Phase‐contrast magnetic resonance quantification of normal pulmonary venous return

Abstract

Purpose:To assess the feasibility of phase-contrast magnetic resonance (PCMR) in quantifying the pulmonary venous return in normal subjects. Materials and Methods:PCMR was performed in 12 healthy adult volunteers (mean age 38 years, range 27-60 years; 9 men; body surface area 1.81 Ϯ 0.15 m 2 ) for the ascending and descending aorta, caval veins, main and branch pulmonary arteries, and pulmonary veins. Two readers independently quantified blood flow in all subjects.Results: Intraobserver differences were Ϫ2.0% (95% confidence interval [CI]: Ϫ9.9% to 5.9%), Ϫ4.5% (95% CI: Ϫ15.6% to 6.5%), and Ϫ0.7% (95% CI: Ϫ4.5% to 3.0%) for all vessels, pulmonary veins, and other great vessels, respectively. Interobserver differences were Ϫ2.0% (95% CI: Ϫ10.6% to 6.6%), Ϫ3.1% (95% CI: Ϫ16.0% to 9.9%), and Ϫ1.4% (95% CI: Ϫ6.4% to 3.5%) for all vessels, pulmonary veins, and other great vessels, respectively. Pulmonary venous flow volume showed high correlations with the volumes of the pulmonary arterial flow, systemic arterial flow, and systemic venous flow (r ϭ 0.76 -0.92, P Ͻ 0.005). Conclusion:Flow quantification of normal pulmonary venous return using PCMR is feasible with high reproducibility and accuracy. FLOW QUANTIFICATION using the phase-contrast (or velocity-encoded) technique is a central part of comprehensive cardiac magnetic resonance (MR) imaging for congenital heart disease in children and adults. Phasecontrast MR imaging (PCMR) has been validated as accurate in evaluating velocity, volume, and pattern of pulsatile blood flow (1-5). Flow measurements using PCMR have been used at various great vessels, including the aorta, the pulmonary artery, and the superior and inferior vena cavae, in various clinical settings (6 -10). In contrast, feasibility of flow quantification of the pulmonary veins using PCMR has not been evaluated. As in systemic circulation, information on pulmonary venous flow in addition to pulmonary arterial flow is crucial for the full understanding of pulmonary circulation.Measurement of pulmonary venous flow is important in the following clinical scenarios: direct measurement of systemic collateral arterial flow to the lung; shunting involving the pulmonary vein; and alternative measurement of pulmonary arterial flow when it is not available for any reason. Attention with regard to evaluation of pulmonary vein abnormalities after radiofrequency ablation has also increased recently. However, it is very difficult to provide accurate quantification of pulmonary venous flow when using echocardiography and the catheter technique. This fact motivated our study because noninvasive PCMR has great potential in offering such pulmonary venous flow data. A few clinical studies have demonstrated the usefulness of quantification of pulmonary venous flow volume with PCMR in patients with anomalous pulmonary venous connection, stenotic pulmonary artery with or without a stent, and systemic collateral arteries supplying the lungs (11-13). The amount of systemic collateral arterial supply to the lungs can be calcula...

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