Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
J Magn Reson Imaging. 2020 Apr;51(4):1105-1116. doi: 10.1002/jmri.26934. Epub 2019 Oct 7.
Patients with transposition of the great arteries (TGA) have an altered aortic geometry after an arterial switch operation (ASO), with neo-aortic root dilatation as an important complication. Geometry-related aortic hemodynamics have been assumed to contribute to pathology of the ascending aorta (AAo).
To evaluate aortic flow displacement (FD) and regional wall shear stress (WSS) in relation to ascending neo-aortic geometry in children after ASO.
Prospective.
Twenty-eight TGA patients after ASO and 10 healthy volunteers.
FIELD STRENGTH/SEQUENCE: 3.0T/4D flow (segmented fast-spoiled echo pulse), noncontrast-enhanced MR angiography (Dixon), and anatomic images (SSFP).
Aortic diameters and body surface area-indexed aortic dimensions (Z-scores), normalized FD and planar ascending aortic WSS.
Mann-Whitney and chi-square tests for differences in FD magnitude, WSS, and FD directionality between groups, respectively. Spearman rank correlation to assess the degree of association between aortic geometry, FD and WSS parameters. Shapiro-Wilk test to evaluate distribution normality on the absolute differences in octant location between FD and WSS.
TGA patients showed a significantly dilated proximal AAo and relatively small mid-AAo dimensions at the level of the pulmonary arteries (Z-scores neo-aortic root: 4.38 ± 1.96 vs. 1.52 ± 0.70, P < 0.001; sinotubular junction: 3.48 ± 2.67 vs. 1.38 ± 1.30, P = 0.010; mid-AAo: 0.32 ± 3.06 vs. 1.69 ± 1.24, P = 0.001). FD magnitude was higher in TGA patients (neo-aortic root: 0.048 ± 0.027 vs. 0.021 ± 0.006, P < 0.001; sinotubular junction: 0.054 ± 0.037 vs. 0.029 ± 0.013, P < 0.05) and was related to the neo-aortic Z-score. Clear areas of higher WSS at the right and anterior aortic wall regions along the distal AAo were detected in TGA patients, most pronounced in those with relatively smaller mid-AAo diameters.
TGA-specific geometry related to the ASO, evidenced by neo-aortic root dilatation and a sudden change in vessel diameter at mid-AAo level, leads to more aortic flow asymmetry in the proximal AAo and WSS distribution with higher WSS at the right and anterior aortic wall regions along the distal AAo.
1 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:1105-1116.
大动脉转位（TGA）患者在接受大动脉调转术（ASO）后主动脉几何形状发生改变，新主动脉根部扩张是一个重要的并发症。主动脉几何形状相关的血流动力学已被认为与升主动脉（AAo）的病理学有关。
评估 TGA 患者 ASO 后主动脉根部和升主动脉的血流位移（FD）和局部壁面切应力（WSS）与升主动脉几何形状的关系。
前瞻性。
28 例 TGA 患者 ASO 后和 10 名健康志愿者。
磁场强度/序列：3.0T/4D 流（分段快速扰相回波脉冲）、非增强 MR 血管造影（Dixon）和解剖图像（SSFP）。
主动脉直径和体表面积指数化的主动脉尺寸（Z 分数）、标准化的 FD 和升主动脉平面 WSS。
采用 Mann-Whitney 和卡方检验分别比较两组之间 FD 幅度、WSS 和 FD 方向性的差异。Spearman 秩相关评估主动脉几何形状、FD 和 WSS 参数之间的关联程度。Shapiro-Wilk 检验评估 FD 和 WSS 之间的八角区位置绝对差值的分布正态性。
TGA 患者近端 AAo 明显扩张，肺动脉水平的中 AAo 直径相对较小（Z 分数新主动脉根部：4.38 ± 1.96 vs. 1.52 ± 0.70，P < 0.001；窦管交界：3.48 ± 2.67 vs. 1.38 ± 1.30，P = 0.010；中 AAo：0.32 ± 3.06 vs. 1.69 ± 1.24，P = 0.001）。TGA 患者的 FD 幅度更高（新主动脉根部：0.048 ± 0.027 vs. 0.021 ± 0.006，P < 0.001；窦管交界：0.054 ± 0.037 vs. 0.029 ± 0.013，P < 0.05），与新主动脉 Z 分数相关。在 TGA 患者中，在远端 AAo 的右前主动脉壁区域检测到更高的 WSS 的清晰区域，在中 AAo 直径较小的患者中最为明显。
ASO 导致 TGA 患者特有的与几何形状相关的病变，表现为新主动脉根部扩张和中 AAo 水平的血管直径突然变化，导致近端 AAo 中的主动脉血流不对称性增加，以及远端 AAo 的右前主动脉壁区域的 WSS 分布更高。
1 技术功效阶段：3 J. Magn. Reson. Imaging 2020;51:1105-1116.
