Measurement of Radiofrequency Induced Heating in Patients with Retained Post-Surgical Epicardial Leads During MRI

In the 2017 Heart Rhythm Society consensus statements, scanning of nonconditional cardiac implantable electronic devices in the presence of epicardial leads were classified as contraindications in MRI. Much of the concerns were due to the possibility for the lead to interact with the radiofrequency (RF) field produced in the MRI scanner, causing a significant amount of heating in the patient. While there are numerous studies on transvenous leads, there is insufficient data to comment on the safety of patients with retained post-surgical epicardial wires during MRI. In this study, bipolar and unipolar post-surgical epicardial wires were placed inside a tissue-equivalent phantom and scanned using a turbo spin echo pulse sequence that produced a whole-body SAR of ~2 W/kg on a 3 T MRI system. The phantom was designed according to the ASTM standard for measurement of RF-induced heating on or near passive implants. The properties of the phantom including its dielectric constant, electrical conductivity, specific heat, and thermal conductivity were characterized and found to agree with the recommended ASTM values for tissue equivalence and highlight the clinical importance of the results from the study. Findings for both types of leads indicate that patients with retained post-surgical leads with lengths < 13 cm may safely undergo an MRI scan without concern for significant heating. Also, although the amount of heat induced in the leads was found to increase with lead length, the orientation, shape, and position of the lead in the patients must be considered when justifying the diagnostic need of the scan with its attendant risk to the patients.

Grantor dc:publisher

Creighton University

Year dc:date.issued

2021

Author dc:creator

• Aboyewa, Oluyemi

Advisor dc:contributor.advisor

• Nichols, Michael G.

Statement dc:rights

• Copyright is retained by the Author. A non-exclusive distribution right is granted to Creighton University and to ProQuest following the publishing model selected above.

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10504/130597

OAI identifier oai:identifier

oai:cdr.creighton.edu:10504/130597