Muscle infarction in patients with diabetes mellitus: MR imaging findings

PURPOSE: To describe the magnetic resonance (MR) imaging findings in diabet ic patients with muscle infarction and to describe commonly associated clin ical features. MATERIALS AND METHODS: The MR imaging studies of 21 patients with diabetic muscle infarction were reviewed retrospectively. Of the 21 patients, 12 wer e women, and nine were men; the mean age was 48 years (range, 30-77 years). RESULTS: Eight patients had bilateral lower-extremity involvement; six had involvement confined to the right lower extremity and seven to the left. Th e thigh was involved in 17 patients (81%). One or more of the musculi vastu s, the most frequently affected muscle group, were affected in 16 patients (76%). Four patients (19%) had isolated calf involvement. MR imaging studie s showed diffuse enlargement of involved muscle groups and partial loss of normal fatty intermuscular septa. MR imaging also allowed identification of areas of subfascial fluid in 16 patients (76%) and subcutaneous edema in 1 9 patients (90%). MR imaging showed involved muscle groups best with T2-wei ghted, inversion-recovery, and gadolinium-enhanced sequences, where the inf arcted muscles appeared diffusely hyperintense compared with adjacent muscl es. Comparison of T2-weighted and gadolinium-enhanced MR images of nine pat ients showed enlarged, enhancing muscles in all patients and small, focal, rim-enhancing fluid collections in six of nine patients (66%). CONCLUSION: Diabetic muscle infarction is suggested in diabetic patients wi th sudden onset of severe pain in the thigh or calf muscles who have MR ima ging findings of diffuse edema and swelling of multiple thigh and calf musc les (often in more than one compartment).