In vivo velocity and flow errors quantification by phase-contrast magnetic resonance imaging

Magnetic resonance imaging is a very efficient tool for assessing velocity and flow in the cardiovascular system under normal and pathological conditions. However, this technique still has some limitations that produce different type of errors. In this study, velocities and flow were measured in vivo using phase-contrast method to determine the optimal number of phases allowing the minimization of the errors. The effect of velocity encoding upsampling was also investigated. The results showed that a number of phases between 16-24 is a good compromise to accurately estimate both ejection and regurgitant flows. Furthermore, a time shift effect caused by velocity encoding upsampling was found and a corrective linear model was proposed. These considerations may reduce flow and velocity measurement errors in normal and pathological conditions.