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Updated: Sep 14, 2025
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Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging
Published on: November 8, 2012
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Contribution of white matter microstructure to diffusion tensor image analysis along perivascular space in
Toshiaki Taoka1,2, Kunihiro Iwamoto3, Seiko Miyata3
1Department of Innovative Biomedical Visualization (iBMV), Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan. taoka.toshiaki.v1@f.mail.nagoya-u.ac.jp.
Japanese Journal of Radiology
|July 24, 2025
Summary
The ALPS index, used to assess perivascular spaces, is affected by white matter fibers in patients with obstructive sleep apnea (OSA). This suggests white matter influences interstitial fluid flow, impacting brain health.
Area of Science:
- Neuroimaging
- Sleep Medicine
- White Matter Neuroscience
Background:
- Obstructive sleep apnea (OSA) is linked to neurological complications.
- Diffusion tensor imaging (DTI) analyzes white matter microstructure.
- Perivascular spaces (PVS) are crucial for brain waste clearance.
Purpose of the Study:
- To determine if the DTI-ALPS index is influenced by white matter fibers in OSA patients.
- To investigate associations between DTI-ALPS, sleep data, and neurofluid metrics.
- To explore the role of white matter diffusivity in PVS function.
Main Methods:
- Brain MRI (DTI, structural) and polysomnography in 50 OSA patients.
- Calculation of original and variant ALPS indices.
- Correlation and mediation analyses with sleep variables, choroid plexus volume (CPV), and white matter hyperintensity volume (WMHV).
Main Results:
- ALPS index showed correlations with sleep variables, CPV, and WMHV.
- Mediation analysis confirmed white matter diffusivity influences the ALPS index.
- Variant ALPS indices in the corpus callosum may reflect PVS fluid motion.
Conclusions:
- The ALPS index is influenced by PVS diffusivity and white matter microstructure, especially commissural fibers.
- ALPS is not a highly specific marker for PVS function, but variant indices show partial PVS contribution.
- Associations with sleep and neurofluid metrics suggest white matter pathways facilitate interstitial fluid flow.
