Improved fat suppression using multipeak reconstruction for IDEAL chemical shift fat-water separation: Application with fast spin echo imaging

Abstract

Purpose: To evaluate and quantify improvements in the quality of fat suppression for fast spin-echo imaging of the knee using multipeak fat spectral modeling and IDEAL fat-water separation. Materials and Methods: T 1-weighted and T 2-weighted fast spin-echo sequences with IDEAL fat-water separation and two frequency-selective fat-saturation methods (fat-selective saturation and fat-selective partial inversion) were performed on 10 knees of five asymptomatic volunteers. The IDEAL images were reconstructed using a conventional single-peak method and precalibrated and self-calibrated multipeak methods that more accurately model the NMR spectrum of fat. The signal-to-noise ratio ISNR) was measured in various tissues for all sequences. Student t-tests were used to compare SNR values. Results: Precalibrated and self-calibrated multipeak IDEAL had significantly greater suppression of signal (P < 0.05) within subcutaneous fat and bone marrow than fat- selective saturation, fat-selective partial inversion, and single-peak IDEAL for both T 1-weighted and T 2-weighted fast spin-echo sequences. For T 1-weighted fast spin-echo sequences, the improvement in the suppression of signal within subcutaneous fat and bone marrow for multipeak IDEAL ranged between 65% when compared to fat-selective partial inversion to 86% when compared to fat-selective- saturation. For T2-weighted fast spin-echo sequences, the improvement for multipeak IDEAL ranged between 21% when compared to fat-selective partial inversion to 81% when compared to fat-selective saturation. Conclusion: Multipeak IDEAL fat-water separation provides improved fat suppression for T 1-weighted and T 2- weighted fast spin-echo imaging of the knee when compared to single-peak IDEAL and two widely used frequency- selected fat-saturation methods. © 2009 Wiley-Liss, Inc.