Fig. 24.1
Tumor shrinkage. Coronal T2-weighted (a) and coronal post-contrast T1-weighted (b) MR images show a pituitary prolactinoma (arrows) that compresses the optic apparatus. Coronal T2-weighted (c) and coronal post-contrast T1-weighted (d) MR images obtained several months after treatment with bromocriptine show interval marked decrease in size of the mass (arrows) and no residual compression of the optic apparatus
Fig. 24.2
Chiasmal herniation. MR images from a patient with a history of pituitary adenoma, treated with bromocriptine long ago. Of note, the patient never had pituitary surgery. Sagittal T1-weighted (a), coronal T2-weighted (b), and coronal post-contrast T1-weighted (c) MR images show an expanded empty sella with a distorted and inferiorly displaced optic chiasm, particularly on the left side (arrows)
Fig. 24.3
Cystic change. Coronal post-contrast T1-weighted (a) and coronal T2-weighted (b) MR images before cabergoline treatment show an enhancing T2 hypointense right pituitary microadenoma (arrows). Coronal post-contrast T1-weighted (c) and coronal T2-weighted (d) MR images obtained several months after cabergoline therapy show interval lack of enhancement and T2 hyperintensity with in the lesion (arrows)
Fig. 24.4
Intratumoral hemorrhage. Axial FLAIR (a), sagittal T1-weighted (b), coronal T1-weighted (c), and coronal T2-weighted (d) MR images obtained shortly after starting cabergoline treatment shows hemorrhage within a left pituitary microadenoma with a fluid-fluid level (arrows). Follow-up coronal T1-weighted (e) and coronal T2-weighted (f) MR images obtained several months later show resolution of the hemorrhage with overall slight interval decrease in size of the lesion
24.4 Differential Diagnosis
Pituitary tumors, particularly macroadenomas, may undergo spontaneous hemorrhage without dopamine agonist therapy (Fig. 24.5). Alternatively, apoplexy may occur in pituitary glands that do not contain tumors, particularly in the postpartum period (Sheehan syndrome). Other conditions may resemble hemorrhage, such as cystic tumors, including Rathke cleft cysts, which may also contain layering debris or a T2 hypointense nodule (Fig. 24.6).
