Real time elastography - a non-invasive diagnostic method of small hepatocellular carcinoma in cirrhosis.

Background: Small nodules (under 3 cm) detected on ultrasound (US) in cirrhotics represent the most challenging category for noninvasive diagnosis of hepatocellular carcinoma (HCC).
Aim: To evaluate real-time sonoelastography as a noninvasive tool for the diagnosis of small HCC nodules in cirrhotic patients.
Methods: 42 cirrhotic patients with 58 nodules (1-3 cm) were evaluated with real-time elastography (Hitachi EUB-6500); the mean intensity of colors red, blue, green were measured using a semi-quantitative method. Analysis of histograms for each color of the sonoelastography images was performed for quantifying the elasticity of nodule tissue in comparison with the cirrhotic liver tissue. AUROC curves were constructed to define the best cut-off points to distinguish malignant features of the nodules. Univariate and multivariate logistic regression analysis was performed.
Results: 595 sonoelastography images from 42 patients (25 men; 17 women) were analyzed. The mean age was 56.4 +/- 0.7 years and 69% patients were in Child-Pugh class A, 19% class B, 11% class C. For the mean intensity of green color AUROC=0.81, a cut-off value under 108.7 being diagnostic for HCC with a Sp=91.1%, Se=50%, PPV=92.1%, NPV=47.1%. Mean intensity of blue color proved to be an excellent diagnostic tool for HCC (AUROC=0.94); for a cut-off value greater than 128.9, Sp=92.2%, Se=78.9%, PPV=95.4%, NPV=68%. Independent predictive factors of HCC for a small nodule in cirrhotic patients were: blue color over 128.9 at sonoelastography and hypervascular appearance at Doppler US.
Conclusions: US elastography is a promising method for the non-invasive diagnosis of early HCC. Blue color at elastography and hypervascular aspects are independent predictors of HCC.