MRI Near Metal Objects: Investigating the Effects of Induced RF Currents & Currents Induced by Gradient Switching on SE Phase Images using a Simple Model System

Hanne Wojtczyk¹, Petros Martirosian¹, Verena Ballweg¹, Hansjoerg Graf¹, Fritz Schick¹

In MRI near metals, electrical currents can be induced in the metals by RF pulses or by gradient switching (due to the imaging or concomitant gradient fields). The objective of the study was to systematically assess for the first time which effects both types of current have on SE phase images. A copper sheet was imaged in a coronal plane at 1.5 T using a SE sequence. The position of the sheet, phase encoding direction, bandwidth and transmit voltage were varied. For the measurements performed here, the SE phase images were dominated by effects from currents induced by gradient switching.