GuidelineACR Incidental FindingsCT / MRIAdrenal Algorithm
Adrenal Incidentaloma
ACR Incidental Findings · Updated 2023 revision
Size, washout thresholds, and follow-up cadence for the incidental adrenal mass.
Bottom line
≤4 cm + benign features: no follow-up. Indeterminate: dedicated adrenal CT.
Applies to
Incidentally detected adrenal nodules on CT or MRI in adults
Does NOT apply to
Patients with known primary malignancy staged with dedicated adrenal protocol · Suspected pheochromocytoma with biochemical work-up already positive
Modality
CT / MRI
Evidence
ACR Incidental Findings White Paper
30-second summary
≤ 4 cm with benign features → no follow-up. Indeterminate → dedicated adrenal protocol CT with washout or chemical-shift MRI.
Overview
Size, washout thresholds, and follow-up cadence for the incidental adrenal mass.
Quick reference
Size / density — management
| Finding | Management |
|---|---|
| ≤ 4 cm, benign HU (< 10) or macro fat | No follow-up |
| ≤ 4 cm, indeterminate | Adrenal CT washout or CS-MRI |
| > 4 cm, no prior imaging | Endocrine work-up ± resection |
| Growth ≥ 5 mm/year | Consider resection |
Decision algorithm
Interactive
Adrenal Incidentaloma Algorithm
Work-up of the incidental adrenal mass discovered on abdominal CT.
Walk through algorithm
References
- OpenMayo-Smith WW et al. JACR 2017 — ACR Incidental Adrenal