Evoluzione delle lesioni demielinizzanti mediante esami seriati di RM

Aim of the study was to monitor the natural history of new demyelinating lesions by means of serial Magnetic Resonance Imaging (MRI). Sixty-eight relapsing-remitting multiple sclerosis (MS) patients were monthly examined by enhanced T1 weighted and T2 weighted SpinEcho images. New enhancing lesions, which were not present on the first scan, were considered as starting point. Then after the evolution of these lesions were followed for five monthly scans. Out of the 63 new enhancing lesions, 26 (40%) showed persisting enhancement at 1-month scan, and 12 (19%) at 2-month scan; 4 (6%) lesions presented a fluctuating recurrent enhancement during the follow-up. All 63 new enhancing lesions had a corresponding area of abnormality on 72 weighted images. At first follow-up scan 62 (98%) and 21 (33%) of the new enhancing lesions were seen as T2 hyperintensity and T1 hypointensity respectively. At the last follow-up scan, T2 hyperintensity was observed in 58 (92%) of the new enhancing lesions, and T1 hypointensity in 26 (41%) of them. Five (8%) of the new enhancing lesions disappeared at the last scan in both T2 and T1 weighted images. This study documents that the evolution of new enhancing lesions is related to the different phases of demyelinating process.