Undetermined focal liver lesions on gray-scale ultrasound in patients with fatty liver: Characterization with contrast-enhanced ultrasound

Background and Aim: The purpose of this study was to assess the clinical value and potential impact of contrast-enhanced ultrasound (CEUS) in the characterization of undetermined focal liver lesions (FLLs) in patients with fatty liver. Methods: Fifty-two patients (34 men, 18 women) with fatty liver with 67 FLLs (size range, 1-8.6 cm; mean, 4.1 +/- 3.1 cm) undetermined at baseline ultrasound (US) underwent contrast-enhanced US. CEUS examinations were analyzed by two experienced sonologists blinded to the final diagnosis. Readers evaluated by consensus the baseline echogenicity, the dynamic enhancement pattern in comparison with peripheral liver parenchyma. The final diagnosis was based on consensus interpreting of all examinations by another two expert observers with access to histological data. The characterization accuracy, sensitivity, and specificity of CEUS in characterizing the lesion as benign or malignant, and as the correct pathologic type, were analyzed. Results: After CEUS, two hemangiomas, three inflammatory pseudotumors, and one hepatocellular carcinoma were misdiagnosed. The overall characterization accuracy, sensitivity and specificity of CEUS were 91% (61/67), 91.7% (11/12), and 90.9% (50/55), respectively. Forty-three benign lesions were diagnosed as the correct pathologic type. The portal venous phase and late phase were important in the characterization of the lesions. The characterization accuracy had no relationship with the size of FLLs. Conclusion: CEUS can improve the characterization of undetermined FLLs arising from fatty liver.