Correcting bSSFP Distortion Near Metals with Geometric Solution Phase

Michael Nicholas Hoff¹, Qing-San Xiang¹, ²

Balanced steady state free precession imaging can suffer from geometric distortion near metals. The geometric solution (GS) for banding correction has phase which maps the local field inhomogeneity; here this phase is unwrapped and used to remap distorted signal in the GS magnitude image. This distortion correction did not require a phase reference due to the insignificance of phase error relative to the off-resonant phase accumulation near the metal, and the unwrapping algorithm proved robust in all signal regions. The advantage of this correction is that it does not require excess scan time beyond that needed to compute the GS.