Abstract: Objective 　To investigate the anatomic changes of sphenoid sinus and the significance in patients with pituitary adenoma in transsphenoidal surgery by 3D CT.　Methods　The imaging data of 51 patients with pituitary adenoma in our hospital from March 2014 to March 2015 were collected. Before the operation, the CT images of the paranasal sinuses were input into the computer, and the separation of the sphenoid sinuses was reconstructed by using the software of mimics15.0. The number, shape and deviation of the sphenoid sinuses were observed and recorded, and they were compared with those of during the operation. The gasification types of the sphenoid sinuses, the internal carotid protrusion and fissuring and the incidence of Onodi cell chamber were observed.　Results　Among the 51 cases, the sphenoid sinus presented anterior sellar type in 3 cases, semi sellar type in 12 cases, sellar type in 18 cases and sella occipital type in 18 cases. The sphenoid sinus had no septum in 1 case, 1 mediastinum in 36 cases, 2 mediastinum in 11 cases, 3 mediastinum in 2 cases. The tumor was filled with the sinus cavity and the number of septum could not be determined in 1 case. There were 2 cases of transverse septum and 1 case of oblique septum. The anterior edge of the septum was the middle in 19 cases left in 14 cases on the, right in 16 cases. The anterior edge of the septum was damaged by tumor and could be judged in 1 case. In 5 cases, the posterior margin of 7 sides of sphenoid sinus was attached to the carina of internal carotid artery. There were 12 cases of bilateral internal carotid artery carina, 2 cases of unilateral internal carotid artery carina and 5 cases of internal carotid protrusion fissure. Onodi cell chamber was found in 9 sides of 5 cases. In all patients, the bony separation in the sphenoid sinus was consistent with the three-dimensional reconstruction image before operation. The localization of the sellar base was realized quickly and accurately under the guidance of the sphenoid sinus separation.　Conclusions　CT three-dimensional reconstruction technique can display the bony separation in the sphenoid sinus and the protrusion of the lateral wall of the sphenoid sinus well, which is helpful for rapid and accurate localization in transsphenoidal surgery.

Key words:  , Sphenoid sinus, 　Septum, 　Pituitary adenoma, 　Transsphenoidal surgery, 　CT, 　Image evaluation