Supratentorial ependymomas and subependymomas: CT and MR appearance

Our goal was to characterize the CT and MR features of supratentorial ependymomas and subependymomas. The CT or MRI examinations of 11 supratentorial ependymomas (average patient age: 16 years) and 3 supratentorial subependymomas (average age: 60 years) were analyzed for tumor size, location, and appearance. Ependymomas were periventricular (nine), intraventricular (one), or both (one) and averaged 4 cm in diameter. Four of nine ependymomas examined by CT were calcified. Eight ependymomas had a cystic component. All seven ependymomas evaluated with MRI demonstrated prolonged T1 and T2 relaxation, with two having foci thought to represent intratumoral hemorrhage. The MR contrast enhancement patterns included an enhancing nodule within the wall of a cyst (four), heterogeneous enhancement of cystic/solid lesions (two), and homogeneous enhancement of a solid lesion (one). All subependymomas were solid intraventricular masses, averaging 2.6 cm in diameter. One had small amounts of calcification, and none were cystic. All three were isointense or hypointense to white matter on T1-weighted MR images and heterogeneous or hyperintense on T2-weighted images, with variable enhancement characteristics. Early (< 1 year) postsurgical recurrence was seen in two ependymomas and one subependymoma. Supratentorial ependymomas are typically large, cystic, calcified, extraventricular masses found in children and young adults. Supratentorial subependymomas are generally solid, intraventricular masses that are usually smaller than ependymomas and occur in an order patient population.