Introduction: There are few post-mortem brain studies of patients with previous deep brain stimulation (DBS) surgery, and most are histopathological and not magnetic resonance imaging (MRI) based. We aimed to correlate precisely defined microanatomic sites of brain stimulation with known outcomes of DBS to clarify the effects of stimulation of specific neuroanatomic structures and improve DBS targeting and outcomes.
Methods: We have preliminary data from scanning the subthalamic areas from two Parkinson’s disease (PD) DBS patients (four hemispheres) utilizing 17.6 T MRI scanner. The brains were dissected so that the specimens will fit into the 25 mm volume RF coil of the scanner, and then the imaging studies were performed in an attempt to reveal the relationship between the precise lead location with the surrounding structures. The utilized sequences were T1-, T2-, and diffusion weighted images.
Results: This MRI technique clearly showed the basal ganglia structures in the subthalamic area where clinical MRI scanners with 3 T or less magnetic fields do not. We observed that subthalamic nucleus (STN) DBS in two patients was effective despite being outside the dorsolateral “hot” zone. Specifically, one electrode was on the anterior border of the STN, and three other DBS electrodes were located 3 mm medial to the internal capsule, outside of the STN.
Conclusions: The electrical stimulation of the STN and the surrounding fiber systems in the subthalamic area produces variably beneficial modulation of the malfunctioning motor network in Parkinson’s disease. This novel new technology is a powerful tool to clarify the effects of stimulation of specific neuroanatomic structures and improve DBS targeting and outcomes.
Patient Care: The information from our study will add new insights to the current circuit theory, and will directly impact and improve current practice in DBS surgery especially targeting. Further, this information can be used for future DBS target areas and for other movement disorders.
Learning Objectives: By the conclusion of this session, participants should be able to:
1. Understand the current targeting strategies for STN DBS
2. Recognize importance of the preoperative imaging study
3. Understand the potential mechanisms of STN DBS for Parkinson’s disease