Rapid Slice-to-Volume 4D Flow in Pediatric Patients with Congenital Heart Disease: A Feasibility Study.

Abstract

Background: Magnetic resonance imaging (MRI) allows cardiac hemodynamic assessment in patients with congenital heart disease. However, conventional techniques are time-consuming and may require blood contrast agents. Slice-to-volume reconstruction (SVR) 4D flow is an innovative imaging technique that may overcome those limitations. This study aimed to assess the feasibility of SVR 4D flow in pediatric congenital heart disease.

Methods: Patients with congenital heart disease (n=7, age=12.9±2.8 years) underwent cardiovascular magnetic resonance imaging with conventional 2D phase-contrast MRI (2D PCMRI) and SVR 4D flow. SVR 4D flow datasets were reconstructed from multi-slice 2D spiral PCMRI acquisitions, which were combined via slice-to-volume reconstruction. Mean flow in major thoracic vessels were measured and compared between the two techniques. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated in each participant and compared between imaging techniques.

Results: Linear regression for SVR 4D flow against 2D PCMRI showed good agreement in mean flows (slope=1.03, intercept=-5.31ml/s, r²=0.95). The SNR and CNR did not differ significantly between 2D PCMRI and SVR 4D flow data (SNR: p=0.85, CNR: p=0.90).

Conclusion: Our results suggest that SVR 4D flow MRI is a feasible 5-minute scan (relative to multiple 2D PCMRI prescriptions and scans) in pediatric patients with congenital heart disease. SVR 4D flow showed good agreement with 2D PCMRI for mean flow measurements. The advantages of SVR 4D flow MRI support further research such as its comparison with conventional 4D flow.