Adrenal Washout Calculator (CT)
Adrenal CT washout criteria (Caoili 2002 / Szolar 1998)Computes absolute and relative percentage washout of an adrenal nodule on multiphase CT. Adenomas typically enhance briskly and wash out rapidly, meeting the 60% absolute or 40% relative washout thresholds.
Also searched as: adenoma · incidentaloma
Information
Incomplete input
- Missing required input: unenhanced attenuation; enhanced (60-75 s) attenuation; 15-minute delayed attenuation.
How this tool works
Dedicated adrenal CT washout analysis requires attenuation measurements on unenhanced, early enhanced (60-75 s), and 15-minute delayed images. The absolute percentage washout (APW) uses the unenhanced baseline, while the relative percentage washout (RPW) needs only the post-contrast values and is more sensitive when a true unenhanced series is unavailable. APW of at least 60% or RPW of at least 40% supports an adenoma; lower values are indeterminate and overlap with metastases, pheochromocytoma, and other non-adenomas. A homogeneous lesion measuring 10 HU or less on unenhanced CT already meets the lipid-rich adenoma criterion and generally needs no washout analysis. Hypervascular metastases and some pheochromocytomas can show adenoma-like washout, so results must be read with morphology, size, and clinical context.
References
- Caoili EM, et al. Adrenal masses: combined unenhanced and delayed enhanced CT. Radiology 2002.
- Szolar DH, Kammerhuber FH. Adrenal adenomas and nonadenomas: washout at delayed CT. Radiology 1998.
- Radiopaedia: adrenal washout.
Implemented from the cited published sources. Educational use only; confirm against current guidelines before clinical use.
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