Diagnosis of Small Hepatic Nodules Detected by Surveillance Ultrasound in Patients with Cirrhosis: Comparison Between Contrast-enhanced Ultrasound and Contrast-enhanced Helical Computed Tomography

Aim: To investigate the diagnostic value for the diagnosis of small (1-2 cm) hepatic nodules detected by surveillance ultrasound in patients with cirrhosis using contrast-enhanced ultrasound (CEUS) compared with that of contrast-enhanced helical computed tomography (CECT).

Methods: Seventy-two liver cirrhosis patients with 103 small hepatic nodules (1-2 cm) detected by surveillance ultrasound were enrolled in the present study. All patients underwent CEUS with SonoVue as well as CECT. Nodules which appeared by contrast enhancement during the arterial phase and contrast wash-out during the late phase on CEUS or CECT were diagnosed as malignant (hepatocellular carcinoma [HCC]). Histopathology obtained from biopsy or surgery served as the gold standard.

Results: According to the above diagnostic criteria, the sensitivity (i.e. rate of correct diagnosis of HCC) was 91.1% (51/56 HCC) for CEUS and the specificity (i.e. the rate of correct exclusion of HCC) was 87.2% (41/47 regenerative nodules [RN]).Therefore, the diagnostic accuracy of CEUS was 89.3% (92/103 all nodules). Using the same diagnostic criteria, the sensitivity, specificity and accuracy of CECT were 80.4% (45/56 HCC), 97.9% (46/47 RN), and 88.4% (91/103 all nodules). Overall, there was no significant difference between CEUS and CECT in the diagnostic confidence of small hepatic nodules. Eighty-six nodules (45 HCC and 41 RN) were correctly diagnosed by both modalities and six (five HCC and one RN) were misdiagnosed by both.

Conclusion: The ability of CEUS in the characterization of small nodules (1-2 cm) detected by surveillance US in patients with liver cirrhosis is similar to that of CECT.