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CT/MR image fusion in the postoperative assessment of electrodes implanted for deep brain stimulation
Ruth L O'Gorman1, Josef M Jarosz, Michael Samuel
1Department of Neuroradiology, King's College Hospital, London, UK. r.o'gorman@iop.kcl.ac.uk
Background/Aims:
Stereotactic postoperative imaging is essential for verification of the position of electrodes implanted for deep brain stimulation (DBS). MRI offers superior visualisation of the DBS targets relative to CT, but previous adverse incidents have heightened concerns about risks of postoperative MRI. Preoperative MRI fused with postoperative CT offers an alternative method for evaluating electrode position, but before this method can be clinically applied, the image registration accuracy must be established. The purpose of this study was to quantitatively assess the accuracy of three different image registration and fusion methods.
Methods:
Preoperative stereotactic MRI and postoperative stereotactic CT were acquired from 20 patients under- going DBS surgery (35 electrodes in total). The postoperative CT was registered and fused with the preoperative MRI, using three different registration algorithms. 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 between the CT and fused CT/MRI was used to evaluate the registration accuracy.
Results:
The mean error along the lateral, anteroposterior, and vertical axes was 0.5, 0.5, and 1 mm, respectively.
Conclusions:
CT/MRI fusion provides a safe, practical technique for postoperative identification of DBS electrodes.
Insights
Image fusion of preoperative MRI and postoperative CT accurately verifies deep brain stimulation (DBS) electrode placement. This CT/MRI fusion technique offers a safe and practical method for postoperative identification of DBS electrodes.
Area of Science:
- Neurosurgery
- Medical Imaging
- Biomedical Engineering
Background:
- Stereotactic postoperative imaging is crucial for verifying deep brain stimulation (DBS) electrode placement.
- MRI provides superior visualization of DBS targets compared to CT, but safety concerns exist.
- Preoperative MRI fused with postoperative CT is a potential alternative for evaluating electrode position.
Purpose of the Study:
- To quantitatively assess the accuracy of three different image registration and fusion methods for CT/MRI fusion.
- To establish the clinical applicability of preoperative MRI fused with postoperative CT for DBS electrode verification.
Main Methods:
- Acquired preoperative stereotactic MRI and postoperative stereotactic CT from 20 patients undergoing DBS surgery (35 electrodes).
- Registered and fused postoperative CT with preoperative MRI using three distinct registration algorithms.
- Determined electrode tip positions in stereotactic coordinates on both unfused CT and fused CT/MRI to evaluate registration accuracy.
Main Results:
- The mean error in electrode tip position was evaluated across lateral, anteroposterior, and vertical axes.
- Mean errors were 0.5 mm (lateral), 0.5 mm (anteroposterior), and 1 mm (vertical).
Conclusions:
- CT/MRI fusion is a safe and practical technique for the postoperative identification of DBS electrodes.
- This method enhances the verification of electrode placement in deep brain stimulation surgery.
