Common Carotid Artery Volume Flow: A Comparison Study between Ultrasound Vector Flow Imaging and Phase Contrast Magnetic Resonance Imaging.

Andreas Hjelm Brandt,Jacob Bjerring Olesen,Michael Bachmann Nielsen,Ramin Moshavegh,Jørgen Arendt Jensen,Kristoffer Lindskov Hansen

doi:10.3390/neurolint13030028

Abstract

Volume flow estimation in the common carotid artery (CCA) can assess the absolute hemodynamic effect of a carotid stenosis. The aim of this study was to compare a commercial vector flow imaging (VFI) setup against the reference method magnetic resonance phase contrast angiography (MRA) for volume flow estimation in the CCA. Ten healthy volunteers were scanned with VFI and MRA over the CCA. VFI had an improved precision of 19.2% compared to MRA of 31.9% (p = 0.061). VFI estimated significantly lower volume flow than MRA (mean difference: 63.2 mL/min, p = 0.017), whilst the correlation between VFI and MRA was strong (R2 = 0.81, p < 0.0001). A Bland–Altman plot indicated a systematic bias. After bias correction, the percentage error was reduced from 41.0% to 25.2%. This study indicated that a VFI setup for volume flow estimation is precise and strongly correlated to MRA volume flow estimation, and after correcting for the systematic bias, VFI and MRA become interchangeable.

Highlights

85% of all strokes are caused by ischemia, while 15% are initiated by hemodynamically significant stenosis of the carotid artery [1,2]
Phase contrast magnetic resonance imaging angiografi (MRA) is considered the gold standard for non-invasive cerebral blood flow measurement; the estimation of common carotid artery (CCA) volume flow with MRA is time consuming, the technique is nonmobile, and the evaluation is not performed in real-time [7]
The vector flow imaging (VFI) volume flow was significantly different to the MRA volume flow when comparing the first of the two replicated measurements (p = 0.017)

Summary

Introduction

85% of all strokes are caused by ischemia, while 15% are initiated by hemodynamically significant stenosis of the carotid artery [1,2]. Volume flow quantification of the common carotid artery (CCA) can assess the absolute hemodynamic effect of a carotid stenosis and can be used for monitoring cerebral blood flow after carotid endarterectomy or carotid stenting stenosis [3,4,5]. Phase contrast magnetic resonance imaging angiografi (MRA) and Doppler ultrasound (US) are commonly used for measuring cerebral blood flow [6]. Phase contrast MRA is considered the gold standard for non-invasive cerebral blood flow measurement; the estimation of CCA volume flow with MRA is time consuming, the technique is nonmobile, and the evaluation is not performed in real-time [7]. While color Doppler is a qualitative method for stenosis assessment in the CCA, spectral Doppler US can provide the CCA volume flow by measuring the mean velocity multiplied with the lumen area found with B-mode imaging.

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