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Vertical open‐bore MRI scanners generate significantly less radiofrequency heating around implanted leads: A study of deep brain stimulation implants in 1.2T OASIS scanners versus 1.5T horizontal systems
Author(s) -
Kazemivalipour Ehsan,
Bhusal Bhumi,
Vu Jasmine,
Lin Stella,
Nguyen Bach Thanh,
Kirsch John,
Nowac Elizabeth,
Pilitsis Julie,
Rosenow Joshua,
Atalar Ergin,
Golestanirad Laleh
Publication year - 2021
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28818
Subject(s) - imaging phantom , scanner , dielectric heating , biomedical engineering , radiofrequency coil , electromagnetic coil , magnetic resonance imaging , materials science , nuclear medicine , lead (geology) , deep brain stimulation , medicine , computer science , radiology , physics , optoelectronics , geology , artificial intelligence , disease , pathology , geomorphology , parkinson's disease , dielectric , quantum mechanics
Purpose Patients with active implants such as deep brain stimulation (DBS) devices are often denied access to MRI due to safety concerns associated with the radiofrequency (RF) heating of their electrodes. The majority of studies on RF heating of conductive implants have been performed in horizontal close‐bore MRI scanners. Vertical MRI scanners which have a 90° rotated transmit coil generate fundamentally different electric and magnetic field distributions, yet very little is known about RF heating of implants in this class of scanners. We performed numerical simulations as well as phantom experiments to compare RF heating of DBS implants in a 1.2T vertical scanner (OASIS, Hitachi) compared to a 1.5T horizontal scanner (Aera, Siemens). Methods Simulations were performed on 90 lead models created from post‐operative CT images of patients with DBS implants. Experiments were performed with wires and commercial DBS devices implanted in an anthropomorphic phantom. Results We found significant reduction of 0.1 g‐averaged specific absorption rate (30‐fold, P < 1 × 10 −5 ) and RF heating (9‐fold, P < .026) in the 1.2T vertical scanner compared to the 1.5T conventional scanner. Conclusion Vertical MRI scanners appear to generate lower RF heating around DBS leads, providing potentially heightened safety or the flexibility to use sequences with higher power levels than on conventional systems.