Machine learning‐based texture analysis for differentiationof radiologically indeterminate small adrenal tumors on adrenal protocol CT scans 
Ahmed W. Moawad et al.
Abdominal Radiology https://doi.org/10.1007/s00261-021-03136-2

“Adrenal protocol CT is the modality of choice for evaluating adrenal masses as it can characterize a nodule using both density measurements and contrast washout. An adrenal protocol CT consists of a dose reduced unenhanced CT followed by measurement of the attenuation of the nodule in question. If the attenuation of the adrenal mass is ≤ 10 HU (Hounsfield Units), then no further imaging is necessary. If attenuation is > 10 HU, then intravenous contrast is administered, and the patient imaged at 70 s and 15 min to calculate contrast washout. Attenuation based diagnosis of adrenal nodules relies on the presence of lipid within an adenoma which reduces mean attenuation within the entire nodule.”
Management of incidental adrenal masses: an update 
Daniel I. Glazer, William W. Mayo‐Smith 
Abdom Radiol (NY). 2020 Apr;45(4):892-900.

“When an incidental adrenal mass is discovered at imaging, three important items to determine are a history of malignancy, presence of prior abdominal imaging, and symptoms of a hyperfunctioning mass, as this will guide subsequent management. First, if the patient has a history of malignancy, then an incidental mass has a higher chance of being a metastasis although the risk is still only 26–36%. Second, if prior imaging is available, greater than 1 year of stability is indicative of benignity. Third, if the patient presents with signs or symptoms of adrenal hyperfunction (including hypertension or Cushing’s features) this is suggestive of a biochemically active neoplasm that would require further investigation.”
Management of incidental adrenal masses: an update 
Daniel I. Glazer, William W. Mayo‐Smith 
Abdom Radiol (NY). 2020 Apr;45(4):892-900.