Accelerating Sequences in the Presence of Metal by Exploiting the Spatial Distribution of Off-Resonance

Matthew R. Smith¹, Nathan S. Artz¹, Kevin M. Koch², Scott B. Reeder¹, ³

To successfully image near metallic implants, multiple independent acquisitions are often required at different RF offsets and combined. This dramatically increases scan time. However, each frequency bin contains unique spatial information that is analogous to the spatial sensitivity of multi-channel receiver coils. We demonstrate that this behavior can be exploited to accelerate k-space encoding using a reconstruction similar to parallel imaging. This work demonstrates feasibility of acceleration using a femoral stem of a titanium hip implant in a phantom. Independent acquisition of each off-resonance bin provides a distinct advantage to optimize acceleration by enabling off-resonance dependent reduction factors.