Carotid Phase-Contrast Magnetic Resonance before Treatment: 4D-Flow versus Standard 2D Imaging

Secchi F, Monti CB, Capra D, Vitale R, Mazzaccaro D, Conti M, Jin N, Giese D, Nano G, Sardanelli F, Marrocco-Trischitta MM. Carotid Phase-Contrast Magnetic Resonance before Treatment: 4D-Flow versus Standard 2D Imaging. Tomography. 2021 Sep 28;7(4):513-522. doi: 10.3390/tomography7040044. PMID: 34698250; PMCID: PMC8544659. Abstract The purpose of this study was to evaluate the level of agreement between flow/velocity data obtained from 2D-phase-contrast (PC) and 4D-flow in patients scheduled for treatment of carotid artery stenosis. Image acquisition was performed using a 1.5 T scanner. We compared mean flow rates, vessel areas, and peak velocities obtained during the acquisition with both techniques in 20 consecutive patients, 15 males and 5 females aged 69 ± 5 years (mean ± standard deviation). There was a good correlation between both techniques for the CCA flow (<em>r</em> = 0.65, <em>p</em> &lt; 0.001), whereas for the ICA flow and ECA flow the correlation was only moderate (<em>r</em> = 0.4, <em>p</em> = 0.011 and <em>r</em> = 0.45, <em>p</em> = 0.003, respectively). Correlations of peak velocities between methods were good for CCA (<em>r</em> = 0.56, <em>p</em> &lt; 0.001) and moderate for ECA (<em>r</em> = 0.41, <em>p</em> = 0.008). There was no correlation for ICA (<em>r</em> = 0.04, <em>p</em> = 0.805). Cross-sectional area values between methods showed no significant correlations for CCA (<em>r</em> = 0.18, <em>p</em> = 0.269), ICA (<em>r</em> = 0.1, <em>p</em> = 0.543), and ECA (<em>r</em> = 0.05, <em>p</em> = 0.767). Conclusion: the 4D-flow imaging provided a good correlation of CCA and a moderate correlation of ICA flow rates against 2D-PC, underestimating peak velocities and overestimating cross-sectional areas in all carotid segments.