MR-compatible laparoscope with a distally mounted CCD for MR image-guided surgery

Objects: We have developed a new MR-compatible laparoscope that incorporates a distally mounted charge-coupled device (CCD). The MR-compatibility and feasibility of laparoscopy using the new laparoscope were evaluated during MR image-guided laparoscopic radiofrequency ablation therapy (RFA). Materials and methods: MR compatibility of the laparoscope was investigated in terms of MR image artifact caused by electromagnetic interference (EMI) and susceptibility. MR images were obtained using spin echo and gradient echo pulse sequences with a 0.3 T open MRI unit. We performed an in vivo experiment with MR image-guided laparoscopic RFA on three pigs; near real-time MR images and 3-D navigation were possible using intraoperative MR images. Agarose gel was injected into the pigs' livers as puncture targets; the diameter of each target was approximately 20 mm. Results: Artifacts resulting from EMI were not found in phantom experiments. MR image-guided laparoscopic RFA was successfully performed in all procedures. Both the laparoscopic vision and near real-time MR images were clear. No artifact was detected on the MR images and the surgeon was able to confirm the true position of the probe and target during treatment using the near real-time MR images. Conclusion: Laparoscopic surgery is feasible under intraoperative MR image-guidance using a newly developed MR-compatible laparoscope with a distally mounted CCD.