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65th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

11 - 14 May 2014, Dresden

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Deep brain stimulation: the variability of atlas based targets in relation to surrounding major fiber tracts

Meeting Abstract

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  • Judith Anthofer - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg
  • Kathrin Steib - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg
  • Max Lange - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg
  • Alexander Brawanski - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg
  • Juergen Schlaier - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Regensburg

Deutsche Gesellschaft für Neurochirurgie. 65. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Dresden, 11.-14.05.2014. Düsseldorf: German Medical Science GMS Publishing House; 2014. DocMI.06.03

doi: 10.3205/14dgnc308, urn:nbn:de:0183-14dgnc3080

Published: May 13, 2014

© 2014 Anthofer et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective: In essential tremor (ET) the main target for deep brain stimulation (DBS) is the thalamic ventralis intermedius nucleus (Vim). This target cannot be identified on conventional MR imaging. Therefore targeting depends on probabilistic coordinates derived from stereotactic atlases. The goal of our study was to investigate the variability of atlas based Vim targets in relation to surrounding major fiber tracts.

Method: In 10 patients who underwent DBS atlas based Vim targets were determined in both hemispheres. In addition, we have performed deterministic fiber-tracking based on diffusion tensor imaging (DTI) of the dentato-rubro-thalamic tract (DRTT), pyramidal tract (PT) and lemniscus medialis (LM) in all 20 hemispheres. Standardized regions of interest and DTI parameters were used in all cases. Subsequently we measured the distance from the atlas based Vim target to each tract along the medial/lateral (x-coordinate), anterior/posterior (y-coordinate) and superior/inferior axis (z-coordinate).

Results: 17 out of 20 DRTTs could be depicted with our standardized DTI/fiber tracking parameters. The PT and the LM could be displayed in all 20 hemispheres. The projection of the atlas based Vim target was found medial (n=2), lateral (n=4) and inside the DRTT (n=11) (concerning the x-coordinate) with a mean distance of 2.1mm. Along the y-axis atlas targets were positioned anterior (n=1), posterior (n=11) and inside the DRTT (n=5) with a mean distance of 2.8mm. 3 targets were located superior, 4 inferior and 10 inside the DRTT concerning the z-axis (mean distance = 2.0mm). A similar variability of positions of the atlas targets was found regarding the PT and LM.

Conclusions: We found a considerable variability of the locations of atlas-based target points of the ventralis intermedius nucleus in relation to neighboring major fiber tracts in individual patients. These results suggest that DTI based fiber tracking might help to individualize targeting to structures not directly visible on conventional MRI.