2008 Volume 54 Issue 2 Pages 158-165
Purpose: This study evaluated the incidence of MR findings showing a hyperintensity rim surrounding multiple sclerosis (MS) plaque on T1-weighted images using image analysis software. We also evaluate the efficacy of this MR finding for differentiating between MS and lacunar infarction. Subject and Method: We reviewed T1-weighted images in clinically diagnosed MS patients who underwent MR imaging between February 2006 and July 2007. Two hundred and thirtynine nodular low signal intensities over 5mm in minimal diameter were observed in 39 MS patients. To compare the incidence of MR findings, we also reviewed T1-weighted images in randomly selected lacunar infarction patients who underwent MR imaging during the same period. There were 51 nodular low signal intensities over 5mm in shortest diameter in 34 lacunar infarction patients. After standardization of MR images, we calculated each signal intensity at the plaque margin (M.I.) and surrounding white matter (Wh.I.) using plot-profile analysis. We judged that hyperintensity rim sign was positive when the M.I/ Wh.I. ratio was over 1.05. Results: Among 239 T1 low intensity plaques in 39 MS patients, hyperintensity rim sign was positive for 81 (33.9 %) plaques in 21 (53.8 %) patients. Among 51 T1 low intensity lesions in 34 lacunar infarction patients, hyperintensity rim sign was positive for only one lesion in one patient. There were significant differences in the incidence of hyperintensity rim sign between the two patients groups (p<0.0001). Conclusion: On quantitative analysis using imaging standardization and plot-profile analysis, hyperintensity rim sign was observed in one-third of T1 low intensity MS plaques. This finding seems to be useful to differentiate multiple sclerosis from lacunar infarction.
