Experimental Assessment of Skin-Bore Contact Heating during Magnetic Resonance Imaging

Motivation: There's an increasing concern with skin-bore contact heating during MRI examination, however the underlying mechanism and risk-influencing factors are still poorly understood. Goal(s): To develop an experimental method to characterize local SAR at skin-bore contact points. Approach: In this study, both simulations as well as phantom measurements were performed to identify potential mechanisms. Results: Peak heating levels were observed at around the endrings of the birdcage model, which were confirmed in experimental data. A maximum local SAR of 40.2 W/kg was measured at the tip of the phantom. Impact: Although the observed levels did not exceed regulatory limits on extremity SAR, increased local SAR levels were observed at longitudinal locations along the bore wall that correspond to the high levels of conservative electric field around the bircage endrings.