Interscanner Variation in Brain MR Lesion Load Measurements in Multiple Sclerosis Using Conventional Spin-Echo, Rapid Relaxation-Enhanced, and

BACKGROUND AND PURPOSE: Different MR pulse sequences have been proposed for measuring multiple sclerosis (MS)-related abnormalities. The reproducibility of measured brain MS lesion volumes was compared for MR images performed using different scanners and different pulse sequences. METHODS: Nine patients with relapsing-remitting MS were each imaged on two scanners and, on each occasion, dual-echo conventional spin-echo, dual-echo rapid-acquisition relaxa-tion-enhanced (RARE), and fast fluid-attenuated inversion recovery (fast-FLAIR) images were obtained. The lesion volume present on each image was evaluated three times by a single observer in random order, using a local thresholding technique. RESULTS: The mean lesion volumes present on fast-FLAIR images were significantly higher than those measured on dual-echo conventional spin-echo and RARE images. The mean in-traobserver coefficients of variation for the different sequences and scanners ranged from 3.0% to 4.2 % (no statistically significant difference). For each of the sequences, the use of different scanners introduced a variability that was higher than the intraobserver variability: the inter-scanner coefficient of variation was 7.4 % for conventional spin-echo, 9.5 % for RARE, an