Aim: Using baseline data from a clinical trial of domagrozumab in Duchenne 
muscular dystrophy, we evaluated the correlation between functional measures and 
quantitative MRI assessments of thigh muscle. Patients & methods: Analysis 
included timed functional tests, knee extension/strength and North 
Star Ambulatory Assessment. Patients (n = 120) underwent examinations of one 
thigh, with MRI sequences to enable measurements of muscle volume (MV), MV 
index, mean T2 relaxation time via T2-mapping and fat fraction. Results: MV was 
moderately correlated with strength assessments. MV index, fat fraction and 
T2-mapping measures had moderate correlations (r ∼ 0.5) to all functional tests, 
North Star Ambulatory Assessment and age. Conclusion: The moderate correlation 
between functional tests, age and baseline MRI measures supports MRI as a 
biomarker in Duchenne muscular dystrophy clinical trials. Trial registration: 
ClinicalTrials.gov, NCT02310763; registered 4 November 2014.