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Updated: Jun 23, 2026
Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging
Published on: November 8, 2012
Reproducibility of Diffusion MRI-Based Tractography in the Fetal Brain
Jiaxin Xiao1, Cong Sun2, Ruike Chen1
1Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.
Background:
Tractography based on diffusion MRI (dMRI) is a useful tool to study white matter of the developing brain. However, its application in fetal brains is limited due to motion artifacts and low resolution of in utero dMRI, leading to reduced reliability, which was scarcely investigated in previous studies.
Purpose:
To identify reliably traceable fibers in fetal brains and assess whether reproducibility varies with gestational age (GA) and varies between brain regions.
Study Type:
Prospective cohort study.
Subjects:
A total of 44 healthy fetuses with GAs between 25 and 37 (31 ± 6).
Field Strength/Sequence:
3-T, diffusion-weighted echo-planar imaging sequence (2-5 repeated dMRI scans within the same session per subject).
Assessment:
We fitted dMRI with constrained spherical deconvolution model and conducted tractography on eight fibers. We extracted volume, fractional anisotropy, and fiber count for each fiber and assessed the reproducibility of these metrics between repeated scans within each subject. Data were divided into two age-based subgroups (≤30 weeks, N = 28, and >30 weeks, N = 16) for further tests.
Statistical Tests:
The reproducibility were compared between fibers by analysis of variance and two-sample t tests. Multiple comparisons were corrected by the false discovery rate (5% was accepted).
Results:
The reproducibility of the anterior thalamic radiation, inferior longitudinal fasciculus (ILF), genu of the corpus callosum (GCC), and body of the corpus callosum (BCC) significantly decreased with advancing GA (correlation coefficient = 0.525-0.823), as confirmed by group comparisons between fetuses in early GA (≤30 weeks) and late GA (>30 weeks) groups. Corticospinal tract, inferior fronto-occipital fasciculus, and GCC showed high reproducibility for fiber count (weighted dice average = 0.846 vs. 0.814), while BCC and ILF exhibited the lowest reproducibility in both age groups.
Data Conclusion:
The study indicates that the reliability of fetal brain tractography depends on GA and varies among different fibers.
Level Of Evidence:
2 TECHNICAL EFFICACY: Stage 2.
Insights
The reliability of fetal brain tractography decreases with advancing gestational age, with significant variations observed across different white matter tracts. Fiber count reproducibility is generally high, but some tracts like the body of the corpus callosum show lower reliability.
Area of Science:
- Neuroimaging
- Developmental Neuroscience
- Medical Imaging Analysis
Background:
- Diffusion MRI (dMRI) tractography is crucial for studying developing white matter.
- In utero dMRI faces limitations like motion artifacts and low resolution, impacting fetal brain tractography reliability.
- Previous studies have scarcely investigated the reliability of fetal brain tractography.
Purpose of the Study:
- To identify reliably traceable white matter fibers in fetal brains.
- To assess how tract reproducibility varies with gestational age (GA).
- To determine if tract reproducibility differs between various brain regions.
Main Methods:
- Prospective cohort study of 44 healthy fetuses (GA 25-37 weeks).
- Utilized 3-T dMRI with repeated scans and constrained spherical deconvolution modeling.
- Analyzed tractography reproducibility for eight major white matter fibers, comparing early (≤30 weeks) and late (>30 weeks) GA groups.
Main Results:
- Reproducibility of anterior thalamic radiation, inferior longitudinal fasciculus (ILF), genu of the corpus callosum (GCC), and body of the corpus callosum (BCC) significantly decreased with advancing GA.
- Corticospinal tract, inferior fronto-occipital fasciculus, and GCC showed high fiber count reproducibility (average Dice > 0.81).
- BCC and ILF exhibited the lowest reproducibility in both early and late GA groups.
Conclusions:
- Fetal brain tractography reliability is dependent on gestational age.
- The reproducibility of white matter tract identification varies significantly between different brain regions.
- These findings highlight the need to consider GA and specific fiber characteristics when interpreting fetal dMRI tractography.
