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Updated: Jul 8, 2025
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Automatic estimation of brain parenchymal fraction in patients with multple sclerosis: a comparison between synthetic
Ilyas Yazici1, Britta Krieger1, Barbara Bellenberg1
1Institute of Neuroradiology, St. Josef Hospital, Ruhr-University Bochum, Gudrunstrasse 56, 44791, Bochum, Germany.
Purpose:
We aimed to validate the estimation of the brain parenchymal fraction (BPF) in patients with multiple sclerosis (MS) using synthetic magnetic resonance imaging (SyMRI) by comparison with software tools of the FMRIB Software Library (FSL). In addition to a cross-sectional method comparison, longitudinal volume changes were assessed to further elucidate the suitability of SyMRI for quantification of disease-specific changes.
Methods:
MRI data from 216 patients with MS and 28 control participants were included for volume estimation by SyMRI and FSL-SIENAX. Moreover, longitudinal data from 35 patients with MS were used to compare registration-based percentage brain volume changes estimated using FSL-SIENA to difference-based calculations of volume changes using SyMRI.
Results:
We observed strong correlations of estimated brain volumes between the two methods. While SyMRI overestimated grey matter and BPF compared to FSL-SIENAX, indicating a systematic bias, there was excellent agreement according to intra-class correlation coefficients for grey matter and good agreement for BPF and white matter. Bland-Altman plots suggested that the inter-method differences in BPF were smaller in patients with brain atrophy compared to those without atrophy. Longitudinal analyses revealed a tendency for higher atrophy rates for SyMRI than for SIENA, but SyMRI had a robust correlation and a good agreement with SIENA.
Conclusion:
In summary, BPF based on data from SyMRI and FSL-SIENAX is not directly transferable because an overestimation and higher variability of SyMRI values were observed. However, the consistency and correlations between the two methods were satisfactory, and SyMRI was suitable to quantify disease-specific atrophy in MS.
Insights
Synthetic MRI (SyMRI) shows good agreement for brain parenchymal fraction (BPF) in multiple sclerosis (MS) patients, despite some overestimation compared to FSL software. SyMRI is suitable for quantifying MS-related brain atrophy.
Area of Science:
- Neuroimaging
- Radiology
- Biomedical Engineering
Background:
- Multiple Sclerosis (MS) is a chronic neurological disease characterized by progressive brain atrophy.
- Accurate quantification of brain volume changes is crucial for monitoring MS progression and treatment efficacy.
- Synthetic Magnetic Resonance Imaging (SyMRI) offers potential for rapid and quantitative tissue characterization.
Purpose of the Study:
- To validate brain parenchymal fraction (BPF) estimation using SyMRI against established FMRIB Software Library (FSL) tools in MS patients.
- To compare cross-sectional and longitudinal brain volume changes derived from SyMRI and FSL.
- To assess SyMRI's suitability for quantifying disease-specific atrophy in MS.
Main Methods:
- Cross-sectional comparison of BPF and grey/white matter volumes between SyMRI and FSL-SIENAX in 216 MS patients and 28 controls.
- Longitudinal analysis of brain volume changes using SyMRI and FSL-SIENA in 35 MS patients.
- Statistical analysis including correlation, intra-class correlation coefficients, and Bland-Altman plots.
Main Results:
- Strong correlations observed between SyMRI and FSL for estimated brain volumes.
- SyMRI showed a systematic bias, overestimating grey matter and BPF compared to FSL-SIENAX.
- Excellent agreement for grey matter and good agreement for BPF and white matter volumes were found.
- Longitudinal analyses indicated higher atrophy rates with SyMRI but demonstrated robust correlation and good agreement with FSL-SIENA.
Conclusions:
- BPF derived from SyMRI and FSL-SIENAX are not directly interchangeable due to SyMRI's overestimation and variability.
- Despite systematic bias, SyMRI demonstrates satisfactory consistency and correlation with FSL.
- SyMRI is a suitable tool for quantifying disease-specific brain atrophy in multiple sclerosis.
