BACKGROUND Arterial pulse wave velocity (PWV) is associated with increased mortality in aging and disease. Several studies have shown the accuracy of applanation tonometry carotid-femoral PWV (Cf-PWV) and the relevance of evaluating central aorta stiffness using 2D cardiovascular magnetic resonance (CMR) to estimate PWV, and aortic distensibility-derived PWV through the theoretical Bramwell-Hill model (BH-PWV). Our aim was to compare various methods of aortic PWV (aoPWV) estimation from 4D flow CMR, in terms of associations with age, Cf-PWV, BH-PWV and left ventricular (LV) mass-to-volume ratio while evaluating inter-observer reproducibility and robustness to temporal resolution. METHODS We studied 47 healthy subjects (49.5 ± 18 years) who underwent Cf-PWV and CMR including aortic 4D flow CMR as well as 2D cine SSFP for BH-PWV and LV mass-to-volume ratio estimation. The aorta was semi-automatically segmented from 4D flow data, and mean velocity waveforms were estimated in 25 planes perpendicular to the aortic centerline. 4D flow CMR aoPWV was calculated: using velocity curves at two locations, namely ascending aorta (AAo) and distal descending aorta (DAo) aorta (S1, 2D-like strategy), or using all velocity curves along the entire aortic centreline (3D-like strategies) with iterative transit time (TT) estimates (S2) or a plane fitting of velocity curves systolic upslope (S3). For S1 and S2, TT was calculated using three approaches: cross-correlation (TTc), wavelets (TTw) and Fourier transforms (TTf). Intra-class correlation coefficients (ICC) and Bland-Altman biases (BA) were used to evaluate inter-observer reproducibility and effect of lower temporal resolution. RESULTS 4D flow CMR aoPWV estimates were significantly (p < 0.05) correlated to the CMR-independent Cf-PWV, BH-PWV, age and LV mass-to-volume ratio, with the strongest correlations for the 3D-like strategy using wavelets TT (S2-TTw) (R = 0.62, 0.65, 0.77 and 0.52, respectively, all p < 0.001). S2-TTw was also highly reproducible (ICC = 0.99, BA = 0.09 m/s) and robust to lower temporal resolution (ICC = 0.97, BA = 0.15 m/s). CONCLUSIONS Reproducible 4D flow CMR aoPWV estimates can be obtained using full 3D aortic coverage. Such 4D flow CMR stiffness measures were significantly associated with Cf-PWV, BH-PWV, age and LV mass-to-volume ratio, with a slight superiority of the 3D strategy using wavelets transit time (S2-TTw).

中文翻译：

---

通过 4D 血流心血管磁共振估计主动脉脉搏波速度的不同方法的比较。


背景技术动脉脉搏波速度(PWV)与衰老和疾病死亡率增加相关。多项研究表明，压平张力测量颈动脉-股动脉 PWV (Cf-PWV) 的准确性，以及使用 2D 心血管磁共振 (CMR) 评估中央主动脉硬度来估计 PWV 的相关性，以及通过理论 Bramwell-Hill 估计主动脉扩张性得出的 PWV 的相关性模型（BH-PWV）。我们的目的是比较 4D 血流 CMR 估计主动脉 PWV (aoPWV) 的各种方法与年龄、Cf-PWV、BH-PWV 和左心室 (LV) 质量体积比的关联，同时评估观察者间的情况时间分辨率的再现性和鲁棒性。方法 我们研究了 47 名健康受试者（49.5 ± 18 岁），他们接受了 Cf-PWV 和 CMR，包括主动脉 4D 血流 CMR 以及用于 BH-PWV 和 LV 质量体积比估计的 2D 电影 SSFP。主动脉根据 4D 血流数据半自动分割，并在垂直于主动脉中心线的 25 个平面中估计平均速度波形。 4D 血流 CMR aoPWV 计算：使用两个位置的速度曲线，即升主动脉 (AAo) 和远端降主动脉 (DAo) 主动脉（S1，类似 2D 策略），或使用沿整个主动脉中心线的所有速度曲线（3D-类似的策略）与迭代渡越时间（TT）估计（S2）或速度曲线收缩上坡（S3）的平面拟合。对于 S1 和 S2，TT 使用三种方法计算：互相关 (TTc)、小波 (TTw) 和傅立叶变换 (TTf)。组内相关系数 (ICC) 和 Bland-Altman 偏差 (BA) 用于评估观察者间的再现性和较低时间分辨率的影响。结果 4D 血流 CMR aoPWV 估计值显着 (p < 0.05) 与 CMR 无关的 Cf-PWV、BH-PWV、年龄和 LV 质量体积比相关，使用小波 TT (S2​​-TTw) 的类 3D 策略的相关性最强 (R = 0.62, 0.65分别为 0.77 和 0.52，所有 p < 0.001）。 S2-TTw 还具有高度可重复性（ICC = 0.99，BA = 0.09 m/s）并且对较低时间分辨率具有鲁棒性（ICC = 0.97，BA = 0.15 m/s）。结论 使用完整的 3D 主动脉覆盖可以获得可重复的 4D 血流 CMR aoPWV 估计值。这种 4D 血流 CMR 刚度测量与 Cf-PWV、BH-PWV、年龄和 LV 质量体积比显着相关，使用小波传输时间 (S2-TTw) 的 3D 策略稍有优势。