MRI-guided brain tumor cryoablation in a rabbit model.

Abstract

PURPOSE: To report the results of an animal trial exploring the feasibility of minimally invasive MR imaging-guided rabbit brain tumor cryoablation with an argon-based cryo-unit. MATERIALS AND METHODS: VX2 tumor segments (0.96x0.96x50 mm) were implanted into parietal lobes of 26 New Zealand white rabbits. Seventeen rabbits were treated with cryoablation. Six rabbits were not treated and formed a control group. Cryoablation was achieved with a MR-compatible cryoablation unit using 1.47-mm cryoprobes in an open 0.23 Tesla (T) MRI scanner. The therapeutic response was evaluated with follow-up MRI and the corresponding histopathology. A 3.0 T MRI scanner was used for preoperative and postoperative follow-up imaging. Posttreatment imaging with subsequent endpoints was performed at 3, 7, 14, and 60 days after the treatment. RESULTS: Of 17 rabbits, 6 died on the first postoperative day. Histopathology revealed coagulation necrosis in samples from the 3rd, 7th, and 14th day, and reactive changes at 60 days, these findings were consistent with MRI. The longest survival time in the treatment group, 60 days (n=2), was considerably longer than the survival times in control group. CONCLUSION: Successful rabbit brain tumor cryoablation can be achieved using argon-based cryodevice under MRI guidance. The complication rate in this series was relatively high.