抄録
CT examination of sellar lesions was studied from the methodological aspect in 141 CT scans performed in 59 patients with suspected pituitary lesions.
The basic scanning line was determined in parallel to the line from the tuberculum to the dorsum sella using a “scout view” device. The angles formed by the orbito-meatal line and the tuberculumdorsum sella line as measured in 50 adults were 1.8±6.4° in males and −6.4±4.8° in females. Therefore, if the CT scanner is not equipped with a scout view, these mean angles may be used as the basic scanning line. Contiguous sections were obtained with a CTT 8800 scanner at 1.5 mm intervals through the sella, under the radiographic condition of 120 kV, 500 mA and 2 pulses, which proved suitable for the detection of minor lesions below 10 mm in size and for examination of the pituitary stalk. Window width of 250 or 300 Hounsfield units and window levels ranging from 50 to 60 were well suited to the detection of small lesions. Not only the axial sections but also coronal and sagittal computer reconstructions were helpful in the detection of lesions.
Twenty-eight cases of pituitary adenoma, 3 of empty sella alone, and 1 of sphenoidal mucocele were confirmed by CT scan. The pituitary adenomas consisted of 8 Type I, 13 Type II, 2 Type III, and 5 Type IV after the classification of Hardy. By enhancement with a contrast medium, the normal pituitary appeared higher in density than the brain, and the intrapituitary small tumor appeared slightly lower in density than the normal pituitary. CT scanning under the above-mentioned display condition could discriminate the tumor from the normal pituitary in at least 24 cases which were surgically confirmed. Shifting or bending of the pituitary stalk found in the reconstructed coronal or sagittal sections were useful for the diagnosis of intrasellar pituitary tumors. The empty sella was effectively diagnosed by CT cisternography using metrizamide as a contrast medium.
