Introduction: Optimal lead location is the critical factor for the outcome of DBS procedures. Intraoperative CT offers 3-dimensional verification of both micro-electrode and DBS lead placement during DBS surgery. The accuracy of ICT for DBS procedures has not been extensively studied .
Methods: DBS surgery was performed using the Leksell stereotactic G frame. The stereotactic coordinates of the ventral electrode contact of 25 DBS leads were determined on ICT and corresponding postoperative MRI and compared with the intended target coordinates. The resulting absolute differences in X (medial-lateral), Y (anterior-posterior) and Z (dorsal-ventral) coordinates (deltaX, deltaY and deltaZ) for both modalities were then used to calculate the Euclidian distance: square root(deltaX)²+(deltaY)²+(deltaZ)² ) which describes the accuracy in 3-dimensional space.
Results: For the ICT the (mean ± SD) absolute differences for X, Y and Z were 1.2 ± 0.85 mm, 0.98 ± 0.89 mm, 1.2 ± 1.06 mm, while the corresponding numbers for the MRI were 1.28 ± 0.86 mm, 1.36 ± 1.15 mm, 1.28 ± 0.86 mm. There was no significant difference in absolute distances, although ICT showed a trend towards a more dorsal lead position (p=0.05). The Euclidian distance for ICT was 2.64 ± 0.94 mm and 2.69 ± 1.15 mm for MRI (p=0.1).
Conclusions: The data suggest that ICT imaging of DBS leads is as accurate as post-operative MR imaging. ICT therefore is a reliable technique for intra-operative confirmation of lead placement. In addition, merging of ICT with preoperative MRI could potentially obviate the need for postoperative MRI, which is considered to be the gold standard to verify DBS lead placement.
Patient Care: 1)intraoperative ICT offers 3d evaluation of lead location and with anatomical verification after merging it to MRI, both can contribute to more accurate placement.
2)ICT could potentially obiate the need for postoperative MRI, resulting in less patient burden.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) describe the usage of ICT in DBS surgery 2) describe the equivalent lead localization on ICT compare to postoperative MRI 3) discuss possible benefits of implementation of ICT in DBS surgery