What is the expected enhancement pattern of focal nodular hyperplasia during CT arterial phase?

Focal nodular hyperplasia (FNH) typically exhibits a characteristic pattern of enhancement on imaging studies, particularly on a CT scan during the arterial phase. In patients with FNH, the enhancement pattern is defined by the presence of a central scar. Initially, during the arterial phase of a CT scan, a central area of enhancement occurs followed by peripheral enhancement, which can occur in the later phases.

This means that the central scar enhances first because it is supplied by arterial blood, while the surrounding liver tissue and the rest of the lesion enhance more slowly, resulting in a central to peripheral enhancement pattern. This characteristic is important for radiologists and surgeons to identify FNH accurately and differentiate it from other liver lesions such as hepatic adenomas or malignancies.

The enhancement pattern is critical because it helps inform the clinical approach and management of the lesion, indicating that FNH is usually a benign condition that often does not require surgical intervention unless symptomatic. Understanding this enhancement pattern helps in reducing unnecessary procedures and focusing on the appropriate management for patients.