Volumetric navigated MEGA‐SPECIAL for real‐time motion and shim corrected GABA editing |
| |
| Authors: | Muhammad G Saleh A Alhamud Jamie Near André J W van der Kouwe Ernesta M Meintjes |
| |
| Institution: | 1. Department of Human Biology, MRC/UCT Medical Imaging Research Unit, University of Cape Town, Cape Town, Western Cape, South Africa;2. Douglas Mental Health University Institute and Department of Psychiatry, McGill University, Montreal, Canada;3. Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Massachusetts, United States |
| |
| Abstract: | Mescher–Garwood (MEGA) editing with spin echo full intensity acquired localization (MEGA‐SPECIAL, MSpc) is a technique to acquire γ‐aminobutyric acid (GABA) without macromolecule (MM) contamination at a TE of 68 ms. However, due to the requirement of multiple shot‐localization, it is often susceptible to subject motion and B0 inhomogeneity. A method is presented for real‐time shim and motion correction (ShMoCo) using volumetric navigators to correct for motion and motion‐related B0 inhomogeneity during MSpc acquisition. A phantom experiment demonstrates that ShMoCo restores the GABA peak and improves spectral quality in the presence of motion and zero‐ and first‐order shim changes. The ShMoCo scans were validated in three subjects who performed up–down and left–right head rotations. Qualitative assessment of these scans indicates effective reduction of subtraction artefacts and well edited GABA peaks, while quantitative analysis indicates superior fitting and spectral quality relative to scans with no correction. Copyright © 2015 John Wiley & Sons, Ltd. |
| |
| Keywords: | GABA MEGA‐SPECIAL edited spectrum prospective correction real‐time motion correction real‐time shim correction zero‐order shim term first‐order shim term |
|
|
