Systemic-to-pulmonary collateral flow is a well-recognised phenomenon in patients with single ventricle physiology, but remains difficult to quantify. The aim was to compare the reported formula’s that have been used for calculation of systemic-to-pulmonary-collateral flow to assess their consistency and to quantify systemic-to-pulmonary collateral flow in patients with a Glenn and/or Fontan circulation using four-dimensional flow MRI (4D flow MR).

Retrospective case–control study of Glenn and Fontan patients who had a 4D flow MR study. Flows were measured at the ascending aorta, left and right pulmonary arteries, left and right pulmonary veins, and both caval veins. Systemic-to-pulmonary collateral flow was calculated using two formulas: 1) pulmonary veins – pulmonary arteries and 2) ascending aorta – caval veins. Anatomical identification of collaterals was performed using the 4D MR image set.

Fourteen patients (n = 11 Fontan, n = 3 Glenn) were included (age 26 [22–30] years). Systemic-to-pulmonary collateral flow was significantly higher in the patients than the controls (n = 10, age 31.2 [15.1–38.4] years) with both formulas: 0.28 [0.09–0.5] versus 0.04 [−0.66–0.21] l/min/m2 (p = 0.036, formula 1) and 0.67 [0.24–0.88] versus -0.07 [−0.16–0.08] l/min/m2 (p < 0.001, formula 2). In patients, systemic-to-pulmonary collateral flow differed significantly between formulas 1 and 2 (13% versus 26% of aortic flow, p = 0.038). In seven patients, veno-venous collaterals were detected and no aortopulmonary collaterals were visualised.

4D flow MR is able to detect increased systemic-to-pulmonary collateral flow and visualise collaterals vessels in Glenn and Fontan patients. However, the amount of systemic-to-pulmonary collateral flow varies with the formula employed. Therefore, further research is necessary before it could be applied in clinical care.

全身至肺的侧支血流是单心室生理学患者中众所周知的现象，但仍然难以量化。目的是比较已报告的用于计算全身至肺侧支流量的公式，以评估其一致性，并使用四-量化格伦和/或 Fontan 循环患者的全身至肺侧支流量。三维流 MRI（4D 流 MR）。

对进行 4D 血流 MR 研究的 Glenn 和 Fontan 患者进行回顾性病例对照研究。测量升主动脉、左肺动脉和右肺动脉、左肺静脉和右肺静脉以及两个腔静脉的流量。使用两个公式计算全身至肺的侧支流量：1) 肺静脉 - 肺动脉和 2) 升主动脉 - 腔静脉。使用 4D MR 图像集对络脉进行解剖学识别。

纳入 14 名患者（n = 11 Fontan，n = 3 Glenn）（年龄 26 [22-30] 岁）。患者的全身至肺侧支流量显着高于对照组（n = 10，年龄 31.2 [15.1–38.4] 岁），两个公式分别为：0.28 [0.09–0.5] 与 0.04 [−0.66–0.21] l/ min/m 2（p = 0.036，公式 1）和 0.67 [0.24–0.88] 与 -0.07 [−0.16–0.08] l/min/m 2（p < 0.001，公式 2）。在患者中，公式 1 和 2 之间的全身至肺侧支血流存在显着差异（主动脉血流的 13% 与 26%，p = 0.038）。在七名患者中，检测到静脉-静脉侧支循环，但未观察到主肺侧支循环。

4D 血流 MR 能够检测 Glenn 和 Fontan 患者全身至肺部侧支血流的增加并可视化侧支血管。然而，全身至肺的侧支流量随所采用的公式而变化。因此，在应用于临床护理之前，还需要进一步研究。