319P MRI gluteal/thigh muscle fat fraction detects NSAD motor task failures in men with Becker muscular dystrophy

• Published in: Neuromuscular disorders : NMD 2024-10, Vol.43, p.104441, Article 104441.650
• Main Authors: Rock, K., Willcocks, R., Barnard, A., Forbes, S., Lott, D., Senesac, C., Rooney, W., Baetscher, E., Subramony, S., Chahin, N., Kamal, O., Hinkle, J., Corwine, A., Huerta, O., Walter, G., Vandenborne, K.
• Format: Article
• Language: English
• ISSN: 0960-8966
• DOI: 10.1016/j.nmd.2024.07.659

Becker muscular dystrophy (BMD) results in fat replacement of skeletal muscle and impaired functional performance. Quantitative magnetic resonance (qMR) imaging of muscle fat fraction (FF) has been used as a biomarker of muscle deterioration in muscular dystrophies. Specifically, qMR whole-body imaging (WBI) can quickly analyze multiple muscles and develop FF composites. The North Star Assessment for limb-girdle type muscular dystrophies (NSAD), has the potential to assess motor function in men with BMD across a wide range of abilities. Thus, we aimed to 1) assess the relationship between qMR FF and NSAD scores, and 2) determine qMR FF cut-off values for loss of performance on NSAD tasks that require gluteal and thigh muscle contractions. 41 men with BMD (18-62 years) completed 3-point Dixon qMR WBI and the NSAD. GlutThigh was calculated as the average FF of the right gluteus maximus, gluteus medius/minimus, quadriceps femoris, and hamstrings. The relationship between GlutThigh and function was assessed using Spearman's rho. GlutThigh cut-off values to discriminate men able or unable to perform each NSAD task were calculated using the receiver operating characteristic (ROC) and the Youden Index. Men with BMD had GlutThigh values from 0.08-0.89 (median: 0.58). Higher GlutThigh was strongly associated with lower NSAD scores (rho=-0.93; p