Becker A E
Department of Pathology, Academic Medical Center, Amsterdam-Zuidoost, The Netherlands.
Int J Card Imaging. 1989;4(2-4):99-104. doi: 10.1007/978-94-009-1007-2_3.
The in vivo detection of early atherosclerosis remains a problem. First, atherogenesis is a process with an insidious onset and course. Once clinical signs and symptoms have developed the lesion usually is in an advanced stage. Second, the detection of early atherosclerotic lesions creates the problem of distinguishing between almost natural, age-related intimal changes and intimal thickening as a precursor lesion of atherosclerosis. The hallmark of atherosclerosis is the abnormal deposition of lipids within the intima. This process is accompanied by a cellular response, composed of macrophages, lymphocytes and proliferating vascular smooth muscle cells. An increasing quantity of collagen and elastin fibers eventually will replace the cellular constituents. In other words, a changing histological picture with respect to component make up in time. Third, an adequate interpretation of intimal thickening may be complicated further by tissue characteristics of the arterial media. The elastin units of an elastic type artery produce an echo-dense image, whereas a muscular media is hypoechoic. All in all it seems fair to state that ultrasound imaging techniques, at least for the time being, will be inadequate to distinguish between 'early' atherosclerotic lesions and intimal thickenings which will not necessarily progress to the full blown lesion.
早期动脉粥样硬化的体内检测仍然是一个问题。首先，动脉粥样硬化的发生是一个起病隐匿、病程缓慢的过程。一旦出现临床症状，病变通常已处于晚期。其次，早期动脉粥样硬化病变的检测存在一个问题，即难以区分几乎自然的、与年龄相关的内膜变化和作为动脉粥样硬化前驱病变的内膜增厚。动脉粥样硬化的标志是脂质在内膜中的异常沉积。这个过程伴随着由巨噬细胞、淋巴细胞和增殖的血管平滑肌细胞组成的细胞反应。最终，越来越多的胶原蛋白和弹性纤维将取代细胞成分。换句话说，随着时间的推移，组织构成方面的组织学图像会发生变化。第三，动脉中膜的组织特性可能会进一步使对内膜增厚的恰当解释变得复杂。弹性型动脉的弹性单元产生回声密集图像，而肌性中膜则为低回声。总而言之，似乎可以说，至少目前，超声成像技术不足以区分“早期”动脉粥样硬化病变和不一定会发展为典型病变的内膜增厚。
