Imaging assessment of a portable hemodialysis device: detection of possible failure modes and monitoring of functional performance.
Imaging assessment of a portable hemodialysis device: detection of possible failure modes and monitoring of functional performance.
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DOI：
10.7243/2052-6962-2-2
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发表时间：
2014-03-27
期刊：
影响因子：
--
通讯作者：
Wilson MW
中科院分区：
文献类型：
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作者：
Olorunsola OG;Kim SH;Chang R;Kuo YC;Hetts SW;Heller A;Kant R;Saeed M;Fissell WH;Roy S;Wilson MW
本研究的目的是研究各种成像方式在肾脏替代治疗中开发的新型紧凑型血液透析器的无创评估中的实用性和局限性，具体目的是监测其功能性能。原型是一个4×3×6 cm的铝制药筒，内有平行排列的“血液”和“透析液”流路。一片半渗透性硅纳米孔膜形成血液-透析液界面，允许小分子通过。使用蠕动泵模拟血流，通过血液室滴注碘化造影剂，同时以逆流方向以匹配的速率通过透析液室滴注去离子水。在这些血流条件下使用多探测器计算机断层扫描（MDCT）、荧光透视、高分辨率定量计算机断层扫描（HR-QCT）和磁共振成像（MRI）采集图像。MDCT用于监测造影剂扩散效率，方法是在1 mL/min和20 mL/min的稳态输注过程中，将造影剂密度作为沿着通过药筒的流动路径的位置的函数进行绘图。线性和指数回归均用于模拟沿着流动路径的造影剂衰减。造影剂衰减的线性和指数模型似乎都是合理的近似值，在单次通过药筒期间产生类似的对比扩散结果。当比较1 mL/min和20 mL/min流速时，造影剂扩散没有可测量的差异。荧光透视允许对器械内的流量进行大体定性评估，并显示血液入口对面的测试卡片角落内的流量不均匀性。MRI和HR-QCT分别由于靶材料的顺磁性和高原子序数而受到严重限制。在测试过程中，我们遇到了设备故障的几个原因，包括泄漏形成、截留气体和造影剂介导的纳米孔堵塞。我们举例说明每一种的影像学表现。尽管主要金属器械的成像存在固有挑战，但某些模式在新型紧凑型血液透析器的无创评估中显示出潜力。本文描述的方法可能转化为植入环境中的器械评价。
The purpose of this study was to investigate the utility and limitations of various imaging modalities in the noninvasive assessment of a novel compact hemodialyzer under development for renal replacement therapy, with specific aim towards monitoring its functional performance. The prototype is a 4×3×6 cm aluminum cartridge housing “blood” and “dialysate” flow paths arranged in parallel. A sheet of semipermeable silicon nanopore membranes forms the blood-dialysate interface, allowing passage of small molecules. Blood flow was simulated using a peristaltic pump to instill iodinated contrast through the blood compartment, while de-ionized water was instilled through the dialysate compartment at a matched rate in the countercurrent direction. Images were acquired under these flow conditions using multi-detector computed tomography (MDCT), fluoroscopy, high-resolution quantitative computed tomography (HR-QCT), and magnetic resonance imaging (MRI). MDCT was used to monitor contrast diffusion efficiency by plotting contrast density as a function of position along the path of flow through the cartridge during steady state infusion at 1 and 20 mL/min. Both linear and exponential regressions were used to model contrast decay along the flow path. Both linear and exponential models of contrast decay appeared to be reasonable approximations, yielding similar results for contrast diffusion during a single pass through the cartridge. There was no measurable difference in contrast diffusion when comparing 1 mL/min and 20 mL/min flow rates. Fluoroscopy allowed a gross qualitative assessment of flow within the device, and revealed flow inhomogeneity within the corner of the cartridge opposite the blood inlet port. MRI and HR-QCT were both severely limited due to the paramagnetic properties and high atomic number of the target material, respectively. During testing, we encountered several causes of device malfunction, including leak formation, trapped gas, and contrast-mediated nanopore clogging. We illustrate the imaging manifestations of each. Despite the inherent challenges in imaging a predominantly metallic device, some modalities show potential in the non-invasive assessment of a novel compact hemodialyzer. The approaches described here could potentially be translated to device evaluation in the implanted setting.