MR Imaging After Spinal Fusion using Slice Encoding For Metal Artifact Correction (SEMAC)

Kathryn Jane Stevens¹, Pauline W. Worters¹, Garry Evan Gold¹, Jarrett K. Rosenberg¹, Brian A. Hargreaves¹

MRI of the lumbar spine is often of limited value in patients after instrumented spinal fusion due to the extensive associated metal artifact. Slice Encoding for Metal Artifact Correction (SEMAC) is an MRI technique that corrects for spatial distortions by performing extra slice encoding and using view-angle tilting. MRI in 8 patients with previous spinal fusions demonstrated significantly decreased in-plane and through-plane artifact on SEMAC images compared to 2D FSE. This allowed improved visualization of the spinal canal, spinal nerve roots and neural foramina, which we hope will translate to improved diagnostic capabilities in patients with failed back surgery syndrome.