# US 2010/0168570 A1 · Methods and Apparatus for Utilizing Impeller-Based Rotationally-Scanning Catheters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0168570 A1 - Document ID: US20100168570A1 - Status: Published application - Kind: A1 - Application number: 12/347,116 - Filed: 2008-12-31 - Published: 2010-07-01 - Earliest claimed: 2008-12-31 - Assignees: St. Jude Medical, Atrial Fibrillation Division, Inc. - Inventors: John W. Sliwa; Zhenyi Ma - Web page: https://patentgrep.com/patent/US20100168570A1 ## CPC - A61B 8/4461: {Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe} - A61B 8/12: in body cavities or body tracts, e.g. by using catheters - A61B 8/4281: {characterised by sound-transmitting media or devices for coupling the transducer to the tissue} - A61B 8/445: {Details of catheter construction} - A61B 18/02: by cooling, e.g. cryogenic techniques - A61B 18/14: Probes or electrodes therefor - A61B 18/18: by applying electromagnetic radiation, e.g. microwaves - A61B 18/20: using laser - A61B 2018/00029: {open} - A61B 2090/3782: {transmitter or receiver in catheter or minimal invasive instrument} - A61B 2090/3784: {both receiver and transmitter being in the instrument or receiver being also transmitter} - A61B 2218/002: Irrigation - A61N 7/02: Localised ultrasound hyperthermia - A61N 7/022: {intracavitary} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract An ablation catheter includes a tubular catheter body having a lumen, a tip portion, a liquid inlet, at least one liquid outlet, a liquid flow path defined between the liquid inlet and the liquid outlet, and an ablation element mounted on the tip portion of the catheter body. A rotationally-scanning ultrasound assembly is disposed within the lumen of the catheter body adjacent the tip portion. The ultrasound assembly includes an ultrasound transducer having an active face, an acoustic mirror acoustically coupled to the active face of the ultrasound transducer, and an impeller positioned in the liquid flow path and operably coupled to at least one of the ultrasound transducer and the acoustic mirror to impart rotational motion thereto when a liquid flows through the impeller. ## Claims ### Claim 1 A catheter comprising: a tubular catheter body having a tip portion and a lumen; a rotationally-scanning ultrasound assembly disposed adjacent the tip portion, the rotationally-scanning ultrasound assembly comprising an ultrasound transducer having an active face; and a drive assembly including an impeller operably coupled to the rotationally-scanning ultrasound assembly such that a liquid flowing through the impeller imparts rotational motion to the ultrasound assembly. ### Claim 2 (depends on 1) The catheter according to claim 1, wherein the impeller is operably coupled to the ultrasound transducer to impart rotational motion to the ultrasound transducer. ### Claim 3 (depends on 1) The catheter according to claim 1, wherein the ultrasound assembly further comprises an acoustic mirror adapted to be acoustically coupled to the active face of the ultrasound transducer via an acoustic coupling medium. ### Claim 4 (depends on 3) The catheter according to claim 3, wherein the acoustic coupling medium comprises a liquid flowed through the impeller. ### Claim 5 (depends on 3) The catheter according to claim 3, wherein the impeller is operably coupled to the acoustic mirror to impart rotational motion to the acoustic mirror. ### Claim 6 (depends on 5) The catheter according to claim 5, wherein the ultrasound transducer is non-rotating. ### Claim 7 (depends on 3) The catheter according to claim 3, wherein the acoustic mirror is positioned proximally of the ultrasound transducer. ### Claim 8 (depends on 3) The catheter according to claim 3, wherein the acoustic mirror is positioned distally of the ultrasound transducer. ### Claim 9 (depends on 1) The catheter according to claim 1, wherein the ultrasound assembly further comprises an acoustic lens adapted to be acoustically coupled to the active face of the ultrasound transducer via an acoustic coupling medium. ### Claim 10 (depends on 1) The catheter according to claim 1, wherein the impeller includes a central passageway to accommodate at least one electrical wire routed through the lumen. ### Claim 11 (depends on 1) The catheter according to claim 1, wherein the lumen of the catheter body includes a plurality of outlet ports to exhaust a liquid flowing through the impeller adjacent the tip portion. ### Claim 12 (depends on 1) The catheter according to claim 1, wherein two or more of an impeller blade rake angle, a liquid flow rate, and a liquid pressure are selected or controlled such that the impeller rotates at between about 10 rpm and 20 rpm when a liquid flows into the impeller. ### Claim 13 (depends on 1) The catheter according to claim 1, wherein the tip portion of the catheter body includes an ablation element. ### Claim 14 (depends on 13) The catheter according to claim 13, wherein the ablation element is an RF ablation element. ### Claim 15 (depends on 1) The catheter according to claim 1, wherein the ultrasound assembly is oriented to provide a visualization field adjacent the tip portion of the catheter body. ### Claim 16 (depends on 1) The catheter according to claim 1, wherein the ultrasound assembly is slidably mounted within the lumen of the tubular catheter body. ### Claim 17 An ablation catheter comprising: a tubular catheter body comprising: a lumen; a tip portion; a liquid inlet; at least one liquid outlet; and a liquid flow path defined between the liquid inlet and the liquid outlet; an ablation element mounted on the tip portion of the catheter body; and a rotationally-scanning ultrasound assembly disposed within the lumen of the catheter body adjacent the tip portion, the rotationally-scanning ultrasound assembly comprising: an ultrasound transducer having an active face; an acoustic mirror acoustically coupled to the active face of the ultrasound transducer; and an impeller positioned in the liquid flow path and operably coupled to at least one of the ultrasound transducer and the acoustic mirror to impart rotational motion thereto when a liquid flows through the impeller. ### Claim 18 (depends on 17) The catheter according to claim 17, wherein at least one of the ultrasound transducer and the acoustic mirror is oriented non-orthogonally to a central axis of the catheter body such that the ultrasound assembly provides a visualization field adjacent the tip portion of the catheter body. ### Claim 19 (depends on 17) The catheter according to claim 17, wherein the ultrasound transducer is positioned distally of the acoustic mirror and oriented with the active face facing proximally. ### Claim 20 (depends on 17) The catheter according to claim 17, wherein the ultrasound transducer is positioned proximally of the acoustic mirror and oriented with the active face facing distally. ### Claim 21 (depends on 17) The catheter according to claim 17, further comprising a fluid disposed between the ultrasound transducer and the acoustic mirror to acoustically couple the acoustic mirror to the active face of the ultrasound transducer. ### Claim 22 (depends on 17) The catheter according to claim 17, wherein the tubular catheter body comprises a material selected to minimize reflections and ringing of ultrasonic energy propagating therethrough. ### Claim 23 (depends on 22) The catheter according to claim 22, wherein the tubular catheter body comprises polyethylene. ### Claim 24 (depends on 17) The catheter according to claim 17, wherein the acoustic mirror and the impeller are formed as a unitary assembly. ### Claim 25 (depends on 17) The catheter according to claim 17, wherein the acoustic mirror is affixed to the impeller. ### Claim 26 (depends on 17) The catheter according to claim 17, wherein the at least one liquid outlet is positioned to exhaust a liquid flowing through the liquid flow path adjacent the tip portion. ### Claim 27 (depends on 17) The catheter according to claim 17, wherein the liquid flow path includes an outlet segment between the impeller and the at least one liquid outlet, and wherein the outlet segment is configured to return a liquid flowing through the liquid flow path to a proximal end of the catheter. ### Claim 28 A method of assessing tissue, comprising: providing a catheter comprising: a tubular catheter body having a tip portion, an ablation element mounted on the tip portion, and a lumen; a rotationally-scanning ultrasound assembly disposed within the lumen adjacent the tip portion and including an ultrasound transducer having an active face, wherein the ultrasound assembly provides a visualization field adjacent the tip portion of the catheter body; and an impeller operably coupled to the ultrasound assembly to impart rotational motion thereto; placing the tip portion of the catheter adjacent tissue to be assessed; and flowing a liquid through the impeller, thereby rotating the ultrasound assembly. ### Claim 29 (depends on 28) The method according to claim 28, further comprising exhausting the liquid adjacent the tip portion to irrigate the tissue to be assessed. ### Claim 30 (depends on 28) The method according to claim 28, wherein the ultrasound assembly further comprises an acoustic mirror acoustically coupled to the active face of the ultrasound transducer and operably coupled to the impeller, and wherein step of flowing a liquid through the impeller comprises flowing a liquid through the impeller to rotate the mirror. ### Claim 31 (depends on 28) The method according to claim 28, further comprising monitoring a rotational position of the ultrasound assembly. ### Claim 32 (depends on 28) The method according to claim 28, further comprising generating a three dimensional image of a tissue within the visualization field. ### Claim 33 (depends on 28) The method according to claim 28, further comprising monitoring creation of an ablation lesion of a tissue within the visualization field. ### Claim 34 A method of manufacturing an ablation catheter, comprising: providing a tubular catheter body having a tip portion and a lumen; mounting an ablation element on the tip portion; placing a rotationally-scanning ultrasound assembly within the lumen adjacent the tip portion, the ultrasound assembly including a transducer; and operably coupling an impeller to the ultrasound assembly to impart rotational motion to the ultrasound assembly when a liquid flows through the impeller. ### Claim 35 (depends on 34) The method according to claim 34, further comprising micromolding the impeller. ### Claim 36 (depends on 34) The method according to claim 34, wherein the step of operably coupling the impeller to the ultrasound assembly comprises operably coupling the impeller to the transducer. ### Claim 37 (depends on 34) The method according to claim 34, wherein the ultrasound assembly further comprises an acoustic mirror acoustically coupled to the transducer, and the step of operably coupling the impeller to the ultrasound assembly comprises operably coupling the impeller to the acoustic mirror. ### Claim 38 (depends on 37) The method according to claim 37, wherein the step of operably coupling the impeller to the acoustic mirror comprises micromolding a unitary assembly including the impeller and the acoustic mirror. ### Claim 39 (depends on 34) The method according to claim 34, wherein the impeller includes a central passageway, further comprising the steps of: providing at least one lead; attaching an end of the at least one lead to at least one of the ablation element and the transducer; and routing the lead proximally through the central passageway of the impeller.