[Contrast-enhanced ultrasound in hepatic focal nodular hyperplasia]. / Le cas clinique du mois. L'échographie avec injection de produit de contraste dans l'hyperplasie nodulaire focale du foie.

The ultrasound contrast agent is composed by microbubbles of sulfur hexafluoride. It is now recognized to the characterization of liver lesions. Focal nodular hyperplasia (FNH) is a benign lesion of the liver. It is found in the majority of cases among women with a sex ratio 1M/8F, no typical clinical presentation or malignancy is described. When the liver lesion was found in B-mode ultrasound, injection of contrast can be realized immediately by the radiologist. The study of the lesion during the arterial, portal and late phases with the contrast-enhanced ultrasound allows the diagnosis of FNH with a specificity of 97%. In arterial phase, the prescence of a central artery and scarring, centrifugal progression of enhancement, a transient unenhanced zone and in portal and late phases, isoechogenicity compared to adjacent parenchyma are the main features of FNH described in the literature.