Estimating Pressure Loss Across Stenotic Lesions with Color Doppler.

A reliable assessment of the hemodynamic significance of arterial stenoses requires measurement of the trans-stenotic pressure loss, but existing noninvasive approaches provide only geometric surrogates. We introduce a Doppler-based fluid-dynamics method that uses standard color Doppler imaging to estimate pressure loss across mild to moderate stenoses. First, we developed a two-dimensional vascular vector flow mapping (2D-vVFM) technique. By formulating a physics-constrained optimization problem that enforces incompressibility and free-slip wall boundary conditions, we reconstruct the full 2D velocity vector field from the color Doppler velocities. Next, we estimate the total pressure loss by combining the Bernoulli equation upstream of the vena contracta with a finite-difference solution of the Navier-Stokes equation downstream, thereby capturing both potential to kinetic energy conversion and energy dissipation. In silico validation on axisymmetric carotid stenosis models (60%-70% diameter reduction) at flow rates of 0.3-1 L/min yielded normalized RMSEs below 6.1% (vx) and 1.5% (vz). In vitro experiments on flow phantoms across 44 conditions (0.2-1.2 L/min) with catheter-based pressure measurements up to 30 mmHg further confirmed the accuracy of our approach. Across all in silico and in vitro data, the estimated pressure losses showed excellent agreement with reference values, yielding a combined correlation of r2 = 0:97. This noninvasive, Doppler-only approach enables rapid and quantitative measurement of pressure loss across stenotic lesions, with strong potential to support diagnosis and treatment planning in patients with moderate arterial stenoses.