CT of the normal pituitary stalk.

A prospective study assessed the size and frequency of visualization of the normal pituitary stalk on high-resolution computed tomography (CT). The normal pituitary stalk can be seen on the vast majority of high-resolution scans obtained with thin sections and intravenous contrast material. The upper size limit of the normal pituitary stalk is 4 mm at the level of the dorsum sellae and 4.5 mm above the dorsum. Stalks larger than this should be viewed with suspicion. Comparison of the size of the pituitary stalk with that of the nearby basilar artery is possible on most CT scans, providing a convenient and reliable visual check of the size of the stalk.