Methods: This prospective study included 32 patients (15 males, 17 females; mean age 51 years; range 24 to 86 years) with solid or cystic mediastinal mass lesion and suspected of invasion. Firstly, patients were performed posteroanterior chest radiography and chest computed tomography scan. Then, lesions’ static morphological characteristics were investigated with conventional MRI (T₁, T₂, short T₁ inversion recovery). Dynamic characteristics of lesions were shown with cine MRI in three planes. Lesions were evaluated in terms of shape, size, motion, and relationships with adjacent tissues.

Results: Of 32 patients, 17 were operated with 13 patients having benign cysts (four mediastinal goiters, two teratomas, two pericardial cysts, one bronchogenic cyst, one hydatid cyst, one neurenteric cyst, one schwannoma, and one aorta aneurysm), and four patients having malignant cysts (two esophagus cancer, one lung cancer, and one synovial sarcoma). Preoperative cine MRI showed no invasion in 16 of these patients, and presence of invasion in one patient. Our findings were consistent with the operation results. It was thought that seven of the 15 patients who were diagnosed histopathologically had invasion. Of these 15 patients, 13 had malignant cysts (seven lung cancer, three lymphomas, one esophagus cancer, one mesothelioma, and one thymoma) and were accepted clinicoradiologically inoperable. Treatment was started in two patients who were detected to have osseous inflammatory pathology and tuberculosis lymphadenitis. Cine MRI was statistically significantly superior than conventional MRI in showing invasion to mediastinal structures (p<0.001).

Conclusion: Cine MRI may provide significant assistance in diagnosis of mediastinal lesions and evaluation of their relationships with adjacent tissues.