[Neuroimaging of Pituitary Neuroendocrine Tumors].

Magnetic resonance imaging(MRI)is the preferred imaging technique for sellar and parasellar regions. In this study, we report our clinical experience with MRI for pituitary neuroendocrine tumors(PitNETs)with reference to histopathological findings through a review of the literature. Our previous study indicated that the three dimensional-spoiled gradient echo(3D-SPGR)sequence is suitable for evaluating sellar lesions on a postcontrast T1 weighted image(T1WI). This image demonstrates a defined relationship between the tumor and its surroundings, such as the normal pituitary gland, cavernous sinus, and optic pathway. This 3D-SPGR sequence is also suitable for detecting microtumors in corticotroph PitNETs. In somatotroph PitNETs, the signal intensity on T2WI is important to differentiate densely granulated tumors from sparsely granulated somatotroph tumors. In lactotroph PitNETs, distinct hypointense areas in the early phase on T2WI, possibly due to diffuse hemorrhage, indicate pronounced regression of invasive macroprolactinomas during cabergoline therapy.