A comparison of the sensitivity of MRI after double- and triple-dose Cd-DTPA for detecting enhancing lesions in multiple sclerosis

We compared the number and volume of enhancing lesions detected in patients with multiple sclerosis (MS) seen on post-contrast T-1-weighted scans obta ined after the injection of different gadolinium-DTPA (Gd) doses. Enhanced magnetic resonance imaging (MRI) scans were obtained from 16 patients with relapsing remitting or secondary progressive MS on two different occasions separated by an interval of approximately 24 h. On the first occasion, enha nced scans were obtained 15 min after the injection of a double dose of Gd (0.2 mmol/Kg), on the second 15 min after the injection of a triple dose (0 .3 mmol/Kg) of Gd. Scans were assessed by consensus in a random order by tw o observers unaware of the dose of Gd used. We counted the same 30 enhancin g lesions on both double dose and triple dose scans from 9 patients. The me an (SD) volumes of enhancing lesions were 1.7 (2.7) mL on double dose and 1 .9 (3.4) mt on triple-dose scans. This difference was not statistically sig nificant. This study demonstrated that double dose of Gd has a sensitivity for detecting MS activity similar to that of a triple dose, with the advant age of a significant cost saving. (C) 2000 Elsevier Science Inc. All rights reserved.