Real-Time Phase-Contrast Flow MRI Aids in Diagnosing Carotid Stenosis

RT-PC MRI yields velocity distributions across the entire vessel lumen.

Real-time phase-contrast (RT-PC) flow MRI adds to clinical diagnostics in patients with carotid stenosis, according to a study published in the European Journal of Radiology.

Researchers from Germany performed a small study with 20 healthy subjects to examine the utility and accuracy of assessing carotid artery flow by neurovascular ultrasound (nvUS), complemented by real-time phase-contrast (RT-PC) flow MRI.

The feasibility and diagnostic potential of RT-PC flow MRI was in comparison to conventional nvUS. RT-PC flow MRI at 40 ms temporal resolution and 0.8 mm in-plane resolution resulted in velocity maps with low phase noise and high spatiotemporal accuracy by exploiting respective advances of a recent nonlinear inverse model-based reconstruction. Peak-systolic velocities (PSV), end-diastolic velocities (EDV), flow volumes and comprehensive velocity profiles were determined in the common, internal and external carotid artery on both sides.

The results showed flow characteristics such as pulsatility and individual abnormalities shown on nvUS could be reproduced and visualized in detail by RT-PC flow MRI. PSV to EDV differences revealed good agreement between both techniques, mean PSV and EDV were significantly lower and flow volumes were higher for MRI.

The researchers concluded that their findings suggested RT-PC flow MRI adds to clinical diagnostics, alterations of dynamic velocity distributions in patients with carotid stenosis, and other means. Lower PSV and EDV values than for nvUS mainly reflect the longer MRI acquisition time which attenuates short peak velocities, while higher flow volumes benefit from a proper assessment of the true vessel lumen.