Evaluating indirect subthalamic nucleus targeting with validated 3-tesla magnetic resonance imaging

Indirect targeting of the subthalamic nucleus (STN) is commonly utilized at deep brain stimulation (DBS) centers around the world. The superiority of either midcommissural point (MCP)-based or red nucleus (RN)-based indirect targeting remains to be established.

The location of the STN was determined and statistically compared to MCP- and RN-based predictions in 58 STN DBS patients, using a validated 3-tesla MRI protocol. The influence of additional neuroanatomical parameters on STN midpoint location was evaluated. Linear regression analysis was utilized to produce an optimized MCP/RN targeting model. Targeting coordinates at 1.5 T were compared to results at 3 T.

Accuracy and precision for RN-based targeting was superior to MCP-based targeting to predict STN midpoint location for each coordinate dimension (p < 0.01 and p < 0.05, respectively). RN-based targeting was statistically equivalent to an optimized regression-based targeting strategy incorporating multiple neuroanatomical parameters, including third-ventricle width and overall brain size. RN-based targeting at 1.5 T yielded equivalent coordinates to targeting at 3 T.

RN-based targeting is statistically superior to MCP-based STN targeting and accommodates broad variations in neuroanatomical parameters. Neurosurgeons utilizing indirect targeting of the STN may consider favoring RN-based over MCP-based indirect targeting methods.