On the Reproducibility of Direct Signal Control with Variable Excitation and Refocusing (DiSCoVER) for TSE Shoulder MRI at 7T

Motivation: Turbo Spin Echo (TSE) imaging is clinically of high importance for high-resolution musculoskeletal MRI. Direct signal control is a promising technique to improve image quality at ultrahigh fields. Goal(s): Reproducibility test of the TSE-DiSCoVER sequence for 7T shoulder MRI. Approach: Four subjects were repeatedly scanned 5 times without repositioning but with renewing the RF shimming procedure for each run. Coefficients of variation were calculated for different regions of interest. Results: Reproducibility was acceptable for subcutaneous fat suppression and muscle infraspinatus signal consistency. However, unacceptably high variations were observed for head of humerus, scapula, glenoid labrum, and most pronounced in the muscle subscapularis. Impact: Clinically acceptable reproducibility of currently implemented TSE-DiSCoVER was not achieved over the full transversal cross-section. Renewing the RF shimming procedure can improve image quality, even across the whole slice. A need for improvements in underlying B1+-mapping and postprocessing is shown.