Lee T-Y, Purdie T G, Stewart E
Imaging Program, Lawson Health Research Institute, London, Ontario, Canada.
Q J Nucl Med. 2003 Sep;47(3):171-87.
Tumor angiogenesis has significant implications in the diagnosis and treatment of various solid tumors. With the advent of fast, multi-slice CT scanners, CT imaging techniques capable of qualitative and quantitative analysis of tumor angiogenesis have been the subject of extensive investigation in the past 2 decades. The fundamental bases for CT imaging of angiogenesis are both the transport by blood flow of intravenously administered iodinated contrast material to tissue and the exchange by diffusion of these contrast molecules between the intravascular space and the extravascular interstitial space. With current fast CT scanners both tissue and vascular enhancement can be measured and traced over time at small time intervals to allow detailed modeling of the distribution of contrast agent in tissue. Both compartmental and distributed parameter models for contrast transport and exchange have been developed to quantify from the CT data the following angiogenesis related parameters: tissue blood flow, blood volume, mean transit time, contrast arrival time, capillary permeability surface area product and hepatic arterial fraction in case of the liver. This review addresses the following aspects of CT imaging of angiogenesis: 1) basic concepts related to the understanding of both compartmental and distributed parameter models; 2) comparison between both types of models; 3) practical issues with respect to the measurement of the arterial input function, which is required for the solution of both types of models; and, 4) illustration of the application of a distributed parameter model, the Johnson and Wilson model, in a number of experimental studies.
肿瘤血管生成在各种实体瘤的诊断和治疗中具有重要意义。随着快速多层CT扫描仪的出现，能够对肿瘤血管生成进行定性和定量分析的CT成像技术在过去20年里一直是广泛研究的对象。血管生成CT成像的基本基础包括静脉注射碘化造影剂通过血流运输到组织，以及这些造影剂分子在血管内空间和血管外间质空间之间通过扩散进行交换。利用当前的快速CT扫描仪，可以在小时间间隔内随时间测量和追踪组织和血管的强化情况，以便对造影剂在组织中的分布进行详细建模。已经开发了用于造影剂运输和交换的房室模型和分布参数模型，以从CT数据中量化以下与血管生成相关的参数：组织血流量、血容量、平均通过时间、造影剂到达时间、毛细血管通透表面积乘积以及肝脏的肝动脉分数。本综述阐述了血管生成CT成像的以下几个方面：1）与理解房室模型和分布参数模型相关的基本概念；2）两种模型类型之间的比较；3）求解两种模型所需的动脉输入函数测量方面的实际问题；4）在一些实验研究中应用分布参数模型（约翰逊和威尔逊模型）的示例。
