Ultrasound Evaluation of Cysts and "Cyst-like" Lesions in and Around the Knee:In Comparison to Magnetic Resonance Imaging

The Benign knee cysts can be subdivided into four major categories as following:1- synovial cysts, 2- popliteal (Baker's) cyst, 3- ganglion cysts, 4- meniscal cysts. Whereas, The "cyst-like" lesions can be sub-classified into the following:1- normal knee bursae, 2- normal knee recesses, 3- miscellaneous cyst-like lesions as aneurysms, hematomas, seromas and abscess.

Many of these lesions have fairly characteristic locations and imaging features. Knowledge of these variants and lesions is essential for accurate diagnosis and to avoid mistaking them for aggressive soft tissue lesions, including sarcomas. Ultrasonography and magnetic resonance imaging are the most useful imaging modalities in evaluating these Benign cystic lesions. Ultrasonography can distinguish cysts from solid lesions and assess the degree of vascularity within the lesion. Magnetic resonance imaging can help to delineate the location of the lesion in relation to anatomic structures and also determine if the lesion is cystic or solid when contrast is administered.