Direct coronal images are obtained with the patient positioned in a headholder and the neck extended comfortably to a maximal point. Gantry tilt is utilised to obtain an optimal coronal positioning, perpendicular to the sellar floor, while avoiding dental amalgam artefacts. A lateral localiser image is used to select contiguous corona] images, with a slice thickness of about 1.5mm. If the patient cannot be positioned for direct coronal imaging, reformatted coronal images can be obtained from axial images. Intravenous contrast medium (containing 30-40g of iodine) is administered immediately prior to the scan. Patients with a contrast allergy need to be premedicated with corticosteroids given twenty-four hours, twelve hours, and two hours prior to the study.
