Three-dimensional fast fluid attenuated inversion recovery (3D fast FLAIR): a new MRI sequence which increases the detectable cerebral lesion load in multiple sclerosis.

Two-dimensional (2D) fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging is superior to T2 weighted conventional spin echo (CSE), in certain areas of the brain but not in others, in detecting the lesions of multiple sclerosis (MS). The present study evaluates the ability of a recently developed three-dimensional fast FLAIR (3D fast FLAIR) sequence in detecting and quantifying the brain lesions of multiple sclerosis. The lesion volumes measured on the 3D fast FLAIR sequence with 1.5 mm thick slices were compared with those obtained from CSE brain images with 5 mm thick slices. The findings seen in 3D fast FLAIR brain images in 10 normal control subjects are also described. 3D fast FLAIR images showed an overall increase of 34% in lesion volume compared with CSE. The increase was most marked in the periventricular and "discrete" areas of the cerebral hemispheres. Lesion volumes seen in the subcortical areas were similar in both sequences. The CSE images displayed higher lesion volumes in the posterior cranial fossa. It is concluded that 3D fast FLAIR is a promising technique for quantifying cerebral pathology in MS which is not accessible to 2D CSE.