Target definition and trajectory optimization for interactive MR-guided biopsies of brain tumors in an open configuration MRI system

We present an imaging strategy for planning and guiding brain biopsies in a n open configuration MR system. Preprocedure imaging was performed in a 1.5 -T MR system and was designed to provide, in a clinically efficient manner. high resolution anatomical and functional/physiologic information for prec ise definition and tissue characterization of the target, aiming at optimiz ation of the biopsy trajectory for planning a safe and accurate procedure. The interventions were performed in a .5-T open bore magnet, and imaging wa s optimized to provide the imaging quality and temporal resolution necessar y for performing the procedure interactively in near real time. Brain biops ies of 21 patients were performed in a 10-month period. Segmentation and su rface rendering analysis of the lesions and vascular structures and dynamic MR perfusion and cortical activation studies provided an efficient and com prehensive way to appreciate the relationship of the target to surrounding vital structures, improved tissue characterization and definition of the tu mor margins, and demonstrated the location of essential cortex, allowing ap propriate placement of the burr hole and choice of optimal trajectory. Inte ractive protocols provided good visualization of the target and the interve ntional devices and offered the operator real-time feedback and control of the procedure. No complications were encountered. Advanced methods of image acquisition and processing for accurate planning of interventional brain p rocedures and interactive imaging with MR guidance render feasible the perf ormance of safe and accurate neurointerventional procedures.