A multiphysics model to predict periventricular white matter hyperintensity growth during healthy brain aging

Area of Science:

• Neuroimaging
• Computational Biology
• Biophysics

Background:

• Periventricular white matter hyperintensities (WMH) are common in aging brains, linked to small vessel disease and inflammation.
• The exact cause of periventricular WMH remains unclear, despite extensive research.
• A potential link exists between age-related ventricular expansion and ventricular wall degeneration, affecting the brain-fluid barrier.

Purpose of the Study:

• To develop and validate a multiphysics model simulating periventricular WMH formation and progression.
• To investigate the coupling between cerebral atrophy-driven ventricular wall loading and WMH development.
• To analyze the spatiotemporal characteristics and influencing factors of WMH growth.

Main Methods:

• Creation of eight 2D finite element models using patient data.
• Coupling of cerebral atrophy-induced ventricular wall loading with WMH progression.
• Simulation and analysis of WMH growth patterns and onset timing.

Main Results:

• The model accurately captures the spatiotemporal features of periventricular WMH growth.
• WMH damage initiates in the anterior and posterior horns, spreading to deeper white matter.
• WMH onset can be delayed up to 12 years, with an average annualized growth rate of 15.2 ± 12.7 mm²/year.
• The septum pellucidum initially delays WMH onset but increases the long-term WMH load.

Conclusions:

• The developed multiphysics model provides a framework for understanding periventricular WMH etiology.
• Age-related ventricular expansion and ventricular wall degeneration are key factors in WMH formation.
• The model's sensitivity analysis supports its ability to explain individual differences in WMH onset and progression.