Adrenal "incidentaloma"

1.5 cm incidental adrenal nodule, with attenuation of 26 HU on routine CT is indeterminate. Per ACR white paper, a 12 month follow-up CT/MR should be considered, given that the nodule is homogeneous and low-density.

Virtual non-contrast shows attenuation of -7 HU, confirming benign adenoma.

A true non-contrast exam was performed 6 months later, which shows nodule is stable with an attenuation of -10 HU. A virtual non-contrast scan can, in most situations, substitute for a true non-contrast scan.

Conventional CT with indeterminate nodule in left adrenal gland (yellow arrow)

Virtual non-contrast with attenuation of -7 HU, diagnostic of a benign adenoma

Follow-up true non-contrast CT shows nearly identical attenuation