Computed tomographic (CT) volumetry of adrenal adenomas and the contralateral adrenal glands was found to have high discriminatory ability to identify autonomous cortisol secretion, according to the results of a study published in the Journal of Clinical Endocrinology & Metabolism.

Investigators assessed the discriminatory capacity of CT-derived, 3-dimensional (3D) adrenal volumetry as a radiologic tool to predict ACS in patients with unilateral, incidentally discovered adrenal adenomas.

Eligible study participants were aged 18 years and older, had a diagnosis of adrenal incidentaloma, and were consecutively treated and followed from August 2016 to May 2020. A pair of independent radiologists conducted 3D volumetric analysis of both the unilateral adrenal adenoma and of the contralateral adrenal gland. Autonomous cortisol secretion was defined as a morning adrenocorticotropic hormone (ACTH) level ≤15 pg/mL and cortisol level following a dexamethasone suppression test (DST) ≥1.8 μg/dL.


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A total of 149 patients (mean age, 58±11.4 years; 76% women) were included in the study. Participants had a mean DST of 1.86±2.9 μg/dL and a mean ACTH of 15.1 ± 8.4 pg/mL.

The post-dexamethasone cortisol level was correlated positively with adenoma diameter and volume, and it was inversely correlated with the volume of the contralateral adrenal gland. A negative correlation was identified between ACTH and adenoma diameter and volume, and a positive correlation was identified between ACTH and the volume of the contralateral adrenal gland.

The cortisol level following DST had the highest correlation with the adenoma volume/contralateral adrenal volume (AV/CV) ratio (r=+0.46, P <.001), and ACTH had an inverse correlation (r=-0.28, P <.001).

The researchers also assessed radiologic parameters to predict ACS using crude and adjusted logistic regression analysis. Predicted regression values were used to evaluate receiver operating characteristic (ROC) curves and estimate sensitivity and specificity of the models. Among the 4 significant radiologic parameters predicting autonomous cortisol secretion status, the AV/CV ratio had the highest odds ratio (OR, 1.40; 95% CI, 1.18-1.65) and area under the ROC curve (0.91; 95% CI, 0.86-0.96) for a diagnosis of autonomous cortisol secretion.

An AV/CV ratio ≥1 (48% of the cohort) identified autonomous cortisol secretion with a sensitivity of 97% and a specificity of 70%. An AV/CV ratio ≥3 (19% of the cohort) identified autonomous cortisol secretion with a sensitivity of 62% and a specificity of 95%.

Study limitations include the relatively small sample size and lack of follow-up to predict cardiometabolic outcomes. Also, most participants were women with unilateral adenomas, and the findings regarding the AV/CV ratio only apply to unilateral adenomas.

“[Computed tomographic] volumetry of adrenal adenomas and contralateral adrenal gland is a simple and low-cost method with excellent predictive capacity to identify [autonomous cortisol secretion],” concluded the study authors. “An AV/CV ratio ≥1, with high sensitivity and a very low false negative rate, could assist in the clinical decision to exclude incidental adenomas unlikely to exhibit hypercortisolism. The inclusion of this radiographic phenotyping could simplify the assessments and referrals for incidental adrenal adenomas and improve clinical care for this overlooked entity.”

Disclosure: One of the study authors declared affiliations with pharmaceutical companies. Please see the original reference for a full list of authors’ disclosures

Reference

Olmos R, Mertens N, Vaidya A, et al. Discriminative capacity of CT volumetry to identify autonomous cortisol secretion in incidental adrenal adenomas. J Clin Endocrinol Metab. Published online January 10, 2022. doi:10.1210/clinem/dgac005