Blood-brain barrier impairment in acute optic neuritis evaluated by Gadolinium-DTPA enhanced MRI and CSF studies

We prospectively compared the brain magnetic resonance imagings (MRIs) following Gadolinium-DTPA (Gd-DTPA) injection with unenhanced T-2-weighted MRIs in a well-defined population-based group of 76 patients aged 20-57 years with acute optic neuritis (ON). We aimed to evaluate the blood-brain barrier impairment in ON and the interrelationships of findings by CSF analyses and MRI. Lumbar puncture and MRI were performed within a median of 19 and 13 days from onset respectively. MRI showed unenhanced lesions in 22 of 54 patients with monosymptomatic ON (AMON) compared to 19 of 22 patients with ON as part of clinically definite MS (CDMS) (p = 0.0002). Enhanced lesions (sized 2-38 mm) were revealed in 10 out of 54 patients with AMON vs 8 of 22 patients with CDMS (p = 0.06). The number of enhancing lesions in proportion to the number of unenhancing lesions was higher in patients with AMON than in patients with CDMS (p < 0.05). Ten of altogether 30 enhancing lesions were situated periventricularly. An impaired blood-brain barrier judged by increased albumin quotient was found in only five patients. The patients with AMON often had significantly less abnormal intrathecal IgG synthesis (p = 0.02), IgG-index (p = 0.02) and oligoclonal bands (p = 0.04) than did the patients with CDMS. In AMON, the presence of oligoclonal bands was significantly related to abnormal unenhanced and enhanced MRI, p = 0.01 and p = 0.02, respectively, No other significant relationships were observed between the results of MRI and CSF findings, neither in AMON nor in CDMS.