4D flow cardiac magnetic resonance in pediatric congenital heart disease: Insights from over four years of clinical practice

Background: Congenital heart diseases (CHDs) are common birth defects. This work presents over four years of clinical experience of 4D flow cardiovascular magnetic resonance (CMR), highlighting its value for pediatric CHD. Methods: Children with various CHD diagnoses (n = 298) were examined on a 1.5 or 3 T scanner using 4D flow CMR in free breathing with respiratory compensation. The image volume was acquired in axial orientation, covering the entire heart and major vessels. Head-to-head comparisons with reference standards were systematically performed. Results: 4D flow CMR provided more detailed insights into complex cardiovascular conditions while maintaining a comparable level of accuracy in peak velocity, Q and Qp/Qs (R = 0.9-1.0) compared to conventional 2D flow CMR. The advantages of 4D flow CMR were particularly evident for valve function, stenosis, and shunt assessments. However, our findings emphasize the need for additional corrections to address partial volume (up to 180 % error in perfusion ratio) and through-plane cardiac motion effects (up to 25/10 ml error in aortic/pulmonary regurgitation volume). Conclusion: Overall, 4D flow CMR proved to be a comprehensive diagnostic tool that enhanced the understanding and management of pediatric CHD, potentially changing the course of the treatment.