Clinical utility of noncontrast computed tomography attenuation value (hounsfield units) to differentiate adrenal adenomas/hyperplasias from nonadenomas: Cleveland Clinic experience

J Clin Endocrinol Metab. 2005 Feb;90(2):871-7. doi: 10.1210/jc.2004-1627. Epub 2004 Nov 30.


Radiological characterization of an adrenal tumor as adenoma may decrease the need for follow-up imaging studies, biopsies, and unnecessary adrenalectomies. We retrospectively reviewed 299 adrenalectomies in 290 patients at Cleveland Clinic Foundation over a recent 5-yr period to assess the value of noncontrast Hounsfield units (HU) in characterizing whether an adrenal mass is adenoma or nonadenoma. The mean (+/- SD) HU value for the adrenocortical adenoma/hyperplasia group was 16.2 +/- 13.6 and significantly lower (P < 0.0001) than primary adrenocortical cancers (36.9 +/- 4.1), metastases (39.2 +/- 15.2), and pheochromocytomas (38.6 +/- 8.2). The sensitivity and specificity for 10- and 20-HU cutoff values to differentiate adenomas/hyperplasias from nonadenomas were 40.5 and 100% and 58.2 and 96.9%, respectively. The size of the adrenal tumor had less value with only 40.7 and 81.3% sensitivity and 94.7 and 61.4% specificity for 2- and 4-cm cutoff values. A combination of less than or equal to 4-cm adrenal mass size and noncontrast computed tomography HU less than or equal to 20 had 42.1% sensitivity and 100% specificity. Our study, the largest with surgical histopathology as the gold standard for diagnosis, supports a noncontrast computed tomography attenuation value of 10 HU as a safe cutoff value to differentiate adrenal adenomas/hyperplasias from nonadenomas.

MeSH terms

  • Adenoma / diagnostic imaging*
  • Adolescent
  • Adrenal Gland Neoplasms / diagnostic imaging*
  • Adrenocortical Hyperfunction / diagnostic imaging*
  • Adult
  • Diagnosis, Differential
  • Female
  • Humans
  • Male
  • Middle Aged
  • Retrospective Studies
  • Tomography, X-Ray Computed