Grading of hypervascular hepatocellular carcinoma using late phase of contrast enhanced sonography - a prospective study.

BACKGROUND

Outcome of patients with hepatocellular carcinoma is influenced by their histological grade. Invasive biopsy of the lesions is the gold standard in this regard.

AIMS

We therefore analysed the diagnostic accuracy of contrast enhanced ultrasound for non-invasive grading of hypervascular hepatocellular carcinoma in liver cirrhosis.

METHODS

According to the tumour perfusion kinetics on contrast enhanced ultrasound two grading groups were prospectively defined: well-differentiated hepatocellular carcinoma (US-G1) and higher grade hepatocellular carcinoma (US-G2/G3). Immediately after contrast enhanced ultrasound-grading, biopsies of hepatocellular carcinoma-lesions (n=95, 1.2-12.5 cm) were obtained and analysed for tumour grading (G). Descriptive statistics, sensitivity, specificity positive and negative predictive values, diagnostic likelihood ratios and interoperator reproducibility were calculated (κ).

RESULTS

Histologically 77 (81.1%) patients had G2-G3 and 18 (18.9%) had G1 tumours. Higher grade hepatocellular carcinoma showed more often a washout in the portal or late phase (p<0.0001). The sensitivity, specificity, positive predictive values and negative predictive values of contrast enhanced ultrasound for grading of hepatocellular carcinoma for all patients were 94% (CI: 72-99%), 95% (CI: 88-99%), 81% and 99% and for patients with tumours<5 cm 100%(95% CI: 79-100), 96% (95% CI: 80-99), 92% and 100%. Positive and negative diagnostic likelihood ratios' were 18 and 26 and 0.06 and 0, respectively. κ=0.941 (p<0.001).

CONCLUSIONS

Contrast enhanced ultrasound has a high diagnostic value and reproducibility for non-invasive grading of hypervascular hepatocellular carcinoma >1cm in patients with liver cirrhosis.