DTI of the visual pathway - white matter tracts and cerebral lesions
| Autor: | Georges Dooms, Hans Boecher Schwarz, Frank Hertel, Vimal Raj Nitish Gunness, Ardian Hana, Andreas Husch, Anisa Hana, Christophe Berthold |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
medicine.medical_specialty
Computer science Image quality General Chemical Engineering Optic chiasm Visual system computer.software_genre General Biochemistry Genetics and Molecular Biology Neurosurgical Procedures White matter Voxel medicine Humans Visual Pathways Acquisition Time Frame General Immunology and Microbiology business.industry Brain Neoplasms General Neuroscience White Matter Surgery Visual cortex medicine.anatomical_structure Diffusion Tensor Imaging Medicine Neoplasm Recurrence Local Nuclear medicine business Glioblastoma computer Software Tractography |
| Zdroj: | Journal of visualized experiments : JoVE. (90) |
| ISSN: | 1940-087X |
| Popis: | DTI is a technique that identifies white matter tracts (WMT) non-invasively in healthy and non-healthy patients using diffusion measurements. Similar to visual pathways (VP), WMT are not visible with classical MRI or intra-operatively with microscope. DIT will help neurosurgeons to prevent destruction of the VP while removing lesions adjacent to this WMT. We have performed DTI on fifty patients before and after surgery between March 2012 to January 2014. To navigate we used a 3DT1-weighted sequence. Additionally, we performed a T2-weighted and DTI-sequences. The parameters used were, FOV: 200 x 200 mm, slice thickness: 2 mm, and acquisition matrix: 96 x 96 yielding nearly isotropic voxels of 2 x 2 x 2 mm. Axial MRI was carried out using a 32 gradient direction and one b0-image. We used Echo-Planar-Imaging (EPI) and ASSET parallel imaging with an acceleration factor of 2 and b-value of 800 s/mm². The scanning time was less than 9 min. The DTI-data obtained were processed using a FDA approved surgical navigation system program which uses a straightforward fiber-tracking approach known as fiber assignment by continuous tracking (FACT). This is based on the propagation of lines between regions of interest (ROI) which is defined by a physician. A maximum angle of 50, FA start value of 0.10 and ADC stop value of 0.20 mm²/s were the parameters used for tractography. There are some limitations to this technique. The limited acquisition time frame enforces trade-offs in the image quality. Another important point not to be neglected is the brain shift during surgery. As for the latter intra-operative MRI might be helpful. Furthermore the risk of false positive or false negative tracts needs to be taken into account which might compromise the final results. |
| Databáze: | OpenAIRE |
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