Adrenal CT Washout: Protocol, Formulas, Interpretation, and Pitfalls
Calculate absolute and relative adrenal washout correctly, understand traditional thresholds, avoid protocol and ROI errors, and report limitations clearly.
RadPhrases Editorial Team3 min read
Adrenal CT washout uses attenuation change between enhanced and delayed images to support characterization of selected adrenal lesions. Traditional criteria often use absolute percentage washout (APW) of at least 60% or relative percentage washout (RPW) of at least 40% on an appropriately timed protocol, but these values are not a stand-alone diagnosis of adenoma.
Clinical scope This guide is for radiology professionals. Apply current adrenal-incidentaloma guidance, lesion morphology, hormonal assessment, oncologic history, prior imaging, local protocol, and multidisciplinary judgment.