Investigating the effect of cannulation on blood flow during extracorporeal membrane oxygenation using positron emission particle tracking

体外膜肺氧合（ECMO）是一种挽救生命的技术，可以为心脏和呼吸功能障碍患者提供支持。根据患者的需要使用ECMO的不同变体，但这些都依赖于特定血管的插管。虽然ECMO已成功地用作生命支持的一种形式超过30年，但在治疗过程中可能会出现并发症，这会显着增加死亡率。对于其中许多并发症，对原因的了解有限，因此难以提出和找到解决方案。当使用ECMO治疗患者时，插管的插入角度将根据具体情况而变化。这将影响来自插管和插管周围的流动，并且因此找到最佳角度可以使流动中的湍流最小化，并且因此减少并发症（诸如血凝块）的发生。此外，临床环境中使用的插管的说明书仅提供了通过插管的水流量的测量值，单位为L/min。本项目的目的是以更高的精度研究这种系统中的血流，进而深入了解一些常见并发症的潜在原因。为此，可以使用正电子发射粒子跟踪（PEPT）来获得通过插管和模型血管系统的实验流量测量。PEPT是伯明翰大学首创的一种成像技术，用于跟踪单个放射性标记示踪粒子的运动。第一轮实验已经进行，同时系统地改变插管的插入角度和模型系统中使用的流体。与实验工作平行，正在开发使用计算流体动力学（CFD）的系统的数值模拟。这些模拟将与实验结果进行比较，随后用于测试更复杂的系统。首先，实验和模拟数据将使用现有的方法进行分析。在此之后，将开展工作，探索将拓扑方法纳入重建和分析算法的潜在好处。

Extracorporeal membrane oxygenation (ECMO) is a life-saving technique that can provide support for patients with both cardiac and respiratory dysfunction. Different variations of ECMO are used depending on the needs of the patient, but these all rely on the cannulation of particular blood vessels. Although ECMO has been successfully used as a form of life support for over 30 years, there are complications that can arise during treatment, which increase the mortality rate significantly. For many of these complications, there is a limited understanding of the causes, making it challenging to propose and find solutions. When patients are treated using ECMO, the angle of insertion of the cannula will vary on a case-by-case basis. This will impact the flow from, and around, the cannula, and thus finding an optimal angle could minimise the turbulence in the flow, and therefore reduce the occurrence of complications, such as blood clots. Additionally, the datasheets for the cannulae used in clinical settings only provide measurements of water flow through the cannula, in coarse units of L/min. The aim of this project is to investigate the blood flow in such a system with higher precision, and in turn, provide insight on potential causes of some of the common complications. To do this, experimental flow measurements through a cannula and model vascular system can be acquired using positron emission particle tracking (PEPT). PEPT is an imaging technique, pioneered at the University of Birmingham, that is used to track the motion of individual radioactively labelled tracer particles. The first run of experiments has been carried out while systematically varying both the angle of insertion of the cannula and the fluid used in the model system.In parallel to the experimental work, numerical simulations of the system using computational fluid dynamics (CFD) are being developed. These simulations will be compared to the experimental results, and subsequently used to test more complex systems. Initially, both the experimental and simulation data will be analysed using existing methods. Following this, work will be carried out to explore the potential benefits of incorporating topological methods into the reconstruction and analysis algorithms.