Milan Prsa1, Liqun Sun1, Joshua van Amerom1, Shi-Joon Yoo1, Lars Grosse-Wortmann1, Edgar Jaeggi1, Christopher Macgowan1, Mike Seed2. 1. From the Division of Pediatric Cardiology, Department of Pediatrics (M.P., L.S., L.G.-W., E.J., M.S.), Department of Diagnostic Imaging (J.v.A., S.-J.Y., M.S.), and Department of Physiology and Experimental Medicine (C.M.), University of Toronto and Hospital for Sick Children, Toronto, Canada. 2. From the Division of Pediatric Cardiology, Department of Pediatrics (M.P., L.S., L.G.-W., E.J., M.S.), Department of Diagnostic Imaging (J.v.A., S.-J.Y., M.S.), and Department of Physiology and Experimental Medicine (C.M.), University of Toronto and Hospital for Sick Children, Toronto, Canada. mike.seed@sickkids.ca.
Abstract
BACKGROUND: Phase-contrast MRI with metric-optimized gating is a promising new technique for studying the distribution of the fetal circulation. However, mean and reference ranges for blood flow measurements made in the major fetal vessels using this technique are yet to be established. METHODS AND RESULTS: We measured flow in the major vessels of the fetal circulation in 40 late-gestation normal human fetuses using phase-contrast MRI (mean gestational age, 37 [SD=1.1] weeks). Flows were indexed to the fetal weight, which was estimated from the fetal volume calculated by MRI segmentation. The following mean flows (in mL/min per kilogram; ±2SD) were obtained: combined ventricular output, 465 (351, 579); main pulmonary artery, 261 (169, 353); ascending aorta, 191 (121, 261); superior vena cava, 137 (77, 197); ductus arteriosus, 187 (109, 265); descending aorta, 252 (160, 344); pulmonary blood flow, 77 (0, 160); umbilical vein, 134 (62, 206); and foramen ovale, 135 (37, 233). Expressed as percentages of the combined ventricular output, the mean flows±2 SD were as follows: main pulmonary artery, 56 (44, 68); ascending aorta, 41 (29, 53); superior vena cava, 29 (15, 43); ductus arteriosus, 41 (25, 57); descending aorta, 55 (35, 75); pulmonary blood flow, 16 (0, 34); umbilical vein, 29 (11, 47); and foramen ovale, 29 (7, 51). A strong inverse relationship between foramen ovale shunt and pulmonary blood flow was noted (r=-0.64; P<0.0001). CONCLUSIONS: Although too small a sample size to provide normal ranges, these results are in keeping with those predicted in humans based on measurements made in fetal lambs using radioactive microspheres and provide preliminary reference ranges for the late-gestation human fetuses. The wide range we found in foramen ovale shunting suggests a degree of variability in the way blood is streamed through the fetal circulation.
BACKGROUND: Phase-contrast MRI with metric-optimized gating is a promising new technique for studying the distribution of the fetal circulation. However, mean and reference ranges for blood flow measurements made in the major fetal vessels using this technique are yet to be established. METHODS AND RESULTS: We measured flow in the major vessels of the fetal circulation in 40 late-gestation normal human fetuses using phase-contrast MRI (mean gestational age, 37 [SD=1.1] weeks). Flows were indexed to the fetal weight, which was estimated from the fetal volume calculated by MRI segmentation. The following mean flows (in mL/min per kilogram; ±2SD) were obtained: combined ventricular output, 465 (351, 579); main pulmonary artery, 261 (169, 353); ascending aorta, 191 (121, 261); superior vena cava, 137 (77, 197); ductus arteriosus, 187 (109, 265); descending aorta, 252 (160, 344); pulmonary blood flow, 77 (0, 160); umbilical vein, 134 (62, 206); and foramen ovale, 135 (37, 233). Expressed as percentages of the combined ventricular output, the mean flows±2 SD were as follows: main pulmonary artery, 56 (44, 68); ascending aorta, 41 (29, 53); superior vena cava, 29 (15, 43); ductus arteriosus, 41 (25, 57); descending aorta, 55 (35, 75); pulmonary blood flow, 16 (0, 34); umbilical vein, 29 (11, 47); and foramen ovale, 29 (7, 51). A strong inverse relationship between foramen ovale shunt and pulmonary blood flow was noted (r=-0.64; P<0.0001). CONCLUSIONS: Although too small a sample size to provide normal ranges, these results are in keeping with those predicted in humans based on measurements made in fetal lambs using radioactive microspheres and provide preliminary reference ranges for the late-gestation human fetuses. The wide range we found in foramen ovale shunting suggests a degree of variability in the way blood is streamed through the fetal circulation.
Authors: B P Schoennagel; J Yamamura; F Kording; R Fischer; P Bannas; G Adam; H Kooijman; C Ruprecht; K Fehrs; M Tavares de Sousa Journal: Eur Radiol Date: 2019-01-07 Impact factor: 5.315
Authors: Esra Abaci Turk; Jeffrey N Stout; Christopher Ha; Jie Luo; Borjan Gagoski; Filiz Yetisir; Polina Golland; Lawrence L Wald; Elfar Adalsteinsson; Julian N Robinson; Drucilla J Roberts; William H Barth; P Ellen Grant Journal: Top Magn Reson Imaging Date: 2019-10
Authors: Liqun Sun; Christopher K Macgowan; John G Sled; Shi-Joon Yoo; Cedric Manlhiot; Prashob Porayette; Lars Grosse-Wortmann; Edgar Jaeggi; Brian W McCrindle; John Kingdom; Edward Hickey; Steven Miller; Mike Seed Journal: Circulation Date: 2015-03-11 Impact factor: 29.690