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 language | English (US) |
|---|---|
| Pages (from-to) | 653-669 |
| Number of pages | 17 |
| Journal | Magnetic resonance in medicine |
| Volume | 81 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2019 |
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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
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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 journal › Article
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
M3 - Article
VL - 81
SP - 653
EP - 669
JO - Magnetic Resonance in Medicine
JF - Magnetic Resonance in Medicine
SN - 0740-3194
IS - 1
ER -