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Exploring the link between intravoxel incoherent motion measured brain diffusivity during wakefulness and sleep
Lena Meinhold1, Misha P T Kaandorp1, Ziyao Shang2
1Center for MR Research, University Children's Hospital, Zurich, Switzerland; University of Zurich, Zurich, Switzerland.
Neuroimage
|July 2, 2026
Summary
Better sleep quality and increased physical activity in healthy older adults were associated with lower Intravoxel Incoherent Motion (IVIM) fD* values. These findings suggest a link between microvascular function, sleep, and activity levels.
Area of Science:
- Neuroimaging
- Gerontology
- Sleep Science
Background:
- Intravoxel Incoherent Motion (IVIM) is a diffusion-weighted MRI technique measuring tissue diffusivity (D) and microvascular perfusion (D*, f).
- Understanding the relationship between brain microcirculation, sleep, and physical activity in aging is crucial for cognitive health.
Purpose of the Study:
- To investigate the association between IVIM parameters and sleep macrostructure in healthy elderly individuals.
- To explore the correlation between IVIM metrics and physical activity levels in the same cohort.
Main Methods:
- Observational study involving 19 healthy elderly participants (mean age 72.2±5.0).
- Two MRI sessions using a GE 3T Premier scanner to acquire IVIM data.
- Sleep macrostructure assessed via portable EEG (10-14 nights); physical activity monitored with actigraphy.
- IVIM parameters (D, D*, f, fD*) calculated using non-linear least-squares and a deep learning transformer-based estimator.
Main Results:
- Higher physical activity and better EEG-derived sleep quality were predominantly associated with lower estimated IVIM fD* values.
- These associations were observed across seven regions of interest.
- Sensitivity analyses including physical activity supported the primary findings.
Conclusions:
- Lower IVIM fD* values in healthy older adults may be linked to improved sleep quality and higher physical activity.
- Findings suggest potential alterations in microvascular perfusion or cerebrospinal fluid dynamics related to sleep and activity.
- Further research is warranted to elucidate the mechanisms connecting IVIM metrics, sleep quality, and brain health.
