Article
Are two reference points sufficient for stereotactic coordinate transformation in deep brain stimulation?
Sind 2 Referenzpunkte für die Transformation von Atlaskoordinaten in stereotaktische Koordinaten auf dem Gebiet der tiefen Hirnstimulation ausreichend?
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Authors
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Jürgen Schlaier
- Neurochirurgische Klinik, Universitätsklinikum Regensburg, Regensburg
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P. Herzog
- Neurochirurgische Klinik, Zentralklinikum Augsburg, Augsburg
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P. Schödel
- Neurochirurgische Klinik, Universitätsklinikum Regensburg, Regensburg
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J. Warnat
- Neurochirurgische Klinik, Universitätsklinikum Regensburg, Regensburg
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M. Lange
- Neurologische Klinik, Universitätsklinikum Regensburg, Regensburg
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J. Winkler
- Neurologische Klinik, Universitätsklinikum Regensburg, Regensburg
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A. Brawanski
- Neurochirurgische Klinik, Universitätsklinikum Regensburg, Regensburg
| Published: | April 23, 2004 |
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Outline
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Objective
By transforming atlas coordinates into stereotactic frame coordinates, correction for rotational targeting error is required. We compared commercially available software based on 2 reference points (anterior and posterior commisure) with a correction algorhythm, developed by one of the authors (HP), which is based on an additional reference point in the midline of the brain. Our hypothesis was that there is a statistically significant and clinically relevant difference between the resulting coordinates, given that the 3-point-based algorhythm represents the mathematically most precise transformation.
Methods
We investigated 14 volunteers, who were fixed to the stereotactic frame by tight adhesive bands. Sagittal, coronal and axial T2 weighted MRI scans as well as MPRage sequences were performed. All MRI measurements were fused to the MPRage data set. The anterior and posterior comissure and one additional point (septum pellucidum) were determined on the axial T2 weighted images. Bilateral atlas coordinates for subthalamic nucleus (STN), globus pallidus pars interna (GPi) and nucleus ventralis intermedius (Vim) were transformed to stereotactic frame coordinates either without correction or by 2-point or 3-point correction. A total of 896 coordinates (x,y,z for STN, GPi and Vim in both hemispheres) were calculated.
Results
The difference between coordinates obtained from 3-point correction and 2-point correction ranged from 0-2,8mm (mean 0,24mm, standard deviation SD 0,33mm). Comparing the 3-point based transformation with the coordinates without any correction mean difference was 0,53mm (SD 0,48mm). The deviation of the 2-point coordinates from the 3-point transformation obtained coordinates was significantly less pronounced than the difference between the 3-point transformation and the coordinates without any correction of the rotational error (p<0,001)
Conclusions
In deep brain stimulation based on atlas-derived coordinates (Vim) rather than direct targeting on visible structures (STN,GPi) stereotactic planning should be performed with 3-point based transformation for correction of rotational errors.
