Validation framework for 4D perfusion computed tomography

动态对比增强计算机断层扫描 (DCE-CT) 是一种功能成像工具，已应用于各种解剖部位，并被证明具有诊断和预后价值。基本过程是静脉注射碘造影剂的流动传输以及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，但这些参数的可重复性和可靠量化一直很困难。造成这种情况的一些主要原因是现代 CT 扫描仪的探测器设计、简单化的示踪动力学算法所提供的速度和覆盖范围有限；对基本对比交换特性的了解有限。我们机构采用的新型 CT 扫描仪（Aquilion One，东芝）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，等中心点的探测器覆盖范围为 160 毫米。因此，该提案旨在建立一个模型模拟框架，用于研究和验证已知的示踪剂动力学模型。目标是利用生物聚合物和组织保存来设计和制造逼真的肺、肝和心血管系统灌注模型。这将包括一个理论模拟部分，其中通过计算流体动力学研究可渗透介质中基本毛细管交换特性的特征。从长远来看，希望这将导致开发更准确的示踪动力学模型和改进的 DCE 成像造影剂，以便能够测量体内生理学特征。

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.