What is the role of imaging studies in the workup of hyperpituitarism?

Updated: Oct 24, 2016
  • Author: Alicia Diaz-Thomas, MD, MPH; Chief Editor: Robert P Hoffman, MD  more...
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If laboratory findings suggest pituitary hormone excess, the presence of a pituitary adenoma should be confirmed using MRI. The T1-weighted spin-echo MRI of the pituitary before and after administration of gadolinium (Gd) is the imaging modality of choice for detecting pituitary adenomas. [6]

Coronal and sagittal images should be obtained at 3-mm intervals before and after contrast, focusing on the pituitary region.

Adenomas are slow to take up Gd compared with the surrounding normal pituitary tissue and therefore appear as hypoenhancing lesions.

In some cases, a pituitary mass is not identified. Be aware that a pituitary microadenoma can be occult and that an ectopic tumor rarely occurs.

Conventional T1-weighted MRI still is only able to detect approximately one third to one half of microadenomas.

Magnetic resonance imaging (MRI) may have a role in the diagnosis of Cushing disease. In one series, MRI with spoiled gradient recalled echo (SPGR) sequences detected adenomas in 15% of patients that were not detected by standard spin echo. [7] More sensitive imaging of the adenoma in Cushing disease confers several advantages, including confirmation of the diagnosis and location and avoidance of the risks of inferior petrosal sinus sampling; positive MRI findings help confirm the diagnosis of Cushing disease. Nevertheless, there is limited accuracy in the MRI's prediction of dural invasion.

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