THE INFLUENCE OF SLICE ORIENTATION ON BRAIN MRI LESION LOAD MEASUREMENT IN MULTIPLE-SCLEROSIS

This study aimed at evaluating the influence of a different slice orie ntation on brain magnetic resonance imaging (MRI) lesion load in multi ple sclerosis (MS). Fifteen MS patients were scanned obtaining both ax ial and sagittal conventional spin echo (24 slices; TR 2400, TE 30/80) brain MRI. The total lesion load (TLL) was assessed twice for each sc an, using a semi-automated local thresholding technique and the some m arked hardcopies. The mean TLL was 22734 mm(3) for axial and 22003 mm( 3) for sagittal scans. The mean intra-observer coefficient of variatio n (COV) was 4.65% for the axial acquisitions and 4.52% for the sagitta l acquisitions. This difference was not statistically significant (one -way ANOVA, P > 0.1). The lesion load was significantly higher from ax ial MRI as compared to the intro-observer variability (two-way ANOVA, P = 0.01), but the fluctuations around this average difference between axial and sagittal scan TLL were significantly large (test for intera ction, P < 0.001). Our data indicate that the use of sagittal conventi onal MRI scans does not seem to be worthwhile for the quantitative ass essment of lesion load in MS patients.