Limited added value of contrast-enhanced ultrasound over B-mode for the subtyping of hepatocellular adenomas.

PURPOSE: To compare the features of hepatocellular adenoma subtypes (HCAs) in B-mode and contrast-enhanced ultrasound (CEUS).

METHOD: Thirty-three patients (31 women [94 %] and two men [6%], median age [Q1-Q3] 43.5 years old [35-51]) with 44 pathologically proven and subtyped HCAs (including 29 inflammatory HCAs [I-HCA] and 15 HNF1-α inactivated HCAs [H-HCA]) who underwent CEUS were included. The features of HCA on B-mode and CEUS were independently reviewed by two radiologists and compared between HCA subtypes.

RESULTS: I-HCAs were mostly hypoechoic (23/29, 79 %) or isoechoic (4/29, 14 %) with B-mode. Twelve of them (41 %) were heterogeneous. All H-HCAs except one demonstrated homogeneous hyperechogenicity (93 %) (p = 0.001). Moderate or marked liver steatosis was only observed in I-HCAs (12/29, 41 %) (p = 0.001). Arterial hyperenhancement was observed on CEUS in 27/29 (93 %) I-HCAs and in 14/15 (93 %) H-HCAs (p=0.98). Washout was present in 6/29 (21 %) I-HCAs and 1/15 (7%) H-HCAs (p=0.27). A total of 23/29 (79 %) I-HCAs and 15/15 (100 %) HCAs were homogeneous on portal and delayed phase acquisitions (p=0.04). The specificity for identifying an H-HCA was 100 % when the lesion was homogeneous and hyperechoic on B-mode, and the sensibility to rule out an H-HCA was 100 % if neither of these two features was present in a liver with obvious steatosis.

CONCLUSIONS: Most CEUS features, especially enhancement patterns, do not significantly differ between HCA subtypes. When HCA is suspected on CEUS, B-mode features should be considered, and a combination of lesion hyperechogenicity, homogeneity and the absence of obvious liver steatosis may be useful to distinguish H-HCAs from I-HCAs.