MR imaging of mediastinal masses.

Although ongoing developments in MR imaging have resulted in improved image quality and decreased acquisition time, MR imaging is largely used as an adjunct to CT scanning in the evaluation of mediastinal abnormalities. In this role, MR imaging often provides additional information about the nature, location, and extent of disease. MR imaging is useful in confirming the cystic nature of mediastinal lesions that appear solid on CT and, by revealing small amounts of intralesional fat, can suggest the diagnosis of hemangioma, teratoma, or extramedullary hematopoesis. MR imaging is the preferred modality for imaging neurogenic tumors, because its multiplanar capability and high contrast resolution can best demonstrate the number and nature of the lesions (differentiating cysts from neoplasms), intraspinal extension, and craniocaudad extent. MR imaging is also especially useful for evaluating the mediastinum of patients for whom the administration of iodinated contrast material is contraindicated.