Regenerative nodules – Regenerative nodules develop in response to liver injury and are comprised of a proliferation of hepatocytes and surrounding stroma. They are typically seen in the setting of cirrhosis
Radiology: Regenerative nodules appear as round, well-defined nodules (usually in the thousands) present throughout the liver with surrounding fibrosis 5.
On post-contrast CT and MRI, regenerative nodules enhance similar to the normal liver parenchyma in both portal venous and hepatocellular/delayed phases, and thus may not be distinguishable in a cirrhotic liver. Arterial phase enhancement is generally absent or minimal, and will increase with the degree of dysplastic transformation and neo-vascularisation.
CT
Regenerative nodules are rarely visible on non-contrast CT unless they are siderotic (i.e. containing iron. Siderotic regenerative nodules are hyperdense to liver on precontrast imaging and become isodense to liver on post contrast phases