What is the Relevance of the Systematic Use of Gadolinium During the MRI Follow-Up of Multiple Sclerosis Patients Under Natalizumab?

Background Multiple sclerosis (MS) patients represent a population potentially affected by the intracerebral accumulation of gadolinium-based contrast agents (GBCA) due to repeated magnetic resonance imaging (MRI) performed during their lifetime; however, MRI is still the best tool to monitor MS inflammatory activity. Objective This study aimed to evaluate the relevance of GBCA injections during the MRI follow-up of MS patients under natalizumab (Tysabri) treatment. Methods The MRI data results were retrospectively reviewed in a monocentric study (University Hospital of Toulouse, France) from all consecutive patients treated with natalizumab from January 2014 to January 2017. For each examination during the whole MRI follow-up, new lesions (enhancing and non-enhancing) were analyzed. Results A total of 129 patients were included in this study (65% female, mean age = 41 years, mean treatment duration 6.5 years, 50% positive for John Cunningham virus) and benefited from 735 MRIs with GBCA. Only 3 MRIs showed a new enhancing lesion, systematically encountered after treatment discontinuation. Conclusion According to this study based on the clinical and radiological practice, the systematic use of GBCA seems of limited relevance in the MRI follow-up of asymptomatic patients treated continuously with natalizumab.