The SENSE ghost: Field-of-view restrictions for SENSE imaging

Purpose: To describe a known (but undocumented) limitation in parallel imaging using simulation and experiment. This limitation consists of an artifact that appears when the imaging field of view (FOV) is less than the object size. This study demonstrates this artifact in the phase- and partition-encoding dimensions. Materials and Methods: One-dimensional simulations as well as in vivo experiments were performed with FOVs greater and less than the object being imaged. Full-FOV, reduced-FOV, and SENSE reconstructions were visually compared. Results: Image artifacts occurred when the final SENSE FOV was smaller than the object being imaged. This artifact, termed the SENSE ghost, was a residual fold-over/ aliasing artifact. Its location was in the central portion of the image rather than at the edges of the image. Conclusion: This image artifact results from an FOV being smaller than the imaged object. The SENSE reconstruction cannot unfold this additional fold-over, and will place it in a predictable image location based on the SENSE reduction factor. Knowledge of this artifact is necessary when prescribing SENSE acquisitions and interpreting the resulting images. (C) 2004 Wiley-Liss, Inc.