The effect of device configuration and patient body composition on image artifact and RF heating of deep brain stimulation devices during MRI at 1.5T and 3T

BACKGROUNDPatients with deep brain stimulation (DBS) implants have limited access to MRI due to safety concerns associated with RF-induced heating. Currently, MRI in these patients is allowed only in 1.5T horizontal scanners and with pulse sequences with reduced power. Nevertheless, off-label use of MRI at 3T is increasingly reported based on limited safety assessments. Here we present results of systematic RF heating measurements for two commercially available DBS systems during MRI at 1.5T and 3T. PURPOSETo assess the effect of imaging landmark, DBS lead configuration, and patient body composition on RF heating of DBS leads during MRI at 1.5 T and 3T. STUDY TYPEPhantom study. POPULATION/SUBJECTS/PHANTOM/SPECIMEN/ANIMAL MODELGel phantoms and cadaver brain. FIELD STRENGTH/SEQUENCE1.5T and 3T, T1-weighted turbo spin echo. ASSESSMENTRF heating was measured at tips of DBS leads implanted in brain-mimicking gel. STATISTICAL TESTSNone. RESULTSWe observed substantial fluctuation in RF heating mainly affected by phantom composition and DBS lead configuration, ranging from 0.14{degrees}C to 23.73{degrees}C at 1.5 T, and from 0.10{degrees}C to 7.39{degrees}C at 3T. The presence of subcutaneous fat substantially altered RF heating at electrode tips (-3.06{degrees}C < {Delta}T < 19.05{degrees}C). Introducing concentric loops in the extracranial portion of the lead at the surgical burr hole reduced RF heating by up to 89% at 1.5T and up to 98% at 3T compared to worst case heating scenarios. DATA CONCLUSIONDevice configuration and patient body composition significantly altered the RF heating of DBS leads during MRI at 1.5T and 3T. Interestingly, certain lead trajectories consistently reduced RF heating and image artifact over different imaging landmarks, RF frequencies, and phantom compositions. Such trajectories could be implemented in patients with minimal disruption to the surgical workflow.