Optimization of Reconstruction Parameters of Compressed Sensing STIR SEMAC for Metal Artifact Reduction MRI of Hip, Knee and Ankle Arthroplasty Implants: How many Iterations and how much Regularization is needed?

Compressed sensing-(CS)-based Slice Encoding for Metal Artifact Correction (SEMAC) turbo spin echo (TSE) pulse sequences achieve high–quality metal artifact reduction MRI around arthroplasty implants. Compressed sensing-based undersampling of k-space permits the time-neutral use of SEMAC, but requires iterative reconstruction algorithms, which are time consuming. We determined minimum number of iterations and regularization required for diagnostic image quality of STIR CS-SEMAC data sets of hip, knee and ankle arthroplasty implants. Our results show that 15-17 iterations and 0.0035 regularization results in optimal image quality of STIR CS-SEMAC images, which currently requires 4-5 minutes of reconstruction time.