Page 266 - Atlas of Small Animal CT and MRI

256 Atlas of Small Animal CT and MRI

Figure 2.9.13 Pituitary Adenoma (Canine) MR

(a) T1, SP (b) T1, TP (c) T2, TP

(d) T1+C, SP (e) T1+C, TP (f) GP, TP
10y MC Golden Retriever with a 6‐day history of progressive obtundation. Images b, c, and e are representative transverse images at
the level of the pituitary fossa. Images a and d are comparable images oriented in the sagittal plane. The pituitary gland is markedly
enlarged (height = 20 mm, width = 19 mm) and has a cystic component that is both T1 and T2 hyperintense (b,c: large arrow). The
peripheral parenchymal component of the mass is T1 isointense compared to deep gray matter (a,b: small arrow) and is of mixed, but
low, T2 intensity (c: small arrow). Mild peripheral edema is also evident (c: arrowhead). A deflated cystic cavity (f: small arrows) and
hemorrhage within the remaining pituitary parenchyma (f: large arrow) are seen on the transected gross specimen. Imaging features
are consistent with a large cystic pituitary mass with hemorrhage in the parenchymal component. The cyst fluid is hyperintense on both
T1 and T2, likely due to high lipid content or T1 shortening solutes. The mass was determined to be a nonfunctional macroadenoma
arising from the pars intermedia.

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