MR-guided microwave thermocoagulation therapy of liver tumors: initial clinical experiences using a 0.5 T open MR system

Advanced computer assistance for magnetic resonance-guided microwave thermocoagulation of liver tumors

RATIONALE AND OBJECTIVES

The purpose of this study was to utilize computer assistance effectively for both easy and accurate magnetic resonance (MR) image-guided microwave thermocoagulation therapy of liver tumors.

MATERIALS AND METHODS

An open configuration MR scanner and a microwave coagulator at 2.45 GHz were used. Navigation software, a 3D Slicer, was customized to combine fluoroscopic MR images and preoperative MR images for the navigation. New functions to display MR temperature maps with simple parameter setting, and to record and display the coagulated areas by multiple microwave ablations in the 3-dimensional space (footprinting), were also introduced into the software. The VGA signal of the computer display was directly transferred to the surgeon's monitor.

RESULTS

The customized software could be used for both accurate image navigation and convenient and easy temperature monitoring. Because repeated punctures and ablations are usually required in this procedure, the footprinting function made targeting of the tumors both easy and accurate and was quite effective in achieving the necessary and sufficient treatment. Furthermore, clear display on the surgeon's monitor, which was obtained by direct transfer of the VGA signal, enabled precise image navigation.

CONCLUSION

The newly developed computer assistance was quite useful and helpful for this MR-guided procedure.

New assistive devices for MR-guided microwave thermocoagulation of liver tumors

RATIONALE AND OBJECTIVES

The purpose of this study was to develop and test new assistive devices to aid in the performance of safe, easy, and accurate microwave thermocoagulation therapy guided by magnetic resonance (MR) imaging.

MATERIALS AND METHODS

An open-configuration MR imager with an optical tracking system for image plane control and a microwave coagulator operating at 2.45 GHz were used. Liver tumors were percutaneously punctured under the guidance of MR images and ablated. Handpiece adapters were then prepared for the optical tracking system. An MR-compatible endoscopic system also was used. Navigation software was installed and customized. These devices were combined to provide near-real-time MR image-guided navigation during thermocoagulation therapy for liver tumors.

RESULTS

The handpiece adapters improved the flexibility of approaches for percutaneous puncture of tumors. The MR-compatible endoscope was used as a thoracoscope, and tumors just below the diaphragm were safely and easily punctured through the diaphragm. The customized navigation software displayed near-real-time MR images together with two reformatted images (on the same plane and on a perpendicular plane) from the registered high-resolution three-dimensional data, enabling accurate MR imaging navigation.

CONCLUSION

These new assistive devices made it easier to perform safe, easy, and accurate MR-guided thermocoagulation therapy of liver tumors.