Correlation Between Contrast-Enhanced Intraoperative Ultrasound Using Sonazoid and Histologic Grade of Resected Hepatocellular Carcinoma

OBJECTIVE. Our aim was to accurately assess the correlation between findings of contrast-enhanced intraoperative ultrasound using Sonazoid and histologic grade of hepatocellular carcinoma (HCC). SUBJECTS AND METHODS. We enrolled 239 consecutive patients who were undergoing surgery for HCC for this study. Because 33 extensively necrotic HCCs were excluded, a total of 374 histologically proven HCCs were detected in all resected specimens and were the study subjects (71 well-differentiated, 239 moderately differentiated, and 64 poorly differentiated HCCs). After a laparotomy and liver mobilization, contrast-enhanced intraoperative ultrasound in the harmonic mode was performed after a Sonazoid injection. The first minute was defined as the vascular phase, in which the vascularity of the 239 HCCs was assessed. After an approximately 15-minute delay, a thorough liver exploration was performed (Kupffer phase). Preoperative dynamic CT was routinely performed, and the findings were assessed for reference. RESULTS. The proportion of hypervascular tumors during the vascular phase tended to be lower among well-differentiated than among moderately and poorly differentiated HCCs (66% vs 80%, p = 0.058). The proportion of hypoechoic tumors during the Kupffer phase was significantly lower among well-differentiated than among moderately and poorly differentiated HCCs (54% vs 92%, p < 0.0001). In dynamic CT, the proportions of hypervascular tumors during the early phase and hypodense tumors during the late phase were significantly lower among well-differentiated HCCs than among moderately and poorly differentiated HCCs, respectively (early phase, 51% vs 87%, p < 0.0001; late phase, 59% vs 85%, p < 0.0001). CONCLUSION. Contrast-enhanced intraoperative ultrasound using Sonazoid is useful for estimating the histologic grade of HCC.