In trans-sphenoidal pituitary adenoma surgery the sella turcica is opened between the internal carotid arteries. Three-dimensional image processing methods were applied in this study to avoid the risk of damaging the arteries during the opening of the anterior wall of the sella. By using graphical software it was possible to combine the anatomies of the carotid arteries and the sellar wall into one non-perspective three-dimensional image. With a perspective image (virtual endoscopy), the sphenoid sinus landmarks were presented as if looking through a nasoendoscope. This also facilitated preoperative planning but the non-perspective images, with the carotid arteries marked, were found to be the most useful and suitable for clinical routine. The pituitary tumor itself and its relations with the adjacent structures were best evaluated from magnetic resonance imaging scans but, for the opening of the sellar wall and in the three-dimensional orientation with endoscopy, three-dimensional computerized tomography imaging with the carotid arteries marked was found to be helpful.