Validation framework for 4D perfusion computed tomography

动态对比增强计算机断层扫描（DCE-CT）是一种功能性成像工具，已应用于各种解剖部位，并显示具有诊断和预后价值。基本过程是静脉内施用的碘化造影剂的流动运输和这些造影剂分子在血管内和血管外空间之间的扩散。已经开发了用于对比材料交换的不同示踪剂动力学模型来量化微循环的生理特性。尽管DCE-CT相对成功，但这些参数的再现性和可靠定量一直很困难。其中一些主要原因是现代CT扫描仪的检测器设计提供的有限速度和覆盖范围、过于简单的示踪剂动力学算法以及对基本对比度交换特性的有限了解。在我们机构实施的新型CT扫描仪（Aquarium One，Toshiba）现在为第一个问题提供了解决方案，在0.35秒的单次旋转内，探测器在等中心处的覆盖范围为160 mm。因此，该建议旨在建立一个幻影模拟框架，在其中调查和验证已知的示踪剂动力学模型。其目标是设计和制造逼真的肺，肝和心血管系统的灌注模型，使用生物聚合物和组织保存。这将包括一个理论模拟部分，其中基本的毛细交换性能的特点，在可渗透介质中进行了研究与计算流体动力学。从长远来看，希望这将导致更准确的示踪剂动力学模型和改进的造影剂的发展，用于DCE成像，能够测量体内的生理特性。

Dynamic Contrast-Enhanced Computed Tomography (DCE-CT) is a functional imaging tool that has been applied to various anatomical sites and shown to have diagnostic and prognostic value. The underlying process is the flow transport of intravenously administered iodinated contrast agent and the diffusion of these contrast molecules between the intra-vascular and extra-vascular space. Different tracer kinetics models for contrast material exchange have been developed to quantify physiological properties of the microcirculation. Despite the relative successes of DCE-CT, the reproducibility and reliable quantification of these parameters has been difficult. Some of the main reasons for this are the limited speed and coverage afforded by the detector design of modern CT scanners, simplistic tracer kinetics algorithms; and a limited knowledge of fundamental contrast exchange properties. The implementation of a novel CT scanner (Aquilion One, Toshiba) at our institution now provides a solution to the first issue with detector coverage of 160 mm at the isocentre within a single rotation of 0.35 sec. This proposal therefore aims to establish a phantom simulation framework in which to investigate and validate known tracer kinetics models. The goal is to design and manufacture realistic perfusion phantoms of the lungs, liver and cardiovascular system, using biopolymers and tissue preservation. This will include a theoretical simulation component in which the characteristics of fundamental capillary exchange properties in permeable media are investigated with computational fluid dynamics. In the long term it is hoped this will lead to the development of more accurate tracer kinetics models and improved contrast agents for DCE imaging to be able to measure in vivo physiology characteristics.