Optimized T1-MPRAGE Sequence for Better Visualization of Spinal Cord Multiple Sclerosis Lesions at 3T

Abstract

Spinal cord lesions are highly prevalent in MS, and their visualization can help both in diagnosis and patient follow-up. However, the sensitivity of MR imaging to spinal cord lesions remains poor, primarily because of suboptimal contrast between lesions and a normal-appearing cord. Here, we propose an optimized 3D MPRAGE sequence for improved detection of MS lesions in the spinal cord at 3T. Images were acquired by use of T2 FSE, STIR, T1-gradient recalled-echo (for T1 mapping), and T1-MPRAGE in the sagittal plane, and T2*-weighted scans in the axial plane, on 40 patients with MS and 7 healthy volunteers. Two observers qualitatively evaluated the images for lesion conspicuity. Lesions seen between the C1 and C4 segments in 10 randomly selected patients with MS were further evaluated quantitatively for contrast-to-noise ratio between the lesion and normal-appearing cord, and for lesion burden. Spinal cord lesions were more conspicuous on the optimized T1-MPRAGE sequence than on any other sequence tested. Detailed analysis revealed that lesions were almost 3 times more conspicuous (P < .01), and the total lesion volume was 2 times greater (P < .05, n=10), in the T1-MPRAGE sequence compared with the standard STIR sequence. Correlation of clinical disability (Expanded Disability Status Score) with lesion load from each sequence also demonstrated the importance of the improved lesion conspicuity with T1-MPRAGE. The optimized T1-MPRAGE sequence described here improves the reliability of lesion visualization and estimation of lesion burden, especially when used in conjunction with other well-established clinical sequences.