MRI lesion volume measurement in multiple sclerosis and its correlation with disability: a comparison of fast fluid attenuated inversion recovery (fFLAIR) and spin echo sequences.

OBJECTIVES To assess whether multiple sclerosis lesion volume measurements derived using the fast fluid attenuated inversion recovery (fFLAIR) sequence show better reproducibility or correlation with disability than those derived using the conventional spin echo (CSE) sequence. METHODS Part I: twenty five patients with multiple sclerosis were scanned with CSE, fast spin echo (FSE), and fFLAIR. Lesion volume was determined twice for each sequence using a local threshold segmentation technique. Part II: fifty six patients with multiple sclerosis were scanned with CSE and fFLAIR. Total and regional brain lesion volumes were compared with the Kurtzke extended disability scale (EDSS) and functional systems scores (FSS). RESULTS Part I: analysis times were significantly longer for CSE than for FSE or fFLAIR. There was no significant difference in the reproducibility of the three sequences. Part II: total lesion volumes were similar but posterior fossa lesion volumes were significantly greater for CSE and subcortical lesion volumes significantly greater for fFLAIR. There was a significant correlation between total volume and EDSS with both sequences (CSE r=0.49; fFLAIR r=0.44). Correlations for the two sequences showed minor differences when anatomical region and FSS were considered separately. CONCLUSIONS CSE, FSE, and fFLAIR are equally reproducible; FSE yields lower volumes than CSE; fFLAIR gives similar volumes to CSE but underscores the posterior fossa. Overall clinical correlations are similar for CSE and fFLAIR.