A theoretical framework for determining cerebral vascular function and heterogeneity from dynamic susceptibility...

Area of Science:

• Neuroimaging
• Cerebrovascular Biology
• Biophysics

Background:

• Understanding brain vascular heterogeneity is crucial for diagnosing and treating cerebrovascular diseases.
• Previous work utilized vessel architectural imaging (VAI), but a comprehensive framework for dynamic analysis was lacking.

Purpose of the Study:

• To develop a theoretical framework for assessing cerebral vascular function and heterogeneity using dynamic susceptibility contrast MRI.
• To model realistic vascular architectures and hemodynamic conditions for accurate analysis.

Main Methods:

• Developed a tissue model incorporating realistic vessel branching, orientations, and hemodynamic parameters (blood flow, capillary transit times, oxygenation).
• Utilized dynamic susceptibility contrast MRI data (simulated and patient-derived).
• Analyzed apparent MRI relaxation rates and the vortex area parameter derived from VAI.

Main Results:

• Apparent MRI relaxation rates were found to be independent of mean vessel orientation within image voxels.
• The vortex area parameter correlated with relative oxygen saturation and vessel branching.
• Distinct distributions of the vortex area parameter versus capillary transit times were observed in normal-appearing white/gray matter compared to tumor tissue.

Conclusions:

• The proposed framework enables in vivo, per-voxel determination of vascular status and heterogeneity in cerebral tissue.
• This approach offers a potential roadmap for improved diagnostic capabilities in cerebrovascular diseases and neuro-oncology.