The real-time MR targeting guidance and monitoring cryoablation for 16 cases liver tumors

Objective: To describe the cryoablation of primary and secondary liver tumors by using a percutaneous approach and intraprocedural open-configuration magnetic resonance imaging monitoring and to assess the feasibility and safety of the procedure. Methods: Total 26 malignant tumors in 16 patients were performed with percutaneous cryoablation under the guidance of near real-time images of a 0.23 T open-configuration MR system mounted with ipath 200 optical tracking system. Cryoablation was performed using a high-pressure argon system(Cryo-Hit system) with a double freeze/thaw cycle. A 2 or 3 mm MR-compatible cryoprobe was guided into the target mass according to the size of tumors. Changing cryoprobe angle or multiple sites probing were performed if necessary. For depicting cryonecrosis areas, Gd-DTPA enhance MRI were acquired on 1.5 T MR scanner within 24 hours after ablation. MR-compatible puncture probe were used for particles inserted. Results: All procedures were carried out safely and accurately without any serious complications. Twenty-six cryoablations were performed for 26 tumors in 16 patients. Intraprocedural MRI enabled clear visualization of the cryoprobe and iceballs as band-like and ellipsoid-like regions of signal losses, respectively. Sharply marginated iceballs engulfed tumors. After 1-24 months following-up, CR was 5 cases, PR was 8 cases, PD was 3 cases, respectively. Conclusion: MR-guided percutaneous targeting intervention and monitoring cryoablation for liver tumor therapy are feasible and safety. (authors)