Assessment of Blood Flow Transport in the Left Ventricle Using Ultrasound. Validation Against 4-D Flow Cardiac Magnetic Resonance

Four-dimensional flow cardiac magnetic resonance (CMR) is the reference technique for analyzing blood transport in the left ventricle (LV), but similar information can be obtained from ultrasound. We aimed to validate ultrasound-derived transport in a head-to-head comparison against 4D flow CMR. In five patients and two healthy volunteers, we obtained 2D + t and 3D + t (4D) flow fields in the LV using transthoracic echocardiog-raphy and CMR, respectively. We compartmentalized intraventricular blood flow into four fractions of end -dia-stolic volume: direct flow (DF), retained inflow (RI), delayed ejection flow (DEF) and residual volume (RV). Using ultrasound we also computed the properties of LV filling waves (percentage of LV penetration and percent-age of LV volume carried by E/A waves) to determine their relationships with CMR transport. Agreement between both techniques for quantifying transport fractions was good for DF and RV (Ric [95% confidence inter-val]: 0.82 [0.33, 0.97] and 0.85 [0.41, 0.97], respectively) and moderate for RI and DEF (Ric= 0.47 [-0.29, 0.88] and 0.55 [-0.20, 0.90], respectively). Agreement between techniques to measure kinetic energy was variable. The amount of blood carried by the E-wave correlated with DF and RV (R = 0.75 and R = 0.63, respectively). There-fore, ultrasound is a suitable method for expanding the analysis of intraventricular flow transport in the clinical setting. (E-mail: javier.bermejo@salud.madrid.org) (c) 2022 The Author(s). Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology. Funding Agencies|Comunidad de Madrid [Y2018/BIO-4858 PREFI-CM]; Instituto de Salud Carlos III [DTS/1900063, PI15/02211]; Spanish Society of Cardiology (ISBIDCM); Ministerio de Economia y Competitividad, Spain [BES-2017-079924]; Swedish Research Council [2018-04454]; Swedish Heart and Lung Foundation [20210441]; EU-European Regional Development Fund