Residual Acceleration Ghost Artifacts in MP2RAGE at 7T MRI and Their Correction with BART Reconstruction

Motivation: Ghosting artifacts were observed on the INV2 contrast of MP2RAGE images obtained at 7T MRI using the standard scanner workflow with a parallel imaging factor of R=3x1. They could not be suppressed by changing the scan parameters. Goal(s): To determine the cause of and reduce ghosting in MP2RAGE with an offline reconstruction. Approach: Develop a pipeline for parallel imaging using BART including noise pre-whitening, coil compression, and ESPIRiT based reconstruction with Soft-SENSE. Results: The ghosting artifacts were identified as residual aliasing from the scanner's parallel imaging reconstruction, and they were suppressed by the offline reconstruction. Impact: MP2RAGE is the most popular sequence for T1-weighted imaging at 7T. The ghosting artifacts on the INV2 contrast were attributed to the parallel acceleration. Our solution may contribute to a revised reconstruction of the MP2RAGE sequence.