Article
Diffusion Kurtosis Fiber Tractography of the Arcuate Fascicle
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Authors
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Miriam Bopp
- Universitätsklinikum Marburg, Klinik für Neurochirurgie, Marburg, Deutschland
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Julia Arhelger
- Universitätsklinikum Marburg, Klinik für Neurochirurgie, Marburg, Deutschland
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Barbara Carl
- Universitätsklinikum Marburg, Klinik für Neurochirurgie, Marburg, Deutschland
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Christopher Nimsky
- Universitätsklinikum Marburg, Klinik für Neurochirurgie, Marburg, Deutschland
| Published: | June 9, 2017 |
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Outline
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Objective: Nowadays, Diffusion Tensor Imaging (DTI) and DTI-based fiber tractography (DTI-FT), as available in commercial neuronavigation systems, is used to outline major white matter tracts. Thereby, spatial extent of white matter tracts is often underestimated, due to several aspects of image acquisition and image processing. The tensor model itself is not capable of resolving multi fiber populations, as present in at least one third of the brain, only modeling Gaussian distributed diffusion patterns. More sophisticated diffusion models overcome the limitations of the tensor model, but in most cases are not applicable in clinical practice due to extensive image acquisition times. Diffusion Kurtosis Imaging (DKI), modeling also non-Gaussian diffusion properties, uses multi-shell diffusion imaging doubling acquisition times to overcome limitations of the tensor model.
Methods: To evaluate the impact of DKI-FT under clinical time constraints we analyzed fiber tractography results of the arcuate fascicle, relevant in language production and processing, using DTI-FT and DKI-FT in 20 healthy volunteers (mean age: 25.50± 2.06, male/female: 10/10) and 6 glioma patients. For every volunteer and patient MR image data was acquired at a 3T Trio MRI System (Siemens, Erlangen, Germany) including an echo planar imaging sequence with voxel size 2x2x2mm³, 30 diffusion encoding gradients, b-values: 0, 1000 and 2000 s/mm² and acquisition time of 9 minutes. Image data was processed using the Diffusion Kurtosis Estimator and TrackVis.
Results: Results differed for DTI-FT and DKI-FT. In all volunteers DKI-FT outlined more solid and compound white matter tracts in contrast to DTI-FT with tract volumes of 3.23±1.25 cm³ vs. 2.58±1.28 cm³ (p=0.04). In 4 out of 6 patients DKI-FT outlined more solid tracts with tract volumes of 3.63±1.43 cm³ vs. 3.21±1.01 cm³. In 2 cases the arcuate fascicule could only be visualized anatomically plausible using DKI-FT, whereas DTI-FT failed to outline the tracts at all.
Conclusion: DKI-FT shows promising results in order to visualize major white matter tracts in close vicinity to brain lesions with short imaging sequences applicable under clinical time constraints.
