Magnetic resonance imaging of painful swollen legs in the emergency department: a pictorial essay

Patients presenting with a painful swollen leg are not infrequently encountered at the emergency department and can pose a diagnostic dilemma for attending physicians. The potential causes of leg pain and swelling include trauma, infection, inflammation, and neurogenic, vascular, and iatrogenic conditions; with magnetic resonance imaging (MRI) being an important tool in evaluation. We describe the MRI features of various conditions causing painful swollen legs. We also discuss the differential diagnosis and the useful clinical and laboratory findings that radiologists should be aware of, in order to arrive at an accurate diagnosis.