the Arterial Enhancement Fraction (AEF) depicts the hemodynamic changes associated with diffuse liver disease. It can detect changes in the balance between hepatic arterial and portal venous flow.
Exam: cross-sectional dynamic CT images with injection of a nonionic contrast material
The hepatic arterial phase was measured at 17-19 seconds after venous injection, while the portal venous phase was measured 30-33 seconds after the injection.
Parameters:
(1) hepatic arterial enhancement phase in Hounsfield Units (HU)
(2) portal venous enhancement phase in HU
(3) unenhanced phase in HU
arterial enhancement fraction =
= ((arterial phase) - (unenhanced phase)) / ((portal venous phase) - unenhanced phase)) * 100
In a normal patient the arterial enhancement fraction is 28.5 +/- 8.2%.
In Child-Pugh grade C cirrhosis the AEF is 43.4 +/- 16/1%.
In acute hepatitis the AEF 51.1 +/- 15%.
