Direct coronal CT: an aid to the diagnosis of sellar lesions.

The qualities of the CT scanners used have a decisive influence on the results presented in various papers dealing with sellar CT examinations. Our conclusions are presented with this in mind. In the great majority of cases, direct coronal CT through the sellar area is available and gives essential information about this region. The size and origin of a tumour can be determined and differential diagnosis between a tumour and an empty sella is possible. Coronal scanning must be considered a necessary part of sellar region CT. The use of lateral digital localizer seems essential in order to avoid the main shortcoming of this modality, namely artifacts caused by metallic dental fillings. However, in a certain significant number of cases difficulties still exist. Artifacts cannot always be avoided and diagnostic slices cannot then be obtained. The differential diagnosis between an empty sella and a cystic lesion, between different tumour types or between an aneurysm and tumour may also sometimes be impossible. Computer histographic analysis, sequential or dynamic CT studies as well as carotid angiography may increase the chances of differential diagnosis between neoplasms, and carotid angiography is essential in the detection of vascular lesions. The problem of truly reliable microadenoma detection has not so far been solved. The significant frequency of examinations spoiled by artifacts emphasizes the need for high quality reconstructions and also points to the fact that metrizamide cisternography with hypocycloid tomography still has a definitive role in radiological examination of the sellar area.