In this study, we evaluate the use of 3D-T1rho (T1ρ) relaxation mapping of the upper arm muscle glycosaminoglycan (GAG) content in healthy controls, and post stroke patients with pre and post hyaluronidase injections. Healthy controls (n=5) and post-stroke patients (n=5, pre and post treatment) were recruited. Dixon based water-fat imaging and T1ρ mapping were performed. Mono- and bi-exponential modeling was used to process the data. While water-fat distributions were not significantly different between the two groups, significant differences were noted in T1ρ values using mono- and bi-exponential analysis. T1ρ imaging shows significant changes that reflect the reduction of GAG’s following the treatment with hyaluronidase injection.