MRI-Guided Laser Ablation of Liver Tumors

Abstract

Percutaneous thermal ablation has become a viable option for locoregional control of localized hepatic malignancy. Commonly used ablative technologies include radiofrequency, microwave, and cryoablation. The use of MRI to guide and monitor these ablation procedures is associated with a considerably more refined technique primarily due to the ability of MRI to monitor the thermal effects of tissue heating as they occur. As such, MRI facilitates a tailored approach to treatment based on the actual visualization of individual tumor response. This approach represents a fundamental conceptual departure from the current standard CT- and ultrasound-guided ablations where amount and duration of deployed energy follow a predetermined “recipe” based on vendor’s recommendation and user’s experience. In this chapter, we introduce the readers to the basics of laser/tissue interactions during ablation. We then elaborate on the multifaceted role of MRI during liver ablation and how it contributes to creating a new refined approach to these procedures. We build on this background to transition to the rationale of choosing laser energy for ablation and how it best suits the MRI environment. We then describe the interventional MRI suite setup for liver laser ablation and conclude with a detailed step-by-step description of the various technical phases of guiding and monitoring a liver laser ablation procedure under MRI.