Assessment of calf muscle constitution in chronic Achilles tendon disease using Dixon-based MRI

Abstract

Objectives: To assess calf muscle constitution in chronic Achilles tendon disease (ATD) using two-point Dixon-based MRI (2pt-MRIDIXON). Materials and methods: This retrospective study analyzed 91 patients (36 females; 57.0 ± 14.4 years) with midportion or insertional chronic ATD who underwent clinical MRI of the Achilles tendon (AT), including 2pt-MRIDIXON for quantitative assessment of calf muscle fat content (MFC). Additionally, two radiologists qualitatively assessed MFC, AT quality, and co-pathologies. 2pt-MRIDIXON-derived fat fractions (FF) were related to patients’ demographics and qualitative imaging findings. Results: The overall mean FF derived from 2pt-MRIDIXON of the triceps surae muscle was 11.2 ± 9.3%. Comparing midportion and insertional ATD, there was no significant difference regarding fatty muscle infiltration assessed with 2pt-MRIDIXON (P ≥.47) or qualitative grading (P ≥.059). More severe AT thickening (11 vs.9 mm, P