SEMANTIC CLASSIFICATION OF PICTURES & WORDS: FMRI OF REPETITION PRIMING: MEMORY

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• 批准号: 6123031
• 负责人: EUJOON KANG
• 金额: $ 0.07万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6123031
• 关键词: bioimaging /biomedical imaging; biomedical resource; magnetic resonance imaging; mother /infant health care; radiology; urinary tract

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.

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) 鼻咽癌的临床处理和手术计划技术 肾功能恶化的儿科患者。这个 长期目标是取代现有的肾脏检查，这涉及到 给患者带来了巨大的成本和风险， 具有成本效益的非侵入性检查。方法：1)建立大鼠脑缺血模型。 肾脏的发展是为了预测造影剂的速度 近端肾小管较晚，降环较细。假设 滤液的初始速度直接与 压力(渗透压和静压)之间的梯度 肾小球和初始近端曲管的血流速度 原则上，可以外推肾单位的不同部分，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，其目标将是预测这些 在已知肾小球和肾小球的先验知识的情况下，相关的压力梯度 收集系统压力、流体粘度、扩散常数和 小管几何图形(面积和长度)。2)肾脏的模型可能是 开发的目的是为了确定Gd-DTPA的绝对浓度。 这将直接衡量区域集聚能力。 类似于目前使用的核医学研究。 由于对于给定序列(例如，GRASS)，信号强度是 复杂函数T1、T2、T2*和Gd-DTPA浓度，多 必须考虑这些因素。结论：在接下来的一年里 将比较交错螺旋、短TRGRE、单次激发EPI脉冲 序列在空间分辨率、时间分辨率和 对不均匀和运动的敏感性。的终极选择 动态MRI脉冲序列也将受到最小值的约束 可视化肾脏所需的时间和空间分辨率要求 病理学。数据分析和图像处理算法将 重点关注相关成像等技术，这些技术强调 检测和可视化区域性肾缺陷，而不是 肾功能的绝对定量。