Open Access

ARTICLE

Comparative Evaluation of Flow Quantification across the Atrioventricular Valve in Patients with Functional Univentricular Heart after Fontan’s Surgery and Healthy Controls: Measurement by 4D Flow Magnetic Resonance Imaging and Streamline Visualization

Hoi Lam She^*, Arno A.W. Roest^†, Emmeline E. Calkoen^†, Pieter J. van den Boogaard^‡, Rob J. van der Geest^‡, Mark G. Hazekamp^§, Albert de Roos^‡, Jos J.M. Westenberg^‡

* Department of Radiology, Princess Margaret Hospital, Hong Kong SAR
† Division of Pediatric Cardiology, Department of Pediatrics
‡ Department of Radiology
§ Department of Thoracic Surgery, Leiden University Medical Center, Leiden, The Netherlands

* Corresponding Author: Hoi Lam She. ; Princess Margaret Hosp, Dept Radiol, Hong Kong, Hong Kong,

Congenital Heart Disease 2017, 12(1), 40-48.

Abstract

Purpose. To evaluate the inflow pattern and flow quantification in patients with functional univentricular heart after Fontan’s operation using 4D flow magnetic resonance imaging (MRI) with streamline visualization when compared with the conventional 2D flow approach.
Method. Seven patients with functional univentricular heart after Fontan’s operation and twenty-three healthy controls underwent 4D flow MRI. In two orthogonal two-chamber planes, streamline visualization was applied, and inflow angles with peak inflow velocity (PIV) were measured. Transatrioventricular flow quantification was assessed using conventional 2D multiplanar reformation (MPR) and 4D MPR tracking the annulus and perpendicular to the streamline inflow at PIV, and they were validated with net forward aortic flow.
Results. Inflow angles at PIV in the patient group demonstrated wide variation of angles and directions when compared with the control group (P < .01). The use of 4D flow MRI with streamlines visualization in quantification of the transatrioventricular flow had smaller limits of agreement (2.2 ± 4.1 mL; 95% limit of agreement 25.9–10.3 mL) when compared with the static plane assessment from 2DFlow MRI (22.2 ± 18.5 mL; 95% limit of agreement agreement 238.5-34.1 mL). Stronger correlation was present in the 4D flow between the aortic and transatrioventricular flow (R² correlation in 4D flow: 0.893; in 2D flow: 0.786).
Conclusions. Streamline visualization in 4D flow MRI confirmed variable atrioventricular inflow directions in patients with functional univentricular heart with previous Fontan’s procedure. 4D flow aided generation of measurement planes according to the blood flood dynamics and has proven to be more accurate than the fixed plane 2D flow measurements when calculating flow quantifications.

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