MR imaging of the sellar and juxtasellar regions.

Multiplanar capability and superior tissue contrast differentiation render magnetic resonance (MR) imaging the preferred method for examining patients with pituitary axis dysfunction or visual field deficits. In a review of 131 sellar or juxtasellar abnormalities, 76% were common lesions with distinctive features that helped establish their diagnosis: macroadenoma (n = 51), microadenoma (n = 20), meningioma (n = 14), craniopharyngioma (n = 10), and aneurysm (n = 5). On T1-weighted images, microadenomas were usually hypointense relative to normal pituitary gland, and macroadenomas and meningiomas were isointense relative to gray matter. Both microadenomas and meningiomas were more conspicuous immediately after contrast material administration. Craniopharyngiomas were the most heterogeneous of all the sellar lesions due to their cystic and solid components. MR images of aneurysms showed flow void and heterogeneous increased signal intensity in areas of slower turbulent flow. Other characteristics such as extrasellar versus intrasellar location, nature of contrast material enhancement, the presence of cystic components, and clinical findings permitted differentiation among less common lesions, including granulomatous disease, metastases, chiasmatic glioma, arachnoid cyst, hypothalamic glioma, schwannoma, germinoma, epidermoid, Rathke cyst, chordoma, chondrosarcoma, colloid cyst, and hamartoma.