Focal liver lesion: nonlinear contrast-enhanced ultrasound imaging

Enhancement Patterns of Benign Focal Lesions

Focal Nodular Hyperplasia

Focal nodular hyperplasia is the second most common benign solid hepatic focal lesion. It occurs more commonly in young women than men (2-4 females to 1 male ) in the third and fifth decade (Volk et al., 2001), and  is a hypervascular hyperplasic lesion caused by preexisting vascular malformation. It is characterized by abnormally arranged hepatocytes, Kupffer’s cells, bile duct elements and vascularized fibrous septae. A peripheral pseudo capsule and a central or eccentric fibrous scar radiating to the periphery and containing arteries can be found. Usually it is smaller than 5 cm (Ros et al., 2001). On conventional US iso-, hypo-, hyper-echoic appearances may be found. A hypo-echoic stellate central scar can be identified in 18% of cases. Color Doppler can depict flow signals within the central and radiating vessels (Tanaka et al., 1990). Contrast- enhanced ultrasound may show typical and atypical features as described below (Migaleddu et al., 2004, Catalano et al., 2005).

  • Typical features:
    • Arterial phase: hyper-enhancing complete;
    • Portal Vein phase: hyper-enhancing;
    • Parenchymal phase: iso- hyper-enhancing.
  • Additional features:
    • Arterial phase:, early “central spider” or "spoke wheel” arteries and centrifugal filling , feeding artery;
    • Portal Vein phase: hypo- enhanced central scar;
    • Parenchymal phase: hypo-enhanced central scar.

Case A-2.1

Focal liver lesion between 2-3 segment, solid hypoechoic, show central vessels at color-power Doppler. In arterial and portal phase show an hyper-enhancing complete, and in parenchymal phase iso-echoic enhancement to the rest of parenchyma. C.R: INF

Case A-2.2

In arterial phase early presence of a center-lesion vessel and aspect to spider central sign. In progressive portal phase enh of centrifugal type. In late parenchymal phase light hyper-enhancement regarding the surrounding parenchyma. C.R: INF