[Computed tomography of suprasellar cystic lesions].

Difficulties are often encountered in the differential diagnosis of suprasellar cystic lesions in computed tomography (CT). During the past 5 years and 7 months we experienced 22 such cases. In this report we tried to review the characteristic CT findings for the differential diagnosis of these lesions. Population of this study is consisted by 7 pituitary adenomas (4 non-functioning adenomas, 2 prolactinomas and 1 GH-secreting adenoma), 8 craniopharyngiomas, 4 arachnoid cysts and 3 Rathke's cleft cysts. In cases of pituitary adenomas and craniopharyngiomas, we included only those cases which were found to be completely cystic. Each case was scanned before and after contrast material injection and in majority of cases coronal scans were also obtained after contrast injection. The analysis was based on the CT appearance of the shape, the content and the wall of each cyst. The wall of the cyst was evaluated according to its thickness, density, presence of calcification and contrast enhancement. In 14 out of 22 cases the X-ray attenuation values of their content were calculated after setting the ROI in the cyst on the CT display console. Craniopharyngioma often showed calcification in its wall, which was not seen in the wall of pituitary adenoma. The wall of pituitary adenoma revealed contrast enhancement in all cases, but half of craniopharyngioma showed no contrast enhancement in its wall. These two points are useful for the differential diagnosis of these lesions which we encounter most frequently.(ABSTRACT TRUNCATED AT 250 WORDS)