SPECT Imaging of Muscle Injury with [(99m)Tc]MDP in a Mouse Model of Muscular Dystrophy

PURPOSE: Tc-99m methylene diphosphonate ([(99m)Tc]MDP) is an in vivo bone imaging agent that also accumulates in injured skeletal muscle cells. The objective of this study was to investigate if [(99m)Tc]MDP could be used to detect muscle injury in the mdx mouse model of Duchenne muscular dystrophy (DMD). PROCEDURES: Static whole-body single-photon emission computed tomography/computed tomography (CT) scans were acquired at 2 h post-injection of [(99m)Tc]MDP in two cohorts of animals at different sites: one cohort of mice at 6, 15, and 19 weeks of age, and a separate cohort at 16 weeks. The second cohort was also imaged with high-resolution CT at 8 weeks. RESULTS: mdx mice had higher [(99m)Tc]MDP uptake and significantly higher [(99m)Tc]MDP concentrations in muscle than controls. CONCLUSIONS: Higher uptake of [(99m)Tc]MDP in muscle of mdx mice agrees with histological reports of muscle calcification in mdx mice, and suggests the potential translational use of [(99m)Tc]MDP imaging for tracking DMD progression and therapeutic response. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11307-019-01394-7) contains supplementary material, which is available to authorized users.