about it's longitudinal axis. These variations may be correlated with the angular orientation ofcatheter400. The information collected fromsensor420 may be used to identify the position of any vulnerable plaque deposits inblood vessel20.
• FIG. 6 is a partial cross sectional view of[0045]catheter400 of FIG. 5. In FIG. 6, it may be appreciated thatcatheter400 includes asheath426 which is disposed aboutelongate shaft402. In the embodiment of FIG. 6,sheath426 has been advanced is distally alongelongate shaft402 so thatarm408 ofcatheter400 is disposed in a retracted position. In FIG. 6 it may be appreciated thatcatheter400 includes acable434 disposed betweensheath426 andelongate shaft402. A distal end ofcable434 is preferably coupled tosensor420 and a proximal end ofcable434 is preferably coupled to an instrument which is adapted to display and/or record a signal fromsensor420. It is to be appreciated, thatcable434 may include any number of conductors. In some applications, the number of conductors may be selected to matchsensor420. For example,sensor420 may comprise a thermocouple having two contacts which are coupled to two conductors ofcable434.
• FIG. 7 is a perspective view of a[0046]catheter500 in accordance with still another exemplary embodiment of the present invention.Catheter500 comprises anelongate shaft502 having a distal end504, a proximal end (not shown in FIG. 7) and anouter surface506. Abody member530 ofcatheter500 is disposed aboutelongate shaft502.Body member530 defines a plurality offlow channels536.
• In the embodiment of FIG. 7, a[0047]sensor520 is disposed within eachflow channel536.Catheter500 also includes areference sensor521 disposed proximate distal end504 ofelongate shaft502.Sensors520 and521 preferably comprises a temperature sensors. Examples of temperature sensors which may be suitable in some applications include resistance temperature devices (RTD's), thermistors, and thermocouples.
• [0048]Catheter500 may be used for mapping the locations of vulnerable plaque deposits within a blood vessel.Body member530 is preferably sized so that anouter surface505 ofbody member530 is disposed proximate the inner surface of a blood vessel. When this is the case, blood flowing proximate the inner surface of the blood vessel will flow into the channels.Sensors520 may be used to measure the temperature of the blood flowing through the channels. Blood which flows over a vulnerable plaque deposit will be warmed by the vulnerable plaque deposit. The increased temperature of this blood may be observed and/or recorded usingsensors520.
• As[0049]catheter500 is moved proximally and/or distally through a blood vessel, the distal end ofbody member530 will be proximate different portions of the inner surface of the blood vessel. Variations in the signals from the sensors may be noted ascatheter500 is moved proximally and/or distally through the blood vessel, and these variations may be correlated axial position ofcatheter500. This information may be used to identify an axial component of the position of any vulnerable plaque deposits in the blood vessel.
• In FIG. 7, it may be appreciated that[0050]flow channels536 andsensors520 are disposed radially aboutelongate shaft502. An angular component of the position of plaque deposits within blood vessel may be identified by observing variations between the signals from thedifferent sensors520. For example,sensors520 which are proximate vulnerable plaque deposits may read higher temperatures thansensors520 which are not proximate vulnerable plaque deposits.
• FIG. 8 is a perspective view of a[0051]catheter600 in accordance with still another exemplary embodiment of the present invention.Catheter600 may be used for mapping the locations of vulnerable plaque deposits within a blood vessel.Catheter600 comprises anelongate shaft602 having adistal end604, a proximal end (not shown in FIG. 8) and anouter surface606. Asensor620 is disposed so that it overlaysouter surface606 ofelongate shaft602. In the embodiment of FIG. 8,sensor620 comprises aflexible substrate640 and aconductive path638.Conductive path638 is coupled to afirst conductor642 and asecond conductor644. In a preferred embodiment, the electrical resistance ofconductive path638 varies with temperature. Also in a preferred embodiment,first conductor642 and asecond conductor644 are insulated.First conductor642 and asecond conductor644 may be insulated, for example, by a layer of shrink tubing overlayingelongate shaft602. In the embodiment of FIG. 8,sensor620 has a generally cylindricalouter surface605. In a preferred embodiment, the shape ofouter surface605 is selected so thatsensor620 contacts the inner surface of a blood vessel across a substantial area.
• FIG. 9 is a perspective view of a[0052]catheter700 in accordance with still another exemplary embodiment of the present invention.Catheter700 may be used for mapping the locations of vulnerable plaque deposits within a blood vessel.Catheter700 comprises anelongate shaft702 having adistal end704, a proximal end (not shown in FIG. 9) and anouter surface706.Catheter700 also includes asensor720 disposed proximatedistal end704 ofelongate shaft702. In the embodiment of FIG. 9,sensor720 comprises abody746 having a generally cylindrical shape. In a preferred embodiment, the shape ofbody746 is selected so thatsensor720 contacts the inner surface of a blood vessel across a substantial area. Afirst conductor742 and asecond conductor744 are coupled tosensor720. In a preferred embodiment, a temperature recording and displaying instrument may interrogatesensor720 viafirst conductor742 andsecond conductor744.
• FIG. 10 is a cross sectional perspective view of a[0053]catheter800 in accordance with still another exemplary embodiment of the present invention.Catheter800 comprises anelongate shaft802 having anouter surface806. Aballoon850 ofcatheter800 is disposed aboutelongate shaft802.
• [0054]Catheter800 also includes anarray852 comprising plurality ofcowls854 circumferentially disposed aboutballoon850.Cowls854 are preferably fixed toballoon850. Eachcowl854 defines aninlet port856, anoutlet port858, and aflow channel836 extending therebetween.
• A sensor[0055]820 (not shown in FIG. 10) is preferably disposed within eachflow channel836. Eachsensor820 preferably comprises a temperature sensor. Examples of temperature sensors which may be suitable in some applications include resistance temperature devices (RTD's), thermistors, and thermocouples.
• [0056]Balloon850 preferably has an inflated state and a deflated state. In the embodiment of FIG. 10,balloon850 is disposed outside of a blood vessel, and is shown in an inflated state. In a preferred embodiment,balloon850 is configured such thatcowls854 are urged radially away fromelongate shaft802 whenballoon850 is in the inflated state.
• FIG. 11 is a cross sectional plan view of[0057]catheter800 of FIG. 10. In FIG. 11, asensor820 may be seen disposed within eachflow channel836. Eachflow channel836 is defined by acowl854 that is preferably fixed toballoon850.Balloon850 is disposed aboutelongate shaft802.
• In the embodiment of FIG. 11,[0058]balloon850 is disposed outside of a blood vessel, and is shown in an inflated state.Balloon850 may be inflated, for example, by urging a fluid through aninflation lumen860 and aninflation port862 defined byelongate shaft802.
• [0059]Balloon850 is preferably configured such thatcowls854 will be urged against the inner surface of a blood vessel whenballoon850 is placed in the inflated state whilecatheter800 is disposed within the blood vessel.Balloon850 is preferably configured such that blood flow aroundcowls854 will be precluded whenballoon850 is in the inflated state.
• Blood flowing proximate the inner surface of the blood vessel preferably flows through[0060]flow channels836 defined bycowls854.Sensors820 may be used to measure the temperature of the blood flowing through the channels. Blood which flows over a vulnerable plaque deposit will be warmed by the vulnerable plaque deposit. The increased temperature of this blood may be observed and/or recorded usingsensors820.
• FIG. 12 is a cross sectional plan view of a[0061]catheter900 in accordance with yet another exemplary embodiment of the present invention.Catheter900 comprises anelongate shaft902 having anouter surface906. Aballoon950 ofcatheter900 is disposed aboutelongate shaft902.
• [0062]Catheter900 also includes aarray952 comprising plurality ofcowls954 circumferentially disposed aboutballoon950. In the embodiment of FIG. 12, each cowl has a generally wedge shaped cross-sectional shape. Eachcowl954 is preferably fixed toballoon950.
• Each[0063]cowl954 defines aflow channel936. Asensor920 is preferably disposed within eachflow channel936. Eachsensor920 preferably comprises a temperature sensor. Examples of temperature sensors which may be suitable in some applications include resistance temperature devices (RTD's), thermistors, and thermocouples.
• [0064]Balloon950 preferably has an inflated state and a deflated state. In the embodiment of FIG. 12,balloon950 is disposed within ablood vessel20, and is shown in an inflated state. In a preferred embodiment,balloon950 is configured such thatcowls954 are urged radially away fromelongate shaft902 whenballoon950 is in the inflated state. In FIG. 12, it may be appreciated thatcowls954 have been urged against aninner surface24 ofblood vessel20 byballoon950.Balloon950 may be inflated, for example, by urging a fluid through aninflation lumen960 and aninflation port962 defined byelongate shaft902.
• [0065]Balloon950 is preferably configured such that blood flow aroundcowls954 will be precluded whenballoon950 is in the inflated state. Blood flowing proximateinner surface24 ofblood vessel20 preferably flows intoflow channels936 defined bycowls954.Sensors920 may be used to measure the temperature of the blood flowing through the channels. Blood which flows over a vulnerable plaque deposit will be warmed by the vulnerable plaque deposit. The increased temperature of this blood may be observed and/or recorded usingsensors920.
• Having thus described the preferred embodiments of the present invention, those of skill in the art will readily appreciate that yet other embodiments may be made and used within the scope of the claims hereto attached. Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.[0066]

Claims (33)

What is claimed is:

1. A catheter for mapping vulnerable plaque deposits within a blood vessel, comprising;

an elongate shaft having a proximal end and a distal end;

at least one cowl fixed to the elongate shaft proximate the distal end thereof;

the at least one cowl defining an inlet port, an outlet port, and a flow channel extending therebetween; and

at least one temperature sensor disposed within the flow channel defined by the at least one cowl.

2. The catheter ofclaim 1, wherein the at least one temperature sensor is adapted to measure the temperature of blood passing through the flow channel.

3. The catheter ofclaim 1, wherein the at least one temperature sensor is adapted to measure the temperature of blood passing through the flow channel; and

the at least one cowl is configured such temperature of the blood passing through the flow channel is reflective of the temperature of inner surface of the blood vessel proximate the distal end of the catheter.

4. The catheter ofclaim 1, wherein the temperature sensor comprises a resistance temperature device.

5. The catheter ofclaim 1, wherein the temperature sensor comprises a thermocouple.

6. The catheter ofclaim 1, wherein the temperature sensor comprises a thermistor.

7. The catheter ofclaim 1, wherein the temperature sensor comprises a microbolometer.

8. The catheter ofclaim 1, further comprising an interstitial member disposed between the at least one cowl and the elongate shaft.

9. The catheter ofclaim 1, further comprising a balloon disposed between the at least one cowl and the elongate shaft.

10. The catheter ofclaim 1, wherein the balloon has an inflated state and a deflated state.

11. The catheter ofclaim 1, wherein the balloon is configured such that the flow of blood around the at least one cowl is precluded when the balloon is in the inflated state.

12. The catheter ofclaim 1, wherein the balloon is configured such that the at least one cowl urged radially away from the elongate shaft when the balloon is in the inflated state.

13. The catheter ofclaim 1, further comprising a plurality of cowls radially disposed about the elongate shaft.

14. A catheter for mapping vulnerable plaque deposits within a blood vessel, comprising;

an elongate shaft having a proximal end and a distal end;

a plurality of cowls radially disposed about the elongate shaft proximate the distal end thereof;

each cowl defining an inlet port, an outlet port, and a flow channel extending therebetween; and

a temperature sensor disposed within each flow channel.

15. The catheter ofclaim 14, wherein each temperature sensor comprises a resistance temperature device.

16. The catheter ofclaim 14, wherein each temperature sensor comprises a thermocouple.

17. The catheter ofclaim 14, wherein each temperature sensor comprises a thermistor.

18. The catheter ofclaim 14, wherein each temperature sensor comprises a microbolometer.

19. The catheter ofclaim 14, further comprising an interstitial member disposed between the cowls and the elongate shaft.

20. The catheter ofclaim 14, further comprising a balloon disposed between the at least one cowl and the elongate shaft.

21. The catheter ofclaim 20, wherein the balloon has an inflated state and a deflated state.

22. The catheter ofclaim 21, wherein the balloon is configured such that the flow of blood around the cowls is precluded when the balloon is in the inflated state.

23. The catheter ofclaim 21, wherein the balloon is configured such that the cowls urged radially away from the elongate shaft when the balloon is in the inflated state.

24. A catheter for mapping vulnerable plaque deposits within a blood vessel, comprising;

an elongate shaft having a proximal end and a distal end;

an array of cowls radially disposed about the elongate shaft proximate the distal end thereof;

each cowl of the array of cowls defining an inlet port, an outlet port, and a flow channel extending therebetween;

a temperature sensor disposed within each flow channel; and

a means for radially expanding the array of cowls.

25. The catheter ofclaim 24, wherein each temperature sensor comprises a resistance temperature device.

26. The catheter ofclaim 24, wherein each temperature sensor comprises a thermocouple.

27. The catheter ofclaim 24, wherein each temperature sensor comprises a thermistor.

28. The catheter ofclaim 24, wherein each temperature sensor comprises a microbolometer.

29. The catheter ofclaim 24, wherein the means for radially expanding the array of cowls comprises a hydraulic mechanism.

30. The catheter ofclaim 29, wherein the means for radially expanding the array of cowls comprises a balloon.

31. The catheter ofclaim 30, wherein the balloon is configured such that the flow of blood around the cowls is precluded when the balloon is in the inflated state.

32. The catheter ofclaim 24, wherein the means for radially expanding the array of cowls comprises a mechanical mechanism.

33. The catheter ofclaim 29, wherein the means for radially expanding the array of cowls comprises a plurality of resilient arms.

Images