Ruptured and dissecting popliteal cysts on magnetic resonance imaging and computed tomography

A sagittal MRI of the knee (A) using a fat saturated proton density sequence shows a popliteal cyst (asterisk) with a thin layer of fluid dissecting in the muscle planes. Image B is a CT and shows a decompressed popliteal cyst (asterisk) with multi-centric regions of thick-walled dissecting fluid collections (arrows).