MRI-based comprehensive analysis of vascular anatomy and hemodynamics

Background: Standardized methods for mapping the complex blood flow in vessels are essential for processing the large data volume acquired from 4D Flow MRI. We present a method for systematic and efficient analysis of anatomy and flow in large human blood vessels. To attain the best outcomes in cardiac surgery, vascular modifications that lead to secondary flow patterns such as vortices should be avoided. In this work, attention was paid to the undesired cancelation of vortices with opposite directions of rotation, known as Dean flow patterns, using hemodynamic parameters such as circulation and helicity density. Methods: Our approach is based on the multiplanar reconstruction (MPR) of a multi-dimensional feature-space along the blood vessel's centerline. Hemodynamic parameters and anatomic information were determined in-plane from the reconstructed feature-space and from the blood vessel's centerline. A modified calculation of circulation and helicity density and novel parameters for quantifying Dean flow were developed. To test the model performance, we applied our methods to three test cases. Results: Comprehensive information on position, magnitude and interrelation of vascular anatomy and hemodynamics were extracted from 4D Flow MRI datasets. The results show that the Dean flow patterns can be efficiently assessed using the novel parameters. Conclusions: Our approach to comprehensively and simultaneously quantify multiple parameters of vascular anatomy and hemodynamics from 4D Flow MRI provides new insights to map complex hemodynamic conditions.