健康成年人升主动脉形态和流动力学的年龄相关性变化：4D 血流 MRI 研究。
Age-related changes of shape and flow dynamics in healthy adult aortas: A 4D flow MRI study.
机构信息
Sydney Translational Imaging Laboratory, Heart Research Institute, Charles Perkins Centre, University of Sydney, Australia.
Sydney Medical School, University of Sydney, Camperdown, Australia.
出版信息
J Magn Reson Imaging. 2019 Jan;49(1):90-100. doi: 10.1002/jmri.26210. Epub 2018 Aug 13.
BACKGROUND
Abnormal flow dynamics play an early and causative role in pathologic changes of the ascending aorta.
PURPOSE
To identify: 1) the changes in flow, shape, and size that occur in the ascending aorta with normal human ageing and 2) the influence of these factors on aortic flow dynamics.
STUDY TYPE
Retrospective.
SUBJECTS
In all, 247 subjects (age range 19-86 years, mean 49 ± 17.7, 169 males) free of aortic or aortic valve pathology were included in this study. Subjects were stratified by youngest (18-33 years; n = 64), highest (>60 years, n = 67), and the middle two quartiles (34-60 years, n = 116).
FIELD STRENGTH/SEQUENCE: Subjects underwent a cardiac MRI (3T) exam including 4D-flow MRI of the aorta.
ASSESSMENT
Aortic curvature, arch shape, ascending aortic angle, ascending aortic diameter, and the stroke volume normalized by the aortic volume (nSV) were measured. Velocity, vorticity, and helicity were quantified across the thoracic aorta.
STATISTICAL TESTS
Univariate and multivariate regressions were used to quantify continuous relationships between variables.
RESULTS
Aortic diameter, ascending aortic angle, shape, and curvature all increased across age while nSV decreased (all P < 0.0001). Systolic vorticity in the mid arch decreased by 50% across the age range (P < 0.0001), while peak helicity decreased by 80% (P < 0.0001). Curvature tightly governs optimal flow in the youngest quartile, with an effect size 1.5 to 4 times larger than other parameters in the descending aorta, but had a minimal influence with advancing age. In the upper quartile of age, flow dynamics were almost completely determined by nSV, exerting an effect size on velocity and vorticity >10 times that of diameter and other shape factors.
DATA CONCLUSION
Aortic shape influences flow dynamics in younger subjects. Flow conditions become increasingly disturbed with advancing age, and in these conditions nSV has a more dominant effect on flow patterns than shape factors.
LEVEL OF EVIDENCE
3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:90-100.
背景
异常的流动动力学在升主动脉的病理变化中起着早期和因果的作用。
目的
确定 1）在正常人类衰老过程中升主动脉中发生的流动、形状和大小的变化，以及 2）这些因素对主动脉流动动力学的影响。
研究类型
回顾性。
受试者
本研究共纳入 247 名无主动脉或主动脉瓣病变的受试者（年龄范围 19-86 岁，平均 49±17.7 岁，男性 169 名）。受试者按最年轻（18-33 岁；n=64）、最高（>60 岁，n=67）和中间两个四分位数（34-60 岁，n=116）分层。
磁场强度/序列：受试者接受心脏 MRI（3T）检查，包括主动脉 4D-flow MRI。
评估
测量主动脉曲率、弓形状、升主动脉角度、升主动脉直径和主动脉容积标准化的每搏量（nSV）。在胸主动脉上量化速度、涡度和螺旋度。
统计学检验
使用单变量和多变量回归来量化变量之间的连续关系。
结果
随着年龄的增长，主动脉直径、升主动脉角度、形状和曲率均增加，而 nSV 降低（均 P<0.0001）。中弓的收缩期涡度在整个年龄范围内降低了 50%（P<0.0001），而峰值螺旋度降低了 80%（P<0.0001）。曲率在最年轻的四分位数中严格控制最佳流动，其效应大小是降主动脉中其他参数的 1.5 到 4 倍，但随着年龄的增长影响很小。在上四分位数年龄组中，流动动力学几乎完全由 nSV 决定，对速度和涡度的影响大小是直径和其他形状因素的 10 倍以上。
数据结论
主动脉形状影响年轻受试者的流动动力学。随着年龄的增长，流动条件变得越来越紊乱，在这些条件下，nSV 对流动模式的影响大于形状因素。
证据水平
3 技术功效：第 1 阶段 J. Magn. Reson. Imaging 2019;49:90-100。
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