MR diagnosis and differential diagnosis of cystic lesions in knee joint area

Objective:To explore the MR diagnosis and differential diagnosis of common cystic lesions in knee joint.Methods:1500 cases received the magnetic resonance(MR) examination of knee joints in our hospital from September 2005 to September 2010.102 cases of cystic lesion in knee joint area and periarticular area were collected for analysis.Results:Synovial cyst(54 cases),meniscus cyst(22 cases) and thecal cyst(23 cases) were the most common cystic diseases in knee joint area,there were 3 cases of other diseases.Among them,91 cases revealed long T1 and long T2 in signal intensity,8 cases revealed slight short T1 in signal intensity,3 cases were combined with other signal intensity.There were many synovial bursas around knee joint area,synovial cyst lied in special area,popliteal cyst lied in popliteal fossa,connecting with joint cavity through a narrow channel and showing irregular shape;most of meniscus cysts were located near themselves,always gathered in a row,few in the meniscus;thecal cyst kept up with tendon sheath in direction,showing oval shape,sometimes multiple or housing distribution.Conclusion:Most cyst lesions reveal long T1 and long T2 in signal intensity.Grasping the knowledge of knee joint's anatomy and pathology knowledge of different cystic lesions is most important for diagnosis and differential diagnosis.