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.