Abstract: Objective To explore the application of contrast-enhanced ultrasound to evaluate the efficacy of microwave ablation for the treatment of special site primary liver cancer. Methods Between June 2020 and June 2022, 70 patients with primary liver cancer at special sites confirmed by pathological examination were divided into a microwave ablation group (n=30) and a microwave ablation combined with absolute alcohol group (n=40) according to the treatment method. A retrospective study was carried out in these two groups of patients. At one month after surgery, contrast-enhanced ultrasound and enhanced CT were performed to evaluate the ablation effect and compare the incidences of complications in them. Results By contrast-enhanced ultrasound it was shown that 22 cases were completely ablated in microwave ablation group, and the complete ablation rate was 73.3%, while 38 cases were completely ablated in microwave ablation combined with absolute ethanol group, and the complete ablation rate was 95.0%. The difference between the two treatment methods was statistically significant (χ²=6.572, P=0.010). By enhanced CT it was shown that 21 cases were completely ablated in microwave ablation group, and the complete ablation rate was 70.0%, while 36 cases were completely ablated in microwave ablation combined with absolute ethanol group, and the complete ablation rate was 90.0%. The difference between the two treatment methods was statistically significant (χ²=4.534, P=0.033). However, there was no significant difference in the complete ablation rate between contrast-enhanced ultrasound and enhanced CT in microwave ablation group and microwave ablation combined with absolute alcohol group (χ²=0.082, 0.721, P=0.774, 0.396). In the microwave ablation group, there was 1 case of postoperative bleeding, 1 case of infection, 2 cases of bile leakage, 2 cases of abdominal fluid accumulation, and 1 case of peripheral organ injury. The total incidence rate of these complications was 23.3% (7/30); In the microwave ablation combined with anhydrous ethanol group, there was 1 case of postoperative bleeding, 2 cases of infection, 1 case of bile leakage, 4 cases of abdominal fluid accumulation, and 1 case of peripheral organ damage. The total incidence rate of complications was 22.5% (9/40). There was no statistically significant difference in the total incidence of complications between the two groups (P>0.05). Conclusion The application of microwave ablation combined with anhydrous ethanol in the treatment of primary liver cancer at special sites has significant effects, which improves the tumor ablation rate without increasing recurrence risk. Contrast enhanced ultrasound has a definite value in evaluating the ablation effect, which is equivalent to the efficacy of enhanced CT and should play a guiding role in clinical practice.

Key words: Primary liver cancer, Special parts, Contrast-enhanced ultrasound, Microwave ablation