Novel Delivery System for Minimally Invasive MR Guided Neurological Interventions

Introduction The delivery of electrodes or other therapeutic agents to the brain frequently requires precision minimally invasive access. MR is ideally suited to this application and high targeting accuracies have been reported when delivering deep brain stimulator (DBS) electrodes (1). Convection enhanced delivery (CED) is a promising technique for delivering drug and gene therapies to the brain (2). The technique uses continuous injection of a fluid containing the therapeutic agent and the positive fluid pressure actively convects the agent through the interstitial space. Thus, a point source infusion can be used to deliver the agent over volumes that encompass the targeted brain structures. This approach bypasses the blood brain barrier and allows the distribution of larger therapeutic agents that are unlikely to migrate significantly simply by diffusion. Intra-operative MR imaging has been used to monitor the delivery of therapeutic agents via CED (3), but with more invasive methods and limited targeting accuracy. We have developed a second generation delivery platform (Figure 1) that is capable of inserting DBS electrodes or infusion cannula’s for CED. We evaluate the targeting accuracy that can be achieved with this platform in phantoms and present its application to CEDbased delivery in a primate model of Parkinson’s disease.