MRI with and without IV contrast plays an important role in characterizing lesions of the sella, suprasellar cistern, and any cavernous sinus invasion [64,65]. MRI with IV contrast may only be performed for use in operative guidance, and should not be considered a first-line imaging test. MRI can confirm absence or ectopia of the posterior pituitary gland. Pituitary underdevelopment may be suggested on the basis of imaging; however, objective criteria for pituitary hypoplasia do not exist [40,42,48]. An empty sella is well characterized on MRI, even without IV contrast [19]. Venous Sampling Petrosal Sinus Venous sampling of the cavernous sinuses is not useful in the setting of pituitary hypofunction. Venous sampling is reserved for cases in which a definite excess of pituitary hormone is present, medical management has failed, cross-sectional imaging is negative or equivocal, and surgery is planned [66-68]. Radiography Sella Radiography is insensitive and nonspecific for evaluating sellar pathology. Pituitary adenomas are frequently associated with a normal sella size. The sella turcica can be enlarged by the presence of a pituitary adenoma or other pathophysiological conditions such as pulsation of cerebral spinal fluid through a developmental or acquired dehiscence of the diaphragm sella in the empty sella syndrome [69]. Neuroendocrine Imaging CT Sella CT has the ability to identify large pituitary tumors, and contrast-enhanced CT may define some microadenomas [28,70-73], although MRI is more sensitive. Dual-phase imaging with and without IV contrast is not indicated as an initial imaging study. Larger tumors may cause sellar remodeling, including sellar enlargement, bony erosion, supra sellar extension, invasion into the clivus, or sphenoid sinus. CTA Head CTA may be part of operative planning or image guidance; however, CTA is not routinely used in the initial evaluation of known or suspected hyperfunctioning pituitary adenoma [20].
Neuroendocrine Imaging. MRI with and without IV contrast plays an important role in characterizing lesions of the sella, suprasellar cistern, and any cavernous sinus invasion [64,65]. MRI with IV contrast may only be performed for use in operative guidance, and should not be considered a first-line imaging test. MRI can confirm absence or ectopia of the posterior pituitary gland. Pituitary underdevelopment may be suggested on the basis of imaging; however, objective criteria for pituitary hypoplasia do not exist [40,42,48]. An empty sella is well characterized on MRI, even without IV contrast [19]. Venous Sampling Petrosal Sinus Venous sampling of the cavernous sinuses is not useful in the setting of pituitary hypofunction. Venous sampling is reserved for cases in which a definite excess of pituitary hormone is present, medical management has failed, cross-sectional imaging is negative or equivocal, and surgery is planned [66-68]. Radiography Sella Radiography is insensitive and nonspecific for evaluating sellar pathology. Pituitary adenomas are frequently associated with a normal sella size. The sella turcica can be enlarged by the presence of a pituitary adenoma or other pathophysiological conditions such as pulsation of cerebral spinal fluid through a developmental or acquired dehiscence of the diaphragm sella in the empty sella syndrome [69]. Neuroendocrine Imaging CT Sella CT has the ability to identify large pituitary tumors, and contrast-enhanced CT may define some microadenomas [28,70-73], although MRI is more sensitive. Dual-phase imaging with and without IV contrast is not indicated as an initial imaging study. Larger tumors may cause sellar remodeling, including sellar enlargement, bony erosion, supra sellar extension, invasion into the clivus, or sphenoid sinus. CTA Head CTA may be part of operative planning or image guidance; however, CTA is not routinely used in the initial evaluation of known or suspected hyperfunctioning pituitary adenoma [20].