DYNAMIC MAGNETIC RESONANCE IMAGING OF PEDIATRIC KIDNEY

简介：这是一个跨学科的生物工程项目 开发和评估动态磁共振成像（MRI） 临床管理和手术计划的技术 患有肾功能恶化的儿科患者。 的 长期目标是取代现有的肾脏检查， 对患者的重大成本和风险，全面， 成本效益高的非侵入性检查。 方法：1）建立了一个 肾脏的发展，以预测速度的造影剂在 晚期近端小管和Henle氏细降袢。 假设 滤液的初始速度与 之间的压力（渗透压和流体静力学）梯度 肾小球和初始近曲小管，速度在 原则上，如果 相关的空间相关压力是已知的。 使用集总 参数元素设计理论，目标将是预测这些 考虑到肾小球的先验知识， 收集系统压力、流体粘度、扩散常数，以及 小管几何形状（面积和长度）。 2)肾脏的模型可以是 开发，以便绝对Gd-DTPA浓度可以确定。 这将直接衡量区域集中能力 类似于目前使用的核医学研究。 因为，对于给定的序列（例如，GRASS），信号强度为 复杂的函数T1、T2、T2* 和Gd-DTPA浓度， 必须考虑各种因素。 结论：明年，我们 将比较交错螺旋、短TR GRE、单次激发EPI脉冲 空间分辨率、时间分辨率和 对不均匀性和运动的敏感性。 的必然选择 动态MRI脉冲序列也将受到最小 可视化肾脏所需的时间和空间分辨率要求 病理 数据分析和图像处理算法将 重点关注相关成像等技术， 检测和可视化局部肾缺陷，而不是 肾功能的绝对定量。

Introduction: This is an interdisciplinary bioengineering project to develop and evaluate dynamic magnetic resonance imaging (MRI) techniques for the clinical management and surgical planning of pediatric patients suffering from deteriorating renal function. The long term goal is to replace the existing renal tests, which involve significant costs and risks to patients, with a comprehensive, cost-effective, noninvasive examination. Methods: 1) A model of the kidney developed to predict the velocity of the contrast media in the late proximal tubule and thin descending loop of Henle. Assuming that the initial velocity of the filtrate is directly related to the pressure (both osmotic and hydrostatic) gradients between the glomerulus and the initial proximal convoluted tubule, velocities in different parts of the nephron can be extrapolated, in principle, if the relevant spatially dependent pressures are known. Using lumped parameter element design theory, the goal would be to predict these relevant pressure gradients given a priori knowledge of glomerulus and collecting system pressures, fluid viscosity, diffusion constants, and tubule geometry (area and length). 2) A model of the kidney may be developed so that absolute Gd-DTPA concentrations can be ascertained. This would give a direct measure of regional concentrating ability similar to the nuclear medicine studies that are currently used. Since, for a given sequence (e.g., GRASS), the signal intensity is a complicated function T1, T2, T2* and Gd-DTPA concentration, many factors must be considered. Conclusions: During the next year we will compare interleaved spiral, short-TR GRE, single-shot EPI pulse sequences in terms of spatial resolution, temporal resolution, and sensitivity to inhomogeneities and motion. The ultimate choice of dynamic MRI pulse sequence will also be constrained by the minimum temporal and spatial resolution requirements needed to visualize renal pathology. The data analysis and image processing algorithms will focus on techniques such as correlation imaging that emphasize the detection and visualization of regional renal defects rather than absolute quantitation of kidney function.