Extrapineal abnormalities of the tectal region: MR imaging findings.

This essay illustrates the imaging spectrum of extrapineal lesions that involve the tectal region, with emphasis on intrinsic tectal abnormalities. The superb sensitivity of MR and its multiplanar imaging capability permit unparalleled diagnostic accuracy in this region. The sagittal and axial planes are ideal for evaluating the tectum. CT remains important in the detection of acute hemorrhage and calcification. Grouping of abnormalities on the basis of anatomic boundaries (tectum, aqueduct, and quadrigeminal plate cistern) is useful in establishing the correct diagnosis.