TRACC-PHYSIO: Time-domain Resolution-Aligned Cross-Correlation to estimate PHYSIOlogical coupling and time delays in...

Area of Science:

• Neuroimaging
• Physiological monitoring
• Medical physics

Background:

• Physiological brain pulsations are crucial for neurofluid circulation and waste clearance.
• Standard MRI techniques often lack the temporal resolution to capture these dynamics.
• This limits the understanding of brain pulsation-related physiological information.

Purpose of the Study:

• Introduce TRACC-PHYSIO, a novel time-domain framework for analyzing physiological coupling in dynamic MRI.
• Validate TRACC-PHYSIO's ability to quantify cardiac and respiratory pulse time delays and coupling strengths.
• Assess performance across various simulation conditions, including different physiological compositions and MRI acquisition parameters.

Main Methods:

• Developed TRACC-PHYSIO, a cross-correlation based analytical framework.
• Simulated realistic dynamic MR signals with mixed cardiac and respiratory physiological components.
• Evaluated performance using metrics like peak Coupling Coefficient (peak CorrCoeff) and TimeDelay under varying TRs and acquisition times.

Main Results:

• TRACC-PHYSIO robustly quantifies coupling strengths and time delays for both cardiac (TRACC-Cardiac) and respiratory (TRACC-Respiratory) pulsations.
• The method demonstrates reliable performance even with long repetition times (TRs) up to 3 seconds.
• Systematic simulations confirmed the framework's accuracy across diverse physiological and acquisition scenarios.

Conclusions:

• TRACC-PHYSIO enables reliable time-domain analysis of physiological coupling in dynamic MRI without fast acquisition.
• The framework provides millisecond-level temporal resolution for pulse time delays, revealing hidden physiological information.
• TRACC-PHYSIO offers new possibilities for studying brain pulsation mechanisms and neurofluid dynamics in health and disease.