Postsurgical Spinal Magnetic Resonance Imaging With Iterative Decomposition of Water and Fat With Echo Asymmetry and Least-Squares Estimation

Objective: Magnetic resonance imaging (MRI) is the most popular follow-up study for patients who have undergone spinal surgery. However, the image quality often becomes poor because of artifacts from metal implants and/or from failed fat suppression, which obscure diagnosis. Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) is a new fat suppression method that is less affected by inhomogeneity of the magnetic field. Here, we compared postsurgical spinal MRI with IDEAL versus chemical shift selective saturation (CHESS). Methods: For 35 patients who had spinal surgery, we examined T2-weighted fast spin-echo sagittal images of the spine with both IDEAL and CHESS. Two radiologists evaluated the degrees of fat suppression and spinal canal projection from 0 (least/worst) to 2 (most/best). Results: Fat suppression and spinal canal scores for IDEAL were statistically higher than those for CHESS (P < 0.05). Conclusions: Iterative decomposition of water and fat with echo asymmetry and least-squares estimation is clinically useful for postoperative spinal MRI.