Related Experiment Video
Updated: Jul 19, 2026
17:06
Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging
Published on: November 8, 2012
Between session reproducibility and between subject variability of diffusion MR and tractography measures
E Heiervang1, T E J Behrens, C E Mackay
1Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK.
Neuroimage
|September 27, 2006
Summary
Diffusion tractography measures like mean fractional anisotropy (FA) and mean diffusivity (MD) show good reproducibility. Tract definition using two regions of interest (ROIs) improves reliability for clinical applications.
Area of Science:
- Neuroimaging
- Biomedical Engineering
- Radiology
Background:
- Diffusion tractography is vital for quantitative clinical measures.
- Assessing reproducibility and variability is crucial for reliable clinical use.
Purpose of the Study:
- To characterize inter-session reproducibility and inter-subject variability of diffusion tractography measures.
- To compare different seed definition methods and diffusion encoding directions.
Main Methods:
- Probabilistic tractography applied to 8 subjects scanned 3 times.
- Defined cingulum bundle, pyramidal tracts, optic radiations, and genu of the corpus callosum.
- Evaluated mean FA, MD, and tract volume using three seed definition methods.
Main Results:
- Mean FA and MD measures were more reproducible than tract volume.
- Two ROI seed definition yielded higher reproducibility than manual seed masks.
- Inter-session CVs for FA and MD were below 5% and 3% respectively with the two ROI method.
- 12 diffusion directions were sufficient for core bundle definition but less sensitive to smaller pathways.
Conclusions:
- Diffusion tractography measures, particularly mean FA and MD, demonstrate good reproducibility and low variability.
- The two ROI seed definition method enhances tractography reliability for clinical studies.
- Reduced diffusion encoding directions (12) can be adequate for large bundle reproducibility, impacting sensitivity to smaller structures.
