Abstract 6078: Comparison of Power Losses, Hepatic Flow Splits, and Vortex Sizes in Different Fontan Types Using Non Invasive Phase Contrast Magnetic Resonance Imaging
Non-invasive estimation of power losses (PL), hepatic to pulmonary flow splits (HFS), and vortex sizes (VS) have important application in the clinical assessment of Fontan geometries. This paper introduces a new approach for the direct evaluation of these parameters in vivo using phase-contrast (PC) MRI. 32 Fontan pts(7.66 ±4.4 yrs) underwent 3D PC MR imaging at two high volume children’s institutions (Institution 1 n=28, Institution 2 n=4) featuring 16 lateral tunnels (LT), 12 extra cardiacs (ECs), and 4 interrupted inferior vena cava with an azygous vein continuation (IIVC). Using a novel, fully-validated, divergence free interpolation technique, the 4D velocity field within the Fontan was reconstructed. PLs, HFS, and VS were then directly evaluated using this velocity field. LTs (Fig a–b⇓) had significantly larger vortices (p < 0.05) compared to ECs (Fig c⇓) and IIVCs (Fig d⇓). Direction of the vortex differed based on the type of second stage surgery for the LT case (Fig a⇓: LT-Hemi Fontan and Fig b⇓: LT- Bidirectional Glenn). PLs were highest in IIVCs followed by ECs and LTs. Both LTs and ECs had uniform HFS that differed significantly from the IIVCs (p <0.05). A new method for evaluating PL, HFS, and VS in vivo is presented. A comparison across various Fontan templates revealed significant differences in PLs, HFS, and VS across different templates.
This research has received full or partial funding support from the American Heart Association, AHA Greater Southern Affiliate (Alabama, Florida, Georgia, Louisiana, Mississippi, Puerto Rico & Tennessee).