CT and MRI diagnosis of cystic lesion in the mediastinum

Objective:To study the CT and MRI diagnosis and differential diagnosis of mediastinal cystic lesions.Methods:30 cases of mediatinal cystic lesions were examined by CT and MRI scans, all cases were confimed by surgical and pathological findings.This group included following diseases:thymic cyst(n=7),cystic teratoma(n=8),tracheal and bronchial cyst (n=9),esophageal cyst (n=4) and lymphangioma (n=2).Results:Different kind of mediastinum cysts had different location.Of 7 thymic cysts,6 were at anterior superior mediastinum in thymic region,1 was at anterior mediastinum in middle and lower region;8 cystic teratomas were at anterior mediastinum in middle region near the origin of the great vessels;9 tracheal and bronchial cysts were at middle mediastinum,near the tracheal and bronchial region;as for 4 esophageal cysts,3 were at posterior mediastinum;1 was at middle mediastinum;of 2 lymphangiomas one was cervico mediastinal type,another was cervico axillary mediastinal type.Conclusion:There is no pathognomoic imaging features for mediastinal cystic lesions.However,it is very important to improve the diagnosis of these lesions when their CT and MRI features are carefully analyzed in combination with their location.