Periportal low attenuation at CT in childhood.

Periportal low attenuation, defined as a low-attenuation rim around the portal vein and its branches that is seen on contrast material-enhanced computed tomographic (CT) scans, has been described in a variety of conditions in adults. The authors reviewed the appearance of periportal low attenuation on CT scans of 30 children. An association was found between a rim of low attenuation and hepatic trauma, hepatic transplantation, malignancy (undifferentiated hepatoblastoma, juvenile chronic myelogenous leukemia), and generalized hepatic disorders (acute hepatitis and congenital hepatic fibrosis). The possible mechanisms for development of periportal low attenuation include periportal tracking of blood, obstructive lymphedema, tumor infiltration, perivascular inflammation, or bile duct proliferation.