MR IMAGING OF PINEAL REGION NEOPLASMS

Twenty-eight patients with tumor of the pineal region underwent magnetic resonance (MR) examination. Gadolinium DTPA was given to 13 patients. Histologic confirmation was obtained in all patients, including 10 germinomas, 4 pineocytomas, 4 pineoblastomas, 5 astrocytomas, 2 teratomas, 1 choriocarcinoma, 1 mixed germ cell tumor, and 1 metastasis from breast carcinoma. Pineal region neoplasms have remarkable heterogeneity in both histopathologic and MR appearances. Gadolinium DTPA enhanced MR increases the specificity of diagnosing pineal region neoplasms. In addition Gd-DTPA provides better delineation of the tumor margin and demonstrates cystic components of the neoplasm. Our approach to pineal region neoplasms is to make a decision about whether stereotaxic biopsy or surgery should be performed on a certain patient. When a pineal region neoplasm is diagnosed as benign, such as a benign teratoma, on the basis of imaging, surgery is performed to resect the entire lesion. When a definitive diagnosis is not possible, sterotaxic biopsy is performed to obtain histological diagnosis for treatment planning. Gadolinium DTPA enhanced MR plays an extremely important role in target selection in stereotaxic biopsy of pineal region neoplasms and is also useful in the early detection of intracranial seeding. Spinal seeding is demonstrated on MR as well, thus alleviating the need for a contrast myelogram. Finally, Gd-DTPA enhanced MR can be used to monitor the effects of the various treatment modalities employed for pineal region neoplasms.