BACKGROUND: Postoperative imaging is essential for verifying electrode location in patients undergoing deep brain stimulation (DBS). MRI offers better visualisation of brain targets, but concerns about adverse events have limited its use. Preoperative stereotactic MRI fused with a postoperative stereotactic CT, demonstrating the electrode position, is now widely used.
OBJECTIVES: The aims of this study were to: (1) evaluate the accuracy of image registration using Neuroinspire, and (2) undertake a systematic review of the literature on CT/MRI fusion techniques to ascertain the accuracy of other software packages.
METHODS: Twenty patients who underwent bilateral subthalamic nucleus DBS for Parkinson's disease were selected. The postoperative CT was registered and fused with the preoperative MRI using Neuroinspire. The position of each electrode tip was determined in stereotactic coordinates both in the (unfused) postoperative CT and the fused CT/MRI. The difference in tip position was used to evaluate the registration accuracy.
RESULTS: The mean error ± SD of CT/MRI fusion using Neuroinspire was 0.25 ± 0.15, 0.33 ± 0.26 and 0.46 ± 0.55 mm in lateral, anteroposterior and vertical axes. A systematic review suggested that CT/MRI registration with Neuroinspire is more accurate than that achieved with other tested CT/MRI fusion algorithms.
CONCLUSION: CT/MRI fusion for localisation of electrode placement offers an accurate, reliable and safe modality for assessing electrode location.