Article
Correlation between DTI-based fiber tracking and neurological deficits
Korrelation neurologischer Defizite mit Diffusions-Tensor-Bildgebung
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Published: | April 11, 2007 |
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Objective: Functional neuronavigation has become a widely used and standardized tool in neurosurgical operations in cortical areas. The implementation of diffusion tensor imaging (DTI)-based fiber tracking has been shown to be useful in the visualization of the pyramidal tract in patients with subcortical lesions. The aim of this study is to investigate the correlation between diffusion tensor based fiber tracking and neurological outcome.
Methods: 53 patients with supratentorial gliomas of all WHO grades were examined with a 1.5T MR scanner. A single-shot, spin-echo diffusion weighted echo planar imaging sequence was measured for DTI. Fiber tract seeding was based on a multiple region of interest (ROI) approach. A tensor deflection algorithm was used for tracking. Finally, a model of the pyramidal tract on both sides was created. Two subgroups of patients were set up based on the presence of a neurological deficit (with paresis n=16, without n=37). The total amount of reconstructed fibers in the right and left pyramidal tract was measured in each group. FA and ADC values in the ROIs, as well as of the whole reconstructed fiber bundle were calculated. Differences between the right and left pyramidal tract were statistically tested for significance.
Results: Comparing both sides of the pyramidal tract revealed a significantly reduced number of reconstructed fibers on the side of the lesion in the group with neurological deficits (reduction by 75% from 139 to 54). Fractional anisotropy (FA) of the whole fiber bundle was also significantly reduced (0.492 vs. 0.534); comparison of the apparent diffusion coefficients (ADC) did not show a difference. In the group without paresis, there were no differences between the affected and non-affected side. The number of reconstructed fibers, FA value (whole fiber as well as in the ROIs) was also significantly reduced when comparing the affected pyramidal tracts in both groups.
Conclusions: Loss of neurological function correlates with decreased overall fractional anisotropy in the reconstructed fiber bundles representing the pyramidal tract.