Objective To analyze the relation between cavernous sinus and pituitary macroadenoma in various magnetic sequences imaging(MRI)criteria and to identify the prediction accuracy of preoperative MRI for cavernous sinus(CS)invasion by pituitary macroadenoma. Methods We retrospectively reviewed the preoperative MRI of 212 patients with pituitary macroadenoma who underwent endoscopic transsphenoidal surgery. The following MR signs were assessed and compared with intraoperative findings:(1)Integrity of the medial wall of cavernous sinus with a hypointense signal on coronal T₂-weighted image;(2)Presence of entire rim-enhancement around the intracavernous internal carotid artery(ICA)on T₁-weighted image;(3)The relationship between the edge of the tumor and the lateral intercarotid lines;(4)Relationship between tumor and inferior space of internal carotid in cavernous sinus. Moreover, the angle of tumor encasement around the intracavernous ICA was analyzed by Receiving Operative Characteristic curve. Results The intraoperative finding confirmed CS invasion in 36 of 212 patients with pituitary macroadenoma. When four MRI signs were used in combination, the sensitivity and specificity, and positive predictive value were 91.7%, 97.2%, and 92.8%, respectively. A threshold value of 135° was associated with a high probability of CS invasion, with a sensitivity of 88.9% and a specificity of 84.1%. Conclusions The combination of various preoperative MRI signs may be helpful in evaluating the presence of CS invasion. Comprehensive therapeutic plan may be optimized if preoperative determination of the presence of CS invasion is performed.