Quantifying disease activity in fatty-infiltrated skeletal muscle by IDEAL-CPMG in Duchenne muscular dystrophy.
The purpose of this study was to explore the use of iterative decomposition of water and fat with echo asymmetry and least-squares estimation Carr-Purcell-Meiboom-Gill (IDEAL-CPMG) to simultaneously measure skeletal muscle apparent fat fraction and water T2 (T2,w) in patients with Duchenne muscular dystrophy (DMD). In twenty healthy volunteer boys and thirteen subjects with DMD, thigh muscle apparent fat fraction was measured by Dixon and IDEAL-CPMG, with the IDEAL-CPMG also providing T2,w as a measure of muscle inflammatory activity. A subset of subjects with DMD was followed up during a 48-week clinical study. The study was in compliance with the Patient Privacy Act and approved by the Institutional Review Board. Apparent fat fraction in the thigh muscles of subjects with DMD was significantly increased compared to healthy volunteer boys (p <0.001). There was a strong correlation between Dixon and IDEAL-CPMG apparent fat fraction. Muscle T2,w measured by IDEAL-CPMG was independent of changes in apparent fat fraction. Muscle T2,w was higher in the biceps femoris and vastus lateralis muscles of subjects with DMD (p <0.05). There was a strong correlation (p <0.004) between apparent fat fraction in all thigh muscles and six-minute walk distance (6MWD) in subjects with DMD. IDEAL-CPMG allowed independent and simultaneous quantification of skeletal muscle fatty degeneration and disease activity in DMD. IDEAL-CPMG apparent fat fraction and T2,w may be useful as biomarkers in clinical trials of DMD as the technique disentangles two competing biological processes.
['Mankodi|Ami|A|', 'Bishop|Courtney A|CA|', 'Auh|Sungyoung|S|', 'Newbould|Rexford D|RD|', 'Fischbeck|Kenneth H|KH|', 'Janiczek|Robert L|RL|']
D000273:Adipose Tissue D000293:Adolescent D002648:Child D002675:Child, Preschool D004311:Double-Blind Method D005500:Follow-Up Studies D006801:Humans D007090:Image Interpretation, Computer-Assisted D016018:Least-Squares Analysis D016014:Linear Models D008279:Magnetic Resonance Imaging D008297:Male D018482:Muscle, Skeletal D020388:Muscular Dystrophy, Duchenne D009841:Oligonucleotides D013848:Thigh D016896:Treatment Outcome D000070857:Walk Test D016138:Walking
Skeletal muscle IDEAL-CPMG Duchenne muscular dystrophy Apparent fat fraction Fatty degeneration Magnetic resonance imaging T(2) relaxation times Water T(2)