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Regional distribution of measurement error in diffusion tensor imaging.
Stefano Marenco1, Robert Rawlings, Gustavo K Rohde
1Genes, Cognition and Psychosis Program, Clinical Brain Disorders Branch, IRP, NIMH, Bethesda, MD 20892, USA. marencos@mail.nih.gov
Psychiatry Research
|June 27, 2006
Summary
Diffusion Tensor Imaging (DTI) measurement error is key for psychiatric studies. Our findings show good reproducibility for Fractional Anisotropy (FA) and Trace (D), crucial for reliable DTI analysis.
Area of Science:
- Neuroimaging
- Medical Physics
- Psychiatric Research
Background:
- Characterizing measurement error in Diffusion Tensor Imaging (DTI) is essential for interpreting findings in psychiatric research.
- Longitudinal and cohort studies of psychiatric disorders rely on accurate and reproducible DTI metrics.
Purpose of the Study:
- To assess the intersession variability and reproducibility of key DTI metrics, Fractional Anisotropy (FA) and Trace (D).
- To evaluate the impact of measurement error on DTI findings in healthy volunteers for future psychiatric studies.
Main Methods:
- Utilized a single-shot echo-planar DTI technique on 20 healthy volunteers, with each participant scanned twice.
- Quantified intersession variability using standard deviation within subjects (SDw), percent coefficient of variation (CV), and intra-class correlation coefficient (ICC).
- Employed repeated measures ANOVA and non-parametric paired t-tests to assess statistical significance of differences between sessions.
Main Results:
- Demonstrated good reproducibility for both FA and Trace, with CVs generally below 10% and ICCs at or above 0.70 in most regions of interest.
- Identified evidence of systematic global changes in Trace between the two scanning sessions.
- Observed that the regional distribution of reproducibility varied across SDw, CV, and ICC metrics.
Conclusions:
- The study confirms good reproducibility of FA and Trace in DTI, supporting its use in longitudinal psychiatric research.
- Findings highlight the importance of considering the regional distribution of reproducibility and complementary information from different variability measures (SDw, CV, ICC).
- Results have implications for the interpretation of regional DTI findings and the development of rigorous pre-processing pipelines for psychiatric studies.