Persistent T1 hypointensity as an MRI marker for treatment efficacy in multiple sclerosis

BackgroundMRI is often used as primary outcome measure in phase II clinical trials in multiple sclerosis (MS). Since persistent T1 hypointense lesions are a surrogate parameter for axonal damage and demyelination, they may serve as a marker for monitoring the efficacy of neuroprotective drugs. At present, a power analysis using black hole (BH) evolution as primary outcome measure has not been performed.ObjectiveTo assess the feasibility of using BH evolution on serial brain MR images as primary outcome measure in proof of concept studies in MS.MethodsMRI-data obtained from 169 active RRMS patients were analysed for BH evolution by determining the cumulative number of contrast enhancing lesions (CEL) evolving into a persistent black hole (PBH) after 3 months. With a parametric simulation procedure, based on a statistical distribution fitting the data, sample sizes were calculated.Results21.2% of the total number of CELs observed during the study period evolved into a PBH. Ring enhancing lesions evolved mos...