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Accurate localization of deep brain stimulation electrode contacts using extended Hounsfield unit computed tomography
Naomi I Kremer1, Arjen L J van Hulzen2, Katalin Tamasi3,4
1Department of Neurosurgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. n.i.kremer@umcg.nl.
Objectives:
Accurate localization of deep brain stimulation (DBS) electrodes is critical for effective therapy. Conventional CT is widely used postoperatively but fails to delineate individual electrode contacts due to metallic artifacts. This study aimed to evaluate extended Hounsfield unit (EHU) CT - using an expanded scale up to 40,000 HU- for accurate localization of individual DBS electrode contacts.
Materials And Methods:
This retrospective study included 29 patients (58 DBS electrodes) who underwent DBS implantation. Postoperative imaging comprised both conventional CT and EHU-CT reconstructions. Two independent raters localized electrode contacts using a standardized protocol. Inter-method and inter-rater agreement were quantified using intraclass correlation coefficients (ICCs) and Euclidean distances. Qualitative assessments of contact visibility were also performed.
Results:
Quantitative analysis showed near-perfect agreement between EHU-CT and conventional CT (ICC ≈ 1), with high inter-rater consistency. However, qualitative evaluation revealed superior contact visualization with EHU-CT: all contacts were clearly identifiable in 100% of cases, while conventional CT consistently failed to distinguish individual contacts due to blooming artifacts. Conventional CT localizations were also sensitive to window-level adjustments, particularly along the z-axis.
Conclusion:
EHU-CT enables consistent and direct visualization of individual DBS contacts and provides a robust alternative to conventional CT. Its reduced sensitivity to display settings and improved interpretability may enhance intra-operative decision-making and postoperative programming, supporting more reliable DBS workflows.
Key Points:
Question Accurate deep brain stimulation (DBS) electrode localization is crucial for optimal intra-operative adjustments and outcomes, yet conventional CT is hindered by metallic artifacts limiting individual contact visualization. Findings Extended Hounsfield unit (EHU)-CT and conventional CT showed near-perfect agreement in electrode localization, but EHU-CT provided clearly superior visualization of individual electrode contacts. Clinical relevance By enabling direct visualization of individual contacts through an extended Hounsfield scale, EHU-CT can improve intra-operative decision-making and postoperative programming, potentially enhancing DBS localization accuracy and patient outcomes.
