Division of Cardiology, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
Arterioscler Thromb Vasc Biol. 2013 Jun;33(6):1306-12. doi: 10.1161/ATVBAHA.113.301312. Epub 2013 Apr 11.
Velocity-vector imaging (VVI) represents a valuable new method for noninvasive quantification of vascular properties associated with aging. The purpose of this study was to assess the correlations between VVI parameters and histological changes with aging.
Fourteen mongrel dogs were classified as either young (n=7; age, 1-2 years; female; weighing 22-29 kg) or senescent (n=7; age, 8-12 years; female; weighing 36-45 kg). The short-axis image of the descending thoracic aorta was obtained for VVI analysis with transesophageal echocardiography. The location of the image was identified using fluoroscopic guidance, and the aortic tissue was extracted. After dividing the aortic wall into 6 segments, both regional and segmental tissue collagen and elastin contents were quantified and correlated with the aortic elastic properties. In the regional analysis, the M-mode-derived aortic dimensions and elastic moduli except for intima-media thickness were not significantly different between the groups, whereas the VVI-derived aortic area and fractional area changes showed more dilated and stiffer aorta in senescent dogs. Also, fractional area change was significantly correlated with the tissue collagen content unlike the M-mode-derived elastic moduli. In the segmental analysis, the radial velocity, circumferential strain, and strain rates of VVI were more reduced in senescent dogs than young dogs, and the radial velocity and circumferential strain showed independent associations with the collagen content of the corresponding aortic wall.
VVI was a feasible method for direct quantification of aortic elastic properties with a significant histological correlation.
速度向量成像（VVI）代表了一种评估与衰老相关的血管特性的新的非侵入性方法。本研究旨在评估 VVI 参数与组织学变化随年龄变化的相关性。
14 只杂种狗分为年轻组（n=7；年龄 1-2 岁；女性；体重 22-29kg）和衰老组（n=7；年龄 8-12 岁；女性；体重 36-45kg）。使用经食管超声心动图获得降胸主动脉短轴 VVI 分析图像。在荧光透视引导下确定图像位置，并提取主动脉组织。将主动脉壁分为 6 个节段后，对每个节段的组织胶原和弹性蛋白含量进行定量，并与主动脉弹性特性相关联。在区域性分析中，两组之间 M 模式衍生的主动脉尺寸和弹性模量（除了内中膜厚度）没有显著差异，而 VVI 衍生的主动脉面积和面积变化分数显示衰老狗的主动脉更扩张和更僵硬。此外，面积变化分数与组织胶原含量显著相关，而与 M 模式衍生的弹性模量无关。在节段性分析中，VVI 的径向速度、周向应变和应变率在衰老狗中比年轻狗更低，径向速度和周向应变与相应主动脉壁的胶原含量具有独立的关联。
VVI 是一种直接定量评估主动脉弹性特性的可行方法，与组织学变化具有显著相关性。
