A COMPARISON BETWEEN THE SENSITIVITIES OF 3-MM AND 5-MM THICK SERIAL BRAIN MRI FOR DETECTING LESION VOLUME CHANGES IN PATIENTS WITH MULTIPLE-SCLEROSIS

In this longitudinal study the authors evaluated the sensitivity of 3- mm and 5-mm magnetic resonance imaging (MRI) of the brain in the detec tion of lesion load changes over time in multiple sclerosis (MS). The authors also correlated the changes detected with these two techniques with the changes in disability. Eighteen patients with MS underwent t wo MRI examinations of the brain-one at entrance into the study and on e follow-up examination. At both sessions, images with 24 contiguous s lices 5 mm thick and another with 40 contiguous axial slices 3 mm thic k were consecutively acquired. On the same occasions, the patients' Ex panded Disability Status Scale (EDSS) scores were rated. MR images wit h slices 3 mm thick showed higher lesion loads than those with slices 5 mm thick at both entrance and follow-up examinations (median, 13.4 v s 12.8 ml and 17.5 vs 17.0 ml, respectively; p < 0.0001). The correlat ion between MRI and EDSS changes was significant for both MRI acquisit ion schemes (3 mm, r = 0.64; 5 mm, r = 0.59). The data suggest that ac quisition of thinner slices does not significantly increase the sensit ivity of MRI of the brain in the detection of lesion load changes in M S.