3D MRI in multiple sclerosis: a study of three sequences at 3 T

Abstract

The objective of this study was to assess the feasibility of using 3D acquisition at 3 T for imaging patients with multiple sclerosis (MS). Feasibility was assessed by three criteria based on acquisition time, specific absorption rate (SAR) and image quality. 47 patients with clinically definite MS underwent imaging in a Siemens 3T Trio MR scanner. Patient safety data were obtained following the scan sessions. The study had local ethics approval. The following three-dimensional (3D) sequences, all acquired coronally, were used: T2 fluid attenuated inversion recovery (FLAIR) (repetition time (TR) 6000 ms, echo time (TE) 353 ms, inversion time (TI) 2200 ms), 0.5x0.5x1 mm voxels, acquisition time 10 min 38 s; T2 turbo spin echo (TSE) (TR 3000 ms, TE 354 ms), 1x1x1 mm voxels, acquisition time 8 min 29 s; T1 inversion recovery (IR) (TR 2040 ms, TE 5.56 ms, TI 1100 ms), matrix 512x448 (0.5x0.5 mm pixels), 0.5x0.5x1 mm voxels, acquisition time 7 min 38 s. Total acquisition time was 26 min 45 s. Example images are presented. 3D scanning at 3 T provides highly detailed, high quality images with acquisition times tolerated by MS patients, even by those with severe disability. The volumetric data are suitable for a wide variety of post-processing techniques; the authors suggest that 3D studies at 3 T should be considered as the possible brain imaging protocol for either cross-sectional or longitudinal studies in MS and that the 3D T2 FLAIR sequence should be considered for the purposes of radiological diagnosis.