Multi-Point 3D Velocity Vector Encoding of Blood Flow

Magnetic Resonance Imaging offers the possibility to non-invasively assess blood flow. Different diseases in the cardiovascular system are closely linked to pathological flow and information about the flow can be employed to diagnose and investigate such diseases.

There exist well-established methods to measure the mean velocity of blood flow, and recently a technique to assess turbulence intensity was proposed. All these approaches suffer from high sensitivity to chosen scan parameters and noise. In this work a new method is presented which combines highly accelerated measurements with a Bayesian approach. Phase-Contrast Magnetic Resonance Imaging is employed using different encoding velocities. Coherent motion leads to a velocity depending phase, and velocity fluctuations caused by turbulence lead to a decrease in signal magnitude. These effects in combination with statistical methods result in a posterior probability of the mean velocity and turbulence intensity. This probability is then maximized to obtain an estimate of these parameters.

The technique proposed has shown promising results regarding the accuracy compared to conventional methods, especially in the low SNR regime. The practicability was demonstrated using in vitro as well as in vivo measurements, including pathological flow situations. Further investigation is required to improve speed and to validate the results of turbulence intensities.