INTRAVASCULAR IN VIVO CATHETER-BASED ULTRASOUND

小血管的标准成像模式具有固有的局限性， 无法表征横截面壁几何形状或透壁血管壁 病理因此，小型化血管内超声的使用 成为表征动脉壁形态的新兴成像技术 并监测经导管手术。我们正在与各种各样的 微型原型柔性导管（1.5 mm）能够产生高 放置在血管内后的径向分辨率超声图像。到 为了研究这种新成像系统的可行性和实用性， 在绵羊中成像，血管壁尺寸与对比度相关 动脉造影此外，超声检查金属支架后， 进行植入是为了确定超声因素， 可能有助于评估支架植入的充分性。我们发现了一个 血管造影和超声血管壁之间的显著相关性 直径，但注意到来自超声的重要附加信息 包括横截面积、管腔几何形状、透壁厚度和 心动周期中的外观和脉动变化表明 血管壁顺应性。金属支架很容易可视化， 与支架放置相关的因素可能具有临床重要性。的 存在或不存在管腔内充盈缺损， 周向支架扩张和支架动脉壁接触都是 可以使用超声技术容易地识别的变量。 因此，在这项初步的体内研究中，我们感到鼓舞的是， 基于导管的超声成像技术将是一种重要的模式 以帮助表征血管壁几何形状和病理学。

Standard imaging modalities of small vessels have inherent limitations and cannot characterize cross-sectional wall geometry or transmural vessel wall pathology. Therefore the use of miniaturized intravascular ultrasound has become an emerging imaging technique to characterize artery wall morphology and to monitor transcatheter procedures. We are working with a variety of miniature prototype flexible catheters (1.5mm) capable of generating high radial resolution ultrasound images after placement within the vessel. To study the feasibility and utility of this new imaging system, arteries were imaged in sheep and vessel wall dimensions were correlated with contrast angiography. In addition, ultrasound examination of metallic stents after implantation was performed in an effort to define ultrasound factors which might help in assessing the adequacy of stent implantation. We found a striking correlation between angiographic and ultrasound vessel wall diameter but noted important additional information from ultrasound including cross-sectional area, lumen geometry, transmural thickness and appearance, and pulsatile changes during the cardiac cycle suggesting vessel wall compliance. Metallic stents were easily visualized and several factors relating to stent placement might be of clinical importance. The presence or absence of intraluminal filling defects, the adequacy of circumferential stent expansion, and stent artery wall contact are all variables which can be identified easily using ultrasound techniques. Therefore, in this preliminary in vivo study we feel encouraged that catheter-based ultrasound imaging techniques will be an important modality to help characterized vessel wall geometry and pathology.