Objective To evaluate the safety and efficiency of ultrasound (US)-guided precise MWA assisted by artificial pleural effusion and/or ascites in hepatic neoplasms adjacent to high-risk structures based on a 3D preoperative planning system. Methods Twenty-five patients with hepatic neoplasms adjacent to high-risk structures were enrolled. CT images of all patients were reconstructed with 3D visualization software for preoperative planning. The puncture path and needle layout were estimated.

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... ded precise MWA assisted by artificial pleural effusion and/or ascites was performed. Patients were followed by clinical and imaging examinations at 3, 6, and 12 months after the MWA. Study outcomes including complications, liver function, AFP level, and ablation lesion volumes were evaluated. Results Thirty-two tumors in 25 patients underwent precise MWA. Except for 4 patients with tumors near the macrovascular, 21 patients received artificial pleural effusion and/or ascites, achieving a complete separation. Based on preoperative 3D planning, patients with tumors near the diaphragmatic dome underwent administration of artificial pleural effusion and ascites, while patients with tumors near the gastrointestinal tract or gallbladder received artificial ascites. Of the 32 tumors, 30 achieved complete ablation in the first MWA session, and 29 achieved conformal ablation with a safe boundary of 0.5-1 cm. No severe complications were observed. Only one tumor exhibited local progression. Moreover, serum levels of ALT, AST and AFP were significantly decreased during the follow-up period. Conclusion Based on the 3D preoperative planning system, US-guided precise MWA assisted by artificial pleural effusion and ascites, is a safe and effective tool to treat hepatic neoplasms adjacent to high-risk structures.