title: In vivo evaluation and proof of radiofrequency safety of a novel diagnostic MR-electrophysiology catheter.
abstract: An MR-electrophysiology (EP) catheter is presented that provides full diagnostic EP functionality and a high level of radiofrequency safety achieved by custom-designed transmission lines. Highly resistive wires transmit intracardiac electrograms and currents for intracardiac pacing. A transformer cable transmits the localization signal of a tip coil. Specific absorption rate simulations and temperature measurements at 1.5 T demonstrate that a wire resistance > 3 kΩ/m limits dielectric heating to a physiologically irrelevant level. Additional wires do not increase tip specific absorption rate significantly, which is important because some clinical catheters require up to 20 electrodes. It is further demonstrated that radiofrequency-induced and pacing-induced resistive heating of the wires is negligible under clinical conditions. The MR-EP catheters provided uncompromised recording of electrograms and cardiac pacing in combination with a standard EP recorder in MR-guided in vivo EP studies, and the tip coil enabled fast and robust catheter localization. In vivo temperature measurements during such a study did not detect any device-related heating, which confirms the high level of safety of the catheter, whereas unacceptable heating was found with a standard EP catheter. The presented concept for the first time enables catheters with full diagnostic EP functionality and active tracking and at the same time a sufficient level of radiofrequency safety for MRI without specific absorption rate-related limitations.
authors.affiliation: Philips Technologie GmbH Forschungslaboratorien, Sector Imaging Systems and Intervention, Hamburg, Germany. Steffen.Weiss@philips.com
authors.forename: Steffen
authors.initials: S
authors.lastname: Weiss
authors.forename: Daniel
authors.initials: D
authors.lastname: Wirtz
authors.forename: Bernd
authors.initials: B
authors.lastname: David
authors.forename: Sascha
authors.initials: S
authors.lastname: Krueger
authors.forename: Oliver
authors.initials: O
authors.lastname: Lips
authors.forename: Dennis
authors.initials: D
authors.lastname: Caulfield
authors.forename: Steen Fjord
authors.initials: SF
authors.lastname: Pedersen
authors.forename: Julian
authors.initials: J
authors.lastname: Bostock
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
mesh_terms: D000818:Animals; D002058:Burns, Electric / Q000209:etiology / Q000517:prevention & control; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac / Q000009:adverse effects / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000295:instrumentation*; D011846:Radio Waves / Q000009:adverse effects; D013552:Swine