Hypophysis

HRCTand Multiplanar MRI have become popular in imaging of hypophysis.

CT: Both coronal and axial images are required to study the extent of the lesion. Thin sections (1.5mm) in the coronal plane is ideal.

Multiplanar MR imaging: permits more accurate evaluation of the pituitary micro-adenomas as well as macroadenomas.

Note : Type of sphenoid pneumatization. Conchal type sphenoid is a relative contraindication for transsphenoidal hypophysectomy. Internal carotid aneurysm in the visinity of hypophysis is absolute contraindication. Note thinning of the bony margins of the sella, erosion of the anterior clinoid process and dorsum sellae, and extensions of tumor into the sphenoid sinus.

Fig. :Axial Section: Pituitary adenoma bulging into the sphenoid sinus. Pituitary adenomas appear isodence on plain CT.

Fig. :Axial Section: Contrast CT showing solid portions of pituitary macro-adenomas exhibit moderate to significant homogenous contrast enhancement.

Fig. : Coronal Section: Contrast CT showing areas of necrosis seen in large adenomas appear as irregularly marginated foci of hypodensity which do not enhance with contrast.

Fig. : Coronal Section: Contrast CT showing Macro adenoma: Notice sella nad anterior clinoid process erosion.