Changing paradigms in evaluating adrenal incidentalomas: Bayesian evaluation of [18F]Fluorodeoxyglucose positron emission tomography use, honed on adrenocortical carcinoma.

We present the diagnostic performance of [18F]Fluorodeoxyglucose positron emission tomography (FDG PET) for adrenal incidentalomas based on lesion size and unenhanced computed tomography (CT) density in Hounsfield units (HU), following current literature and guidelines. A 20 HU cutoff can be applied to differentiate potentially benign from malignant lesions, particularly in ruling in or out adrenocortical carcinoma. While FDG PET provides valuable metabolic information, its likelihood ratios for a positive (LR+) or negative (LR-) result do not exceed the robust diagnostic thresholds of > 10.0 or < 0.1, respectively. This suggests that positron emission tomography alone is insufficient for definitive characterization and should be integrated with CT or magnetic resonance imaging to leverage their complementary anatomical and functional imaging strengths for optimal diagnostic accuracy.