ESM-CT: a precise method for localization of DBS electrodes in CT images

Area of Science:

• Neurosurgery
• Medical Imaging
• Neurology

Background:

• Deep brain stimulation (DBS) for Parkinson disease shows variable outcomes potentially due to imprecise electrode placement.
• Accurate localization of subthalamic nucleus DBS electrodes is critical for understanding treatment efficacy.
• Existing methods for DBS electrode localization may lack precision or robustness.

Purpose of the Study:

• To develop and evaluate a semi-automated method, Electrode Shaft Modeling in CT images (ESM-CT), for precise DBS lead and contact localization.
• To assess the sensitivity, robustness, and replicability of the ESM-CT method.
• To investigate factors influencing DBS electrode position changes over time.

Main Methods:

• Developed Electrode Shaft Modeling in CT images (ESM-CT), a semi-automated technique for reconstructing DBS lead trajectories and contact locations.
• Evaluated ESM-CT's sensitivity to operator variability, image resampling, and test-retest replicability.
• Applied ESM-CT to 56 patients, analyzing electrode position changes between immediate post-implantation (DBS-CT) and later scans (DEL-CT).

Main Results:

• ESM-CT demonstrated high robustness to image resampling and test-retest replicability (∼0.2 mm).
• Systematic electrode displacement (rostro-ventral-lateral) was observed between DBS-CT and DEL-CT scans.
• Acquisition head angle was a significant factor influencing electrode displacement (p < 0.001), while subdural air volume showed a weaker correlation.

Conclusions:

• ESM-CT provides a robust and precise method for CT-based DBS contact localization.
• Head angle during CT acquisition is a critical determinant of electrode position and must be considered in localization schemes.
• The developed method offers improved accuracy compared to existing techniques, aiding in the study of DBS effects in Parkinson disease.