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

Laleh Golestani Rad, 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 Carr, Lawrence L. Wald

Research output: Contribution to journalArticle

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 1 2019

Fingerprint

Head
Patient Simulation
X Ray Computed Tomography
Electromagnetic Phenomena
Heating
Lower Extremity
Hot Temperature
Temperature

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

Cite this

Golestani Rad, Laleh ; Rahsepar, Amir Ali ; Kirsch, John E. ; Suwa, Kenichiro ; Collins, Jeremy C. ; Angelone, Leonardo M. ; Keil, Boris ; Passman, Rod S ; Bonmassar, Giorgio ; Serano, Peter ; Krenz, Peter ; DeLap, Jim ; Carr, James ; Wald, Lawrence L. / Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T. In: Magnetic Resonance in Medicine. 2019 ; Vol. 81, No. 1. pp. 653-669.
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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.",
keywords = "RF heating, SAR, abandoned lead, anatomical models, cardiac implanted electronic device, computational modeling, defibrillator, finite element method, pacemaker, retained lead, safety",
author = "{Golestani Rad}, Laleh and Rahsepar, {Amir Ali} and Kirsch, {John E.} and Kenichiro Suwa and Collins, {Jeremy C.} and Angelone, {Leonardo M.} and Boris Keil and Passman, {Rod S} and Giorgio Bonmassar and Peter Serano and Peter Krenz and Jim DeLap and James Carr and Wald, {Lawrence L.}",
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Golestani Rad, L, Rahsepar, AA, Kirsch, JE, Suwa, K, Collins, JC, Angelone, LM, Keil, B, Passman, RS, Bonmassar, G, Serano, P, Krenz, P, DeLap, J, Carr, J & Wald, LL 2019, 'Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T' Magnetic Resonance in Medicine, vol. 81, no. 1, pp. 653-669. https://doi.org/10.1002/mrm.27350

Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T. / Golestani Rad, Laleh; Rahsepar, Amir Ali; Kirsch, John E.; Suwa, Kenichiro; Collins, Jeremy C.; Angelone, Leonardo M.; Keil, Boris; Passman, Rod S; Bonmassar, Giorgio; Serano, Peter; Krenz, Peter; DeLap, Jim; Carr, James; Wald, Lawrence L.

In: Magnetic Resonance in Medicine, Vol. 81, No. 1, 01.01.2019, p. 653-669.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T

AU - Golestani Rad, Laleh

AU - Rahsepar, Amir Ali

AU - Kirsch, John E.

AU - Suwa, Kenichiro

AU - Collins, Jeremy C.

AU - Angelone, Leonardo M.

AU - Keil, Boris

AU - Passman, Rod S

AU - Bonmassar, Giorgio

AU - Serano, Peter

AU - Krenz, Peter

AU - DeLap, Jim

AU - Carr, James

AU - Wald, Lawrence L.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - 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.

AB - 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.

KW - RF heating

KW - SAR

KW - abandoned lead

KW - anatomical models

KW - cardiac implanted electronic device

KW - computational modeling

KW - defibrillator

KW - finite element method

KW - pacemaker

KW - retained lead

KW - safety

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U2 - 10.1002/mrm.27350

DO - 10.1002/mrm.27350

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