Contribution of white matter microstructure to diffusion tensor image analysis along perivascular space in obstructive sleep apnea.

Authors

Toshiaki Taoka, Kunihiro Iwamoto, Seiko Miyata, Rintaro Ito, Koji Kamagata, Rei Nakamichi, Toshiki Nakane, Mami Iima, Hiroshige Fujishiro, Masashi Ikeda, Kazushige Ichikawa, Akifumi Kamiunten, Nobuyasu Ichinose, Junko Kikuta, Shigeki Aoki, Shinji Naganawa

Published in

Japanese journal of radiology. Jul 24, 2025. Epub Jul 24, 2025.

Abstract

We aimed to evaluate whether the ALPS index derived from diffusion tensor image analysis along the perivascular space (DTI-ALPS) is influenced by white matter fibres within the analysis region, particularly commissural fibres from the corpus callosum that traverse this area in psychiatric patients with suspected obstructive sleep apnea (OSA). We also investigated associations between diffusion-based parameters, sleep-related data, and neurofluid-related imaging metrics.
Fifty participants with OSA underwent brain magnetic resonance imaging and polysomnography, including diffusion tensor and structural sequences. Among them, 8 participants had no psychiatric comorbidities, while the remaining 42 had various psychiatric disorders in addition to OSA. Diffusion-based parameters were obtained, and both the original and variant ALPS index were calculated. Correlation analyses were conducted with sleep-related data and neurofluid-related imaging parameters, including choroid plexus volume (CPV) and volume of white matter lesion burden (WMHV). Mediation analyses were also performed to explore the influence of white matter diffusivity on the perivascular diffusivity index.
The ALPS index showed weak to moderate correlations with multiple sleep-related variables. It also correlated with CPV and WMHV. Mediation analyses demonstrated that diffusivity within white matter fibres was associated with the ALPS index. Moreover, variant ALPS indices measured in the corpus callosum may reflect fluid motion in the direction of perivascular spaces.
These findings suggest that the ALPS index is influenced by both diffusivity along perivascular spaces and white matter microstructure, particularly commissural fibres. Although it should not be regarded as a highly specific marker of perivascular space function, variant indices support partial perivascular contribution. Furthermore, associations with sleep and neurofluid-related metrics imply that white matter architecture and inter-fibre spaces may serve as plausible routes for interstitial fluid flow.

PMID:
40705166
Bibliographic data and abstract were imported from PubMed on 24 Jul 2025.

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