Clinical Utility of Noncontrast Computed Tomography Attenuation Value (Hounsfield Units) to Differentiate Adrenal Adenomas/Hyperplasias from Nonadenomas: Cleveland Clinic Experience


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.

Authors: Amir H. Hamrahian, Adriana G. Ioachimescu, Erick M. Remer, Gaspar Motta-Ramirez, Hari Bogabathina, Howard S. Levin, Sethu Reddy, Inderbir S. Gill, Allan Siperstein, Emmanuel L. Bravo
Keywords: Hounsfield unit, computed tomography attenuation value
DOI Number: 10.1210/jc.2004-1627      Publication Year: 2005

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