Presentation
Known leukocytoclastic vasculitis. Now severe right calf pain, ? myositis
Patient Data
MRI to detect sites of myositis prior to targetted biopsy
Diffuse edema in the gastrocnemius and soleal muscles of the right leg associated with expansion of the calf veins filled with T1 and T2 hyperintense material indicative of clot. All other calf and thigh muscles are normal. Note left calf veins do not contain T1 hyperintensity i.e. methemoglobin.
Case Discussion
MRI (especially STIR imaging) is exquisitely sensitive to muscle edema and can be used to localize sites of muscle swelling that be targetted for biopsy (to diagnose myositis). It is, however, no specific as in this case i.e. the patient has muscle swelling not due to inflammation rather due to venous obstruction by thrombosis.