Magnetic resonance arthrographic demonstration of knee joint communication in isolated popliteal artery cystic adventitial disease.

Cystic adventitial disease is a rare, nonatherosclerotic condition most commonly affecting the popliteal artery in the popliteal fossa. We describe the case of a 44-year-old man with episodic calf claudication in whom duplex ultrasound and computed tomography angiography showed cystic lesions surrounding the popliteal artery with mild luminal narrowing, consistent with cystic adventitial disease. Conventional magnetic resonance (MR) imaging identified a popliteal artery adventitial cyst with suspected knee joint connection. Fluoroscopically guided intra-articular gadolinium injection in the knee followed by 3-T MR arthrography confirmed cyst communication with the knee joint. This case supports the articular theory and highlights MR arthrography as a problem-solving tool in selected cases.