Departments of Fundamental Development for Low Invasive Diagnostic Imaging and Radiology, Nagoya University Graduate School of Medicine.
Magn Reson Med Sci. 2022 Mar 1;21(2):354-364. doi: 10.2463/mrms.rev.2021-0156. Epub 2022 Feb 18.
Blood vessels can be regarded as autonomous organs. The endothelial cells on the vessel surface serve as mechanosensors or mechanoreceptors for the flow velocity and turbulence of the blood flow in terms of wall shear stress (WSS), thereby monitoring changes in the flow velocity. Accordingly, the endothelial cells regulate the flow velocity by releasing numerous mediators. Such regulatory systems also trigger atherosclerosis, where the WSS decreases or fluctuates to maintain the flow velocity or local WSS. As occurrences of abdominal aortic aneurysms and aortic dissection are closely related to atherosclerosis, understanding the hemodynamics of the abdominal aorta is necessary to obtain useful information concerning the pathogenesis, diagnosis, and interventions. 4D flow MRI is beneficial for measuring the hemodynamics through comprehensive retrospective flowmetry of the entire spatio-temporal distributions of the flow vectors. This section focuses on abdominal aortic aneurysms and aortic dissection as representative examples of abdominal aortic diseases. Their hemodynamic characteristics and how hemodynamics is involved in their progression are described, and how 4D flow MRI can contribute to their assessment is also explained.
血管可以被视为自主器官。血管表面的内皮细胞作为血流速度和壁切应力（WSS）的血流湍流的力感受器或机械感受器，从而监测血流速度的变化。相应地，内皮细胞通过释放众多介质来调节血流速度。这种调节系统还会引发动脉粥样硬化，其中壁切应力降低或波动以维持血流速度或局部壁切应力。由于腹主动脉瘤和主动脉夹层的发生与动脉粥样硬化密切相关，因此了解腹主动脉的血流动力学对于获得有关发病机制、诊断和干预的有用信息是必要的。4D 流 MRI 通过对整个流矢量时空分布的全面回顾性流量测量，有利于测量血流动力学。本节以腹主动脉瘤和主动脉夹层作为腹主动脉疾病的代表性示例，重点介绍它们的血流动力学特征以及血流动力学如何参与其进展，并解释 4D 流 MRI 如何有助于其评估。
