FAST SPIN-ECHO AND FAST FLUID-ATTENUATED INVERSION-RECOVERY VERSUS CONVENTIONAL SPIN-ECHO SEQUENCES FOR MR QUANTIFICATION OF MULTIPLE-SCLEROSIS LESIONS

PURPOSE: To compare fast spin-echo (FSE) and fast fluid-attenuated inv ersion recovery (FLAIR) sequences with conventional spin-echo (CSE) MR imaging in the quantification of the number and volume of multiple sc lerosis lesions. METHODS: In 30 patients with relapsing-remitting mult iple sclerosis, we calculated the total number and volume of lesions d etected with each of the three sequences using a semiautomated program . RESULTS: On CSE sequences, we calculated a total of 2583 lesions wit h a global volume of 836.3 cm(3). With FSE sequences, we observed a 16 % relative reduction in the number of lesions detected and a 25% relat ive reduction in global volume as compared with CSE. With fast FLAIR s equences, we detected a significantly lower number and volume of infra tentorial lesions, whereas at the cortical/subcortical level the lesio ns were both more numerous and bulkier than on CSE sequences. Finally, we observed a higher lesion/white matter contrast, a significant redu ction in time required for the quantification of lesion load, and a ve ry low interobserver variability in favor of fast FLAIR sequences. CON CLUSION: Despite its limitations in the detection of infratentorial le sions, the fast FLAIR sequence in conjunction with a semiautomated qua ntification program provides a reliable means to evaluate the total le sion burden in patients with MS.