Increased precision in the intravascular arterial input function with flow compensation

Abstract

Abstract: Purpose: In this study, we investigate the effects of pulsatile flow and inflow on dynamic susceptibility-contrast MRI (DSC-MRI) intravascular arterial input function (AIF) measurement in human brain arteries and measure how they are affected by first-order flow compensation (FC). Methods: A dual-echo single-shot EPI sequence with alternating FC gradients was used to acquire DSC-MRI data with electrocardiogram monitoring. The dynamic signal variations measured inside the middle- (MCA) and internal cerebral arteries (ICA) was associated to the pulsatile arterial blood velocities measured with a single-slice quantitative flow sequence throughout the cardiac cycle. Results: Major inverse correlations between intravascular signal and blood velocity were found for the standard SS-EPI sequence. FC reduces these correlated variations that contribute to signal physiological noise. It causes a significant two-fold increase of intravascular SNR in the MCA and the ICA, (2.3 ± 0.9, P = 0.03) and (2.0 ± 0.9, P = 0.04) respectively; and reduced phase standard deviation for the ICA (0.72 ± 0.14, P = 0.004). The correction proposed in this work translates into a quantitative AIF with reduced noise in the ICA. Conclusion: The physiological noise added by pulsatile flow and inflow for intravascular AIF measurement in the brain arteries is significantly reduced by FC.