Table 8.
Purpose of tractography | Population | Method of evaluation | Result | Metric |
---|---|---|---|---|
Create ROI for evaluating diffusion parameters | HC | Compare fiber number L/R or crossing/non-crossing, per subject | Quantitative | Absolute deviation of proportion from 50% |
Create ROI for evaluating diffusion parameters | HC/patients | Compare with simple atlas-based ROIs | Quantitative | t test of parameter; null finding indicates tract and atlas-based ROIs equivalent |
Create ROI to identify AOP on EPI images | HC/patients | Voxelwise comparison with manually drawn ROIs on EPI images | Quantitative | Value of coefficient (e.g. Dice, NOS) |
Create ROI to identify AOP on non-EPI images | HC/patients | Voxelwise comparison with manually drawn ROIs on non-EPI images | Quantitative | Value of coefficient (e.g. Dice, NOS) |
Evaluate AOP integrity | HC/patients | Include patients with known compromised integrity in test sample | Quantitative or categorical | Normalized fiber number; success/failure of whole AOP reconstruction |
Evaluate AOP displacement | Patients with space-filling lesions | Investigation during surgery | Categorical | Position of AOP relative to lesion, direction of displacement |
Abbreviations: AOP - anterior optic pathway; EPI - eco planar imaging; ROI – region of interest.