Flow 2.0: A Standardized Toolbox for Real-Time Phase-Contrast MRI of Neurofluid Dynamics

Real-time phase-contrast MRI (RT-PC) enables continuous quantification of physiological flow dynamics across multiple temporal frequencies, but its broader application is limited by complex and fragmented post-processing workflows. We developed Flow 2.0, a standardized toolbox for RT-PC designed to integrate segmentation, flow quantification, visualization, and multi-frequency signal analysis within a unified environment.

Flow 2.0 integrates automated ROI segmentation, background phase correction, velocity aliasing correction, interactive waveform visualization, cardiac cycle reconstruction, and Hermitian-preserving frequency-domain processing. A phase-resolved respiratory modulation module enables systematic evaluation of respiratory influences through temporal phase shifting and cycle-based multi-parameter analysis. The framework was demonstrated using representative RT-PC datasets acquired under free and sustained deep breathing conditions.

Automated processing of 500-frame RT-PC datasets was completed within seconds while preserving signal phase integrity. Cardiac cycle reconstruction and respiratory phase classification were consistently applied across acquisition conditions. The phase-resolved analysis module enabled visualization and quantification of respiratory modulation across multiple flow-derived parameters, including mean flow, stroke volume, and cardiac-related metrics.

Flow 2.0 provides a standardized and extensible toolbox for RT-PC MRI, enabling reproducible, phase-resolved, and multi-parametric analysis of neurofluid dynamics within a unified processing environment.