Diagnosis of Cavernous Sinus Invasion by Pituitary Adenomas: MRI of Internal Carotid Artery

Objective To study the effect of pituitary adenomas on internal carotid artery (ICA) in evaluating the cavernous sinus invasion. Methods MRI of 103 patients with pituitary adenomas verified by pathology was studied. The distance between the ICA and midline, encasement of intercavernous ICA and the volume of the tumor were measured. Results The mean ICA distance was (24.44±4.22)mm. It was related to the width of the tumor which was more significant than the volume. Cavernous sinus invasion was related to the extent of encasement of ICA. The other items were not related to cavernous sinus invasion. Conclusion It was not the volume but the width of the tumor determined the intercarotid distance. Cavernous sinus was not invaded when the encasement of ICA was less than 1/3, and cavernous sinus invasion was certain when the encasement was more than 2/3.The evaluation of the effect of pituitary adenomas on ICA might play an important role in guiding operations.[