Investigating the quantitative fidelity of prospectively undersampled chemical shift imaging in muscular dystrophy with compressed sensing and parallel imaging reconstruction

Abstract

Fat fraction measurement in muscular dystrophy has an important role to play in future therapy trials. Undersampled data acquisition reconstructed by combined compressed sensing and parallel imaging (CS-PI) can potentially reduce trial cost and improve compliance. These benefits are only gained from prospectively undersampled acquisitions. Eight patients with Becker muscular dystrophy were recruited and prospectively undersampled data at ratios of 3.65×, 4.94×, and 6.42× were acquired in addition to fully sampled data: equivalent coherent undersamplings were acquired for reconstruction with parallel imaging alone (PI). Fat fraction maps and maps of total signal were created using a combined compressed sensing/parallel imaging (CS-PI) reconstruction. The CS-PI reconstructions are of sufficient quality to allow muscle delineation at 3.65× and 4.94× undersampling but some muscles were obscured at 6.42×. When plotted against the fat fractions derived from fully sampled data, non-significant bias and 95% limits of agreement of 1.58%, 2.17% and 2.41% were found for the three CS-PI reconstructions, while a 3.36× PI reconstruction yields 2.78%, 1.8 times worse than the equivalent CS-PI reconstruction. Prospective undersampling and CS-PI reconstruction of muscle fat fraction mapping can be used to accelerate muscle fat fraction measurement in muscular dystrophy.