Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T

Laleh Golestanirad*, Amir Ali Rahsepar, John E. Kirsch, Kenichiro Suwa, Jeremy C. Collins, Leonardo M. Angelone, Boris Keil, Rod S. Passman, Giorgio Bonmassar, Peter Serano, Peter Krenz, Jim DeLap, James C. Carr, Lawrence L. Wald

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

Purpose: To evaluate the local specific absorption rate (SAR) and heating around retained cardiac leads during MRI at 64 MHz (1.5T) and 127 MHz (3T) as a function of RF coil type and imaging landmark. Methods: Numerical models of retained cardiac leads were built from CT and X-ray images of 6 patients with retained cardiac leads. Electromagnetic simulations and bio-heat modeling were performed with MRI RF body and head coils tuned to 64 MHz and 127 MHz and positioned at 9 different imaging landmarks covering an area from the head to the lower limbs. Results: For all patients and at both 1.5T and 3T, local transmit head coils produced negligible temperature rise (DT<0:1C) for ||B1+|| ≤ 3µT. For body imaging with quadrature-driven coils at 1.5T, ΔT during a 10-min scan remained < 3°C at all imaging landmarks for ||B1+|| ≤ 3µT and <6°C for ||B1+|| ≤ 4µT. For body imaging at 3T, ΔT during a 10-min scan remained < 6°C at all imaging landmarks for (Formula presented.). For shorter pulse sequences up to 2 min, ΔT remained < 6°C for ||B1+|| ≤ 3µT. Conclusion: For the models based on 6 patients studied, simulations suggest that MRI could be performed safely using a local head coil at both 1.5T and 3T, and with a body coil at 1.5T with pulses that produced ||B1+|| ≤ 4µT. MRI at 3T could be performed safely in these patients using pulses with ||B1+|| ≤2µT.

Original languageEnglish (US)
Pages (from-to)653-669
Number of pages17
JournalMagnetic resonance in medicine
Volume81
Issue number1
DOIs
StatePublished - Jan 2019

Funding

The mention of commercial products, their sources, or their use in connection with material reported herein is not to be construed as either an actual or implied endorsement of such products by the Department of Health and Human Services. This work was supported by National Institutes of Health, Grant/Award Numbers: K99EB021320, R01EB00684, R01MH111875, and R03EB024705.

Keywords

  • RF heating
  • SAR
  • abandoned lead
  • anatomical models
  • cardiac implanted electronic device
  • computational modeling
  • defibrillator
  • finite element method
  • pacemaker
  • retained lead
  • safety

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Fingerprint

Dive into the research topics of 'Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T'. Together they form a unique fingerprint.

Cite this