SCMR 23rd Annual Scientific Sessions

SCMR/ISMRM Co-Provided Workshop

SCMR/ISMRM Co-provided Workshop: Session 6: There's Not Just an App for That: Innovations in CMR Hardware

7 - Swine validation of an MBalun-equiped device-set of actively-tracked metallic devices for conventional and MR-guided electrophysiological intervention

Thursday, February 13, 2020

9:56 AM – 10:08 AM

Location: Canary 3 & 4

Background: We previously demonstrated Miniature Balun (MBalun) radio-frequency (rf) traps [1,2] that rendered a metallic-backbone (reinforced with metallic tubes or braids) electrophysiology (EP) catheter MRI-conditional, preserving the advantages of metallic torquability and pushability, while ameliorating all rf-induced heating during during high Specific Absorption Rate (SAR) sequences. We subsequently developed a 3-20 French set of actively-tracked MBalun-equipped metallic devices for EP interventions and integrated them with a navigational interface based on 3D Slicer and a Twilight [3] sequence to assesss acute 500-KHz RF-Ablation (RFA) lesions. The devices are tracked with impedance-tracking (IMP) electrodes or MR-Tracking (MRT) coils. We tested the devices' thermal, navigational and ablative performance.

Methods: The Metallic device set (Fig. 1. A-E): 3 Fr active guidewire with 2 MRT; 4 Fr trans-septal ("Baylis") RF needle with 1 MP; 8.5 Fr EP catheter with 4 MRT and 5 IMP; 15 Fr deflectable sheath with 2 MRT and 3 IMP; 20 Fr deflectable Intracardiac MRI (ICMRI) catheter with 5 MRT, 1 MP and a 35-mm expanded diameter imaging coil on tip. Heat Mitigation was validated in gel phantoms with 4 Watt/kg SAR sequences @ 1.5T. Left and Right heart procedures in swine (N=5) included active navigation using MRT or IMP on SSFP-based roadmaps, followed by RFA delivery and Twilight [3] RFA-lesion assessment.

Results: All MBalun-equipped devices heated by < 2^o Celsius during thermal testing (Fig. 1 F,G). Combined sheath and catheter manipulation with 3D-Slicer visualization permitted navigation and RFA in the left ventricle, right and left atrium with Twilight estimation of thermal-dose sufficiency ( > 52^o C) to produce permanent necrotic lesions (Fig. 2).

Conclusion: MBaluns allow construction of active MRI-conditional metallic devices with equivalent performance to conventional devices.

Presenting Author(s)

Ehud J. Schmidt, PhD

MRI Physicist
Johns Hopkins Medicine

Disclosure: Disclosure information not submitted.

Primary Author(s)

Ehud J. Schmidt, PhD

MRI Physicist
Johns Hopkins Medicine

Disclosure: Disclosure information not submitted.

Co-Author(s)

Aravindan J. Kolandaivelu, MD

Assistant Professor
Johns Hopkins Medicine

Disclosure: Disclosure information not submitted.
JT

Junichi Tokuda, PhD

Brigham and Womens' Hospital

Disclosure: Disclosure information not submitted.
MG

Michael Guttman, MSc

Sr. Staff Scientist
Johns Hopkins Medicine

Disclosure: Disclosure information not submitted.
Henry R. Halperin, MD, MSc

Electrophysiologist
Johns Hopkins Medicine

Disclosure: Imricor: Royalties
GO

Gregory K. Olson, BSc

R&D Engineering
Abbott Laboratories

Disclosure: Disclosure information not submitted.
Akbar Alipour, PhD

Research associate
Johns Hopkins Medicine

Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.
JS

Jefffrey Schweitzer, MSc

Abbott Laboratories

Disclosure: Disclosure information not submitted.