Additional value and new insights by four-dimensional flow magnetic resonance imaging in congenital heart disease: application in neonates and young children

Julia Geiger,Emanuela R Valsangiacomo Buechel,Fraser M Callaghan,Barbara E U Burkhardt,Christian J Kellenberger

doi:10.1007/s00247-020-04885-w

Abstract

Cardiovascular MRI has become an essential imaging modality in children with congenital heart disease (CHD) in the last 15–20 years. With use of appropriate sequences, it provides important information on cardiovascular anatomy, blood flow and function for initial diagnosis and post-surgical or -interventional monitoring in children. Although considered as more sophisticated and challenging than CT, in particular in neonates and infants, MRI is able to provide information on intra- and extracardiac haemodynamics, in contrast to CT. In recent years, four-dimensional (4-D) flow MRI has emerged as an additional MR technique for retrospective assessment and visualisation of blood flow within the heart and any vessel of interest within the acquired three-dimensional (3-D) volume. Its application in young children requires special adaptations for the smaller vessel size and faster heart rate compared to adolescents or adults. In this article, we provide an overview of 4-D flow MRI in various types of complex CHD in neonates and infants to demonstrate its potential indications and beneficial application for optimised individual cardiovascular assessment. We focus on its application in clinical routine cardiovascular workup and, in addition, show some examples with pathologies other than CHD to highlight that 4-D flow MRI yields new insights in disease understanding and therapy planning. We shortly review the essentials of 4-D flow data acquisition, pre- and post-processing techniques in neonates, infants and young children. Finally, we conclude with some details on accuracy, limitations and pitfalls of the technique.

Highlights

Cardiovascular MRI has become a complementary modality to echocardiography and a valuable alternative to conventional Xray angiography and CT in neonates and young children with congenital heart disease (CHD) for preoperative assessment of cardiovascular anatomy and function and for follow-up after interventions or cardiovascular surgery [1,2,3,4]
Because 4-D flow MRI enables flow visualisation and quantification within a large three-dimensional (3-D) volume covering almost the entire thorax, its application in paediatric CHD helps to increase our understanding of the mechanisms and the significance of abnormal blood flow patterns
We demonstrate some examples in which 4-D flow MRI provided valuable information concerning shunt quantification in cases with abnormal vasculature

Summary

Introduction

Cardiovascular MRI has become a complementary modality to echocardiography and a valuable alternative to conventional Xray angiography and CT in neonates and young children with congenital heart disease (CHD) for preoperative assessment of cardiovascular anatomy and function and for follow-up after interventions or cardiovascular surgery [1,2,3,4]. It allows for flow volume quantification in small pulmonary arteries in which 2-D phase-contrast measurements failed (Fig. 8) It facilitates retrospective and comprehensive flow assessment, in children with Fontan palliation in whom multiple evaluation planes are required (Fig. 9). Ventricular volumes and ejection fraction correlated well in a study by Hsiao et al [22] comparing 4-D flow MRI with both 2-D phase-contrast and cine short-axis stack steady-state free precession results This group could demonstrate that the accuracy and precision of venous flow quantification are comparable to that of arterial flow quantification at velocityencodings appropriate for arterial vessels [51].

Limitations and pitfalls

Conflicts of interest None