A comparison of electrophysiological microrecording versus automatic MR-based segmentation to determine subthalamic nucleus boundaries - Report - MDSpire
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A comparison of electrophysiological microrecording versus automatic MR-based segmentation to determine subthalamic nucleus boundaries
Comparing Electrophysiological Microrecording and Automated MRI Segmentation for STN Boundaries
Overview
This study compared intraoperative microelectrode recordings (MER) with automated MRI segmentation (Brainlab ElementsTM) to define subthalamic nucleus (STN) boundaries in Parkinson’s disease patients undergoing deep brain stimulation (DBS). Results showed good concordance between the two methods in electrode placement and optimal trajectory selection, with minimal mean differences in STN entry and exit coordinates.
Background
Deep brain stimulation targeting the subthalamic nucleus is an effective treatment for fluctuating Parkinson’s disease symptoms. Precise lead placement within the STN, especially its sensorimotor region, is critical for clinical benefit. Targeting methods include direct MRI visualization, indirect atlas-based approaches, and electrophysiological microelectrode recordings (MER), each with advantages and limitations. Automated MRI segmentation tools like Brainlab ElementsTM offer patient-specific anatomical atlases, potentially reducing the need for invasive MER, but require validation against electrophysiological data.
Data Highlights
Parameter
Value
Statistical Significance
Patients enrolled
78 (25 females, 53 males)
Age range
37-70 years (mean 59.3)
Disease duration
4-21 years (mean 10.6)
Total trajectories analyzed
344
Definitive electrodes implanted
156
Trajectories inside STN by both methods
269 (78.2%)
p = 0.017
Trajectories outside STN by both methods
47 (13.7%)
p < 0.0001
Inside STN by MER only
21 (6.1%)
p < 0.0001
Inside STN by ElementsTM only
7 (2%)
p < 0.0001
Concordance (Fleiss’ kappa) for electrode location
0.721 (95% CI 0.623-0.819)
Concordance for optimal trajectory choice
0.693 (95% CI 0.578-0.808)
Agreement on optimal trajectory
85.3%
p < 0.0001
Mean difference in STN entry point (MER vs MRI)
0.173 mm (95% CI −0.053 to 0.399)
Mean difference in STN exit point (MER vs MRI)
0.086 mm (95% CI −0.147 to 0.320)
Limits of agreement for entry point
−2.406 to 2.752 mm
Limits of agreement for exit point
−2.577 to 2.750 mm
Key Findings
Good overall concordance between MER and automated MRI segmentation in defining STN boundaries (Fleiss’ kappa 0.721).
High agreement (85.3%) in selecting the optimal electrode trajectory between neurologists using MER and neurosurgeons using MRI-based planning (Fleiss’ kappa 0.693).
Minimal mean differences in STN entry (0.173 mm) and exit points (0.086 mm) between the two methods, indicating close spatial agreement.
95% of measurements showed differences within ±2.75 mm for both entry and exit points, demonstrating acceptable limits of agreement.
Some discrepancies existed with 6.1% of trajectories identified inside STN by MER only and 2% by MRI segmentation only, highlighting complementary information.
Clinical Implications
Automated MRI segmentation with Brainlab ElementsTM provides a reliable, patient-specific method for STN boundary definition that closely aligns with electrophysiological MER data. This suggests that less invasive imaging approaches may reduce reliance on time-consuming and expertise-dependent MER without compromising targeting accuracy. However, combining both methods may optimize electrode placement and clinical outcomes in STN-DBS surgery.
Conclusion
The study demonstrates that automated MRI segmentation is a valid alternative to MER for defining STN boundaries in Parkinson’s disease DBS surgery, with good concordance and minimal spatial differences. Integrating these approaches may enhance surgical planning and efficiency.
References
Article Source 2023 -- Evaluating Electrophysiological Microrecording Against Automated MRI Segmentation for Defining Subthalamic Nucleus Boundaries
Aviva Abosch, M.D., Ph.D., a neurosurgeon at Baptist Health Miami Neuroscience Institute, part of Baptist Health Brain and Spine Care, was installed as the Esernia Endowed Chair in Surgical Treatment of Adult Epilepsy and Movement Disorders.
Baptist Health Foundation announced that it has received a $2 million donation from Anthony and Joyce Esernia to establish a new endowed chair at Baptist Health Miami Neuroscience Institute.
