4D Flow MRI Quantification of Congenital Shunts: Comparison to Invasive Catheterization.

Abstract

Purpose\nTo compare invasive right heart catheterization with four-dimensional (4D) flow MRI for estimating shunt fraction in patients with intracardiac and extracardiac shunts.\n\n\nMaterials and Methods\nIn this retrospective study, patients who underwent 4D flow MRI and invasive right heart catheterization with a shunt run between August 2015 and November 2018 were included. The primary objective was comparison of estimated shunt fraction (ratio of pulmonary-to-systemic flow, Qp/Qs) at 4D flow and catheterization. Secondary objectives included comparison of the right ventricular-to-left ventricular stroke volume ratio (RVSV/LVSV) to shunt fraction (for those with applicable shunts) and comparison of cardiac output between 4D flow and catheterization. Statistical analysis included Pearson correlation and Bland-Altman plots.\n\n\nResults\nA total of 33 patients met inclusion criteria (mean age, 49 years ± 16 [standard deviation]; 24 women). 4D flow measurements of Qp/Qs strongly correlated with those at catheterization (r = 0.938), and there was no bias. RVSV/LVSV correlated strongly with Qp/Qs from 4D flow (r = 0.852) and catheterization (r = 0.842). Measurements of left ventricle (Qs) and right ventricle (QP) cardiac output from 4D flow and catheterization (Fick) correlated moderately overall (r = 0.673 [Qp] and r = 0.750 [Qs]).\n\n\nConclusion\nShunt fraction measurement using 4D flow MRI compares well with that using invasive cardiac catheterization.Supplemental material is available for this article.© RSNA, 2021.