MRI Free Targeting of Deep Brain Structures in the Anterior Cingulate Cortex Using Facial Landmarks

Emerging neurostimulation methods aim to selectively modulate deep brain structures. Guiding these therapies has presented a substantial chal- lenge, since imaging modalities such as MRI limit the spectrum of benefi- ciaries. In this study, we assess the guidance accuracy of a neuronavigation method that does not require taking MRI scans. The method is based on clearly identifiable anatomical landmarks of each subject's face. We com- pared this technique to the ideal case, MRI-based nonlinear brain registra- tion, and evaluated the accuracy of both methods across ten targets located in deep brain structures: 8 targets in the anterior cingulate cortex as well as the anterior commissure and posterior commissure. Compared with the ideal case, the average localization error of the MRI-free method was 5.75 ± 2.98 mm (mean ± SD). These findings suggest that this method may provide suf- ficient compromise between practicality and the accuracy of targeting deep brain structures.