Impact of Eddy Currents Correction in Aortic Pulse Wave Velocity Assessment on 4D Flow Magnetic Resonance Images
AbstractArterial stiffness is an independent predictor of cardiovascular disease, usually estimated using Pulse Wave Velocity (PWV) measurements. PWV can be calculated estimating the distance between different arterial beds and the time-shift of their respective pressure or flow. Non-invasively, PWV can be calculated by tonometry or with Magnetic Resonance Images (MRI) techniques (2D+t or 3D+t). In 2D+t studies only two measurement sites are possible, whereas in 3D+t, several arbitrary locations can be analyzed. When acquiring velocities in MRI, there is an offset error that needs to be corrected (“zero correction”). The aim of this work was to study the impact of this correction in PWV estimations. We acquired 4D Flow MRI sequences in seven asymptomatic healthy volunteers. We estimated the flow in five sites of the thoracic aorta along with the distance amongst them. The slope of a linear regression model between time-shift and distance allowed the estimation of the PWV. We compared the values before and after the zero correction. Mean and standard deviation of PWV were 11.09 ± 1.80 m/s and 11.88 ± 2.89 m/s, respectively (p=0.23). We concluded that PWV can be assessed in 4D Flow MRI sequences and the zero correction did not modify the PWV values.