CT analysis of intrasellar pituitary adenomas with emphasis on patterns of contrast enhancement.

Analysis of the computed tomograms of 85 purely intrasellar pituitary adenomas documents a highly variable pattern of response to contrast enhancement. Twenty-eight of 85 adenomas exhibited homogeneously increased density. Twenty exhibited heterogeneously increased, patchy or ringlike density; 16, hypodensity; and 8, isodensity with normal pituitary tissue. In 13 patients the predominant CT finding was an empty sella with variable enhancement of the adenoma and residual pituitary tissue. Pathological specimens demonstrated that the hypodense zones observed within pituitary microadenomas may represent pituitary necrosis, cyst, hemorrhage, intratumoral abscess, relatively less intense enhancement than the normal surrounding pituitary tissue.