Comparison of Multiple Sclerosis Lesions at 1.5 and 3.0 Tesla

OBJECTIVE: To evaluate the relative sensitivity of MR scanning for multiple sclerosis (MS) at 1.5 Tesla (T) and 3.0 T using identical acquisition conditions, as is typical of multicenter clinical trials. METHODS: Twenty-five subjects with MS were scanned at 1.5 T and 3.0 T using fast spin echo, and T(1)-weighted SPGR with and without gadolinium contrast injections. Image data, blinded to field strength, were analyzed using automated segmentation and lesion counting. RESULTS: Relative to scanning at 1.5 T, the 3.0 T scans showed a 21% increase in the number of detected contrast enhancing lesions, a 30% increase in enhancing lesion volume and a 10% increase in total lesion volume. DISCUSSION: The improved detection ability using high-field MR imaging is prominent even when sequence parameters are optimized around the midfield units. Multicenter trials using both 1.5 T and 3.0 T instruments may be affected by these sensitivity differences.