CT adrenals (protocol)

Last revised by Andrew Murphy on 23 Mar 2023

CT of the adrenal glands is a study utilized in patients with incidentally discovered adrenal lesions on other studies, in order to characterize the lesions, and to seek adrenal abnormalities in patients with hormonal biochemical abnormalities.

Characterize incidentally discovered adrenal nodules and seek adrenal abnormalities when clinically suspected.

To characterize adrenal nodules on the basis of the density on non-contrast and post-contrast imaging, and washout characteristics. Nodules with lipid density measurements on the non-contrast series can be diagnosed as lipid-rich adenomas, and in nodules that are not lipid-rich, washout calculations can be used to differentiate between lipid-poor adenomas and indeterminate lesions, with differentials for the latter including adrenocortical carcinoma and pheochromocytoma.

  • patient position
    • supine with their arms above their head
  • scout 
    • diaphragm to iliac crests
  • scan extent 
    • diaphragm to iliac crests
  • scan direction
    • craniocaudal
  • scan delay
    • non-contrast series: no delay
    • portal venous phase series: 60-70 second delay
    • delayed phase series: 15-minute delay
  • respiration phase
    • inspiration, breath-hold
  • the choice of which incidental lesion to investigate may be determined by published algorithms such as the ACR White Paper
  • density measurements <10 HU using region-of-interest calculations on a non-contrast series indicates a lipid-rich adenoma or a myelolipoma
  • if the density is >10 HU on the non-contrast series, the density measurements on the portal venous and delayed phase studies may be used to calculate the relative and absolute washout; several online washout calculators are listed in the adrenal washout article

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