A groundbreaking study from Mayo Clinic researchers, published in BME Frontiers, introduces Radon transform-based flow measurement (R-Flow)—a contrast-free ultrasound method that redefines microvascular imaging. This innovation addresses critical limitations in traditional techniques, offering real-time, angle-independent visualization of blood flow dynamics at the microvascular scale, with transformative implications for diseases like liver cirrhosis.
R-Flow leverages the Radon transform to decode red blood cell trajectories from ultrasound signals, reconstructing both axial and lateral velocity vectors. Unlike conventional Doppler ultrasound, which struggles with multidirectional flow and requires contrast agents, R-Flow captures complete 2D flow patterns without angle dependency. Simulations confirm its accuracy across flow speeds (1-60 mm/s) and angles, while phantom experiments show strong correlations (r > 0.8) with reference measurements.
In vivo studies validate R-Flow's clinical potential. In a chick embryo model, it mapped lateral blood flow components often missed by traditional methods. Human liver imaging revealed high-sensitivity flow vector maps, demonstrating >0.9 correlation with reference techniques. Crucially, a rat cirrhosis model showed R-Flow's ability to detect pathological flow redistribution—from healthy multipath perfusion to directionally biased patterns—correlating with fibrosis stage and hypoxia levels.
As a contrast-free, real-time solution, R-Flow promises to transform clinical practice and research, enabling precise evaluation of microvascular health in diseases like cirrhosis—ushering in a new era of precision diagnostics.
