A LONGITUDINAL BRAIN MRI STUDY COMPARING THE SENSITIVITIES OF THE CONVENTIONAL AND A NEWER APPROACH FOR DETECTING ACTIVE LESIONS IN MULTIPLE-SCLEROSIS

Monthly dual-echo spin-echo (SE) and enhanced magnetic resonance imagi ng (MRI) after the injection of a standard dose (SD) of gadolinium (Gd ) is the conventional approach to monitor short-term disease activity in multiple sclerosis (MS). In this study, the sensitivity of this app roach in detecting active lesions in MS was compared with that of mont hly fast fluid attenuated inversion recovery (FLAIR) scans associated with enhanced MRI after the injection of a triple dose (TD) of Gd. Thi rteen patients with relapsing-remitting MS entered the study. Monthly MRI scans were obtained on four occasions in two separate sessions (in terval between 12 and 24 h). In one session, dual-echo conventional SE and SD T1-weighted scans were obtained; in the other, fast-FLAIR and TD T1-weighted scans. The order of the two sessions was randomized. Th ree observers counted the numbers of active lesions detected by each o f the two approaches. One hundred and four active lesions were detecte d by the conventional approach and 199 by the newer approach (average increase per patient=75%, range=0-325%). The mean number of active les ions per month per patient was 2.0 for the conventional approach and 3 .8 for the new approach (P=0.004). Scans with active lesions were 34/5 2 (65%) with the conventional approach and 37/52 (71%) with the new ap proach. Our data indicate that the combined use of monthly fast-FLAIR and TD enhanced T1-weighted scans increases the number of active lesio ns detected on serial MRT scans from patients with MS. (C) 1998 Elsevi er Science B.V. All rights reserved.