Assessment of Intravoxel Incoherent Motion Diffusion-Weighted Imaging in Insomnia.

Area of Science:

• Neuroimaging
• Sleep Medicine
• Diffusion MRI

Background:

• Insomnia disorder is prevalent, yet its underlying pathophysiology remains incompletely understood.
• Intravoxel incoherent motion (IVIM) imaging offers insights into tissue microcirculation and microstructure.
• Few studies have utilized IVIM imaging to investigate insomnia.

Purpose of the Study:

• To assess the diagnostic performance of IVIM diffusion-weighted imaging in distinguishing insomnia disorder patients from healthy controls.
• To explore the interplay between sleep quality, cerebral microcirculation, and glymphatic system function in insomnia.

Main Methods:

• Recruited 42 insomnia patients and 42 healthy controls.
• Acquired MRI data, including measurements of enlarged perivascular spaces (reflecting glymphatic function).
• Calculated IVIM parameters (pure diffusion coefficient, pseudo-diffusion coefficient, perfusion fraction) and performed correlation and mediation analyses.

Main Results:

• Significant differences in perfusion parameters (D* and f) were observed in multiple brain regions between groups.
• An SVM classifier using IVIM parameters achieved high diagnostic accuracy (AUC = 0.92).
• IVIM parameter D* in the thalamus mediated the association between sleep quality and enlarged perivascular spaces.

Conclusions:

• IVIM imaging demonstrates potential as a valuable tool for classifying insomnia disorder.
• Cerebral microcirculation plays a mediating role in the relationship between insomnia and impaired glymphatic system function.