Magnetic resonance imaging of ruptured Baker's cyst.

The clinical presentation of a ruptured Baker's cyst and of thrombophlebitis can be identical. Venography, arthrography, and more recently ultrasonography have been used to differentiate these two entities. We report a patient with a ruptured Baker's cyst who was also evaluated using magnetic resonance imaging (MRI). The soft-tissue abnormalities were better demonstrated by MRI than by the other imaging methods.