Sensitivity of delayed gadolinium-enhanced MRI in multiple sclerosis

Introduction - We performed this study to define the sensitivity of delayed gadolinium-enhanced magnetic resonance imaging (MRI) in detecting active lesions in the brains of patients with multiple sclerosis (MS). Material and methods - T₁-weighted images were obtained in 27 patients with relapsing-remitting or secondary progressive MS before, 5-7 min and 20-30 min after the injection of 0.1 mmol/kg gadolinium-DTPA. Results - One-hundred- and-three enhancing lesions were found on the early and 110 on the delayed scans (increase = 6.4%). Six patients had 8 additional lesions in the delayed scans, while 1 patient had 1 more lesion on the early scan. Two of the 12 (17%) patients with no enhancing lesions on the early scans had 2 enhancing lesions on the delayed scans. The average increase of enhancing lesion detection with delayed scanning was 14.5% for those patients who already had enhancing lesions on the early post-contrast scans. A significant increase of the enhancing lesion volume was found with delayed scanning (P = 0.004). Conclusion - These data indicate that it is possible to increase MRI sensitivity in detecting MS active lesions by delaying the scanning after gadolinium injection.