Artikel
Changes in fiber integrity, diffusivity and metabolism of the pyramidal tract adjacent to gliomas using quantitative diffusion tensor fiber tracking and MR spectroscopic imaging
Veränderung von Integrität, Diffusivität und Stoffwechsel der Pyramidenbahn bei Gliomen: Eine quantitative DTI- und MR-Spektroskopie-Studie
Suche in Medline nach
Autoren
-
O. Ganslandt
- Neurochirurgische Klinik, Universität Erlangen
-
C. Nimsky
- Neurochirurgische Klinik, Universität Erlangen
-
M. Buchfelder
- Neurochirurgische Klinik, Universität Erlangen
-
A. Stadlbauer
- Neurochirurgische Klinik, Universität Erlangen
| Veröffentlicht: | 11. April 2007 |
|---|
Gliederung
Text
Objective: The extent of glioma invasion into the brain parenchyma can not be depicted well in conventional MR imaging. Progress in tumor surgery is highly dependant on improvement in new imaging modalities which enable better visualization of the tumor infiltration zone. In this study we investigated the potential of combined quantitative diffusion tensor (DT) fiber tracking and proton MR spectroscopic imaging (1H-MRSI) to determine changes in the pyramidal tract adjacent to gliomas.
Methods: Quantitative DT fiber tracking and 1H-MRSI were performed in 20 patients with WHO grade II–IV gliomas. Eight patients suffered preoperative sensorimotor deficits. Mean diffusivity (MD), fractional anisotropy (FA), and number-of-fibers/voxel (FpV) were calculated for the pyramidal tract of the ipsilateral and contralateral hemisphere. Metabolite concentrations for choline-containing compounds (Cho) and N-acetyl-aspartate (NAA) were computed for all voxels located at the pyramidal tracts using LCModel.
Results: For the whole pyramidal tract quantitative DT fiber tracking resulted in significantly lower FpV and FA (P<0.001) values for the ipsilateral hemisphere, but not for MD. For the section of the fiber bundle closest to the lesion we found significantly decreased FpV and FA (P<0.001) and increased MD (P=0.002). MRSI showed significantly decreased NAA (P=0.001), increased Cho (P=0.034) and Cho/NAA (P=0.001) for the same volumes of interest in the ipsilateral pyramidal tract. In patients suffering sensorimotor deficits, we found significantly lower FA (P=0.022) and higher MD values (P=0.026) and a strongly negative correlation between FA and MD (R=-0.710, P=0.024), but no correlation in patients without sensorimotor deficits (R=0.078, ns).
Conclusions: Combining quantitative DTI and 1H-MRSI provided important information on changes in white matter structures, which are not detectable by conventional MR imaging. Differences for diffusivity parameters FA and MD in the ipsilateral pyramidal tract are thought to reflect preoperative sensorimotor deficits. These findings may help to differentiate between edema versus tumor infiltration in tumor-associated neurologic deficits.
