MRI DIAGNOSIS OF SINUS CAVERNOUS INVASION BY PITUITARY-ADENOMAS

Purpose: To evaluate the preoperative MRI criteria of a sinus cavernou s invasion by a pituitary adenoma. Material and methods: Study of 102 cavernous sinuses among 51 patients who had had a surgical cure of pit uitary adenoma. Thirteen patients had a surgical invasion of the caver nous sinus. Results: A certain number of signs eliminated cavernous si nus invasion. The best means consisted in not crossing the intercaroti d line (Sensitivity-Se = 100%, Specificity-Sp = 85% and Negative Predi ctive Value-NPV = 100%). The others means implied : not going past twe lve o'clock on the internal carotid artery-ICA (NPV = 97.1%), symmetri cal size of the cavernous sinus (NPV = 92.5%), non-convexity of the la teral wall (NPV = 90.2%), visualization of at least two venous groups of the laterosellar space (NPV = 90.2%) and finally, non-displacement of the ICA (NPV = 89.2%). The best criteria for diagnosis were passing by the intra and supracavernous ICA lateral tangent (Se = 84.6%, Sp = 95%) and the percentage of ICA encasement by the adenoma exceeding 25 % (Se = 92.3%, Sp = 85%). Conclusion: Except the total encasement of t he intracavernous ICA, the cavernous sinus can be invaded when the lat eral tangent of the supra and the intracavernous ICA is crossed, and a lso when the percentage of ICA encasement exceeds 25%.