Age-related T2 changes in hindlimb muscles of mdx mice.

Abstract

Magnetic resonance imaging (MRI) was used to monitor changes in the transverse relaxation time constant (T2) in lower hindlimb muscles of mdx mice at different ages. Young (5 weeks), adult (44 weeks), and old mdx (96 weeks), and age-matched control mice were studied. Young mdx mice were imaged longitudinally, whereas adult and old mdx mice were imaged at a single time-point. Mean muscle T2 and percent of pixels with elevated T2 were significantly different between mdx and control mice at all ages. In young mdx mice, mean muscle T2 peaked at 7-8 weeks and declined at 9-11 weeks. In old mdx mice, mean muscle T2 was decreased compared with young and adult mice, which could be attributed to fibrosis. MRI captured longitudinal changes in skeletal muscle integrity of mdx mice. This information will be valuable for pre-clinical testing of potential therapeutic interventions for muscular dystrophy.