Cardiac Diffusion Imaging for Heart Transplant Surveillance

用于心脏移植监测的心脏弥散成像

• 批准号: 8650639
• 负责人: ROLAND BAMMER
• 金额: $ 20.06万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-15 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8650639
• 关键词: Abdomen; Acute; Acute Brain Injuries; Address; Algorithms; Allografting; American; Angiography; Arrhythmia; Biological; Biopsy; Blood flow; Brain; Cardiac; Cardiac Catheterization Procedures; Caring; Catheters; Chronic; Clinical; Complication; Contrast Media; Coronary Angiography; Coupled; Data; Development; Diffusion; Diffusion Magnetic Resonance Imaging; Diffusion weighted imaging; Early Diagnosis; Early treatment; Echo-Planar Imaging; Echocardiography; Future; Goals; Gold; Graft Rejection; Heart; Heart Transplantation; Heart failure; Image; Imaging Techniques; Injury; Kidney Failure; Left ventricular structure; Life; Magnetic Resonance Imaging; Maps; Measures; Methods; Molecular; Monitor; Morbidity - disease rate; Motion; Myocardial; Myocardial perfusion; Myocardial tissue; Myocardium; North America; Patients; Perforation; Perfusion; Physiological; Population; Process; Property; Protocols documentation; Protons; Reference Standards; Regional Perfusion; Research; Resolution; Resources; Risk; Role; Sampling; Signal Transduction; Site; Solutions; Stroke; Symptoms; Techniques; Testing; Time; Tissues; Transplant Recipients; Validation; Variant; Vascular Diseases; Ventricular septum; Vertebral column; Water; Weight; Work; allograft rejection; base; cardiovascular imaging; cost; flexibility; healthy volunteer; heart allograft; heart motion; improved; in vivo; innovation; novel; outcome forecast; prevent; public health relevance; reconstruction; tool; user-friendly; volunteer

PROJECT SUMMARY / ABSTRACT Diffusion weighted imaging (DWI) has an established role in detecting acute brain injury, most notably in the early detection of stroke. The application of cardiac diffusion- weighted MRI (cDWI) is similarly relevant for non-invasive assessment of myocardial injury; however, in vivo cDWI remains a major technical challenge since bulk and pulsatile motion of the beating heart make resolving molecular diffusion much more problematic than it is in the brain. A promising application for cDWI is in heart transplantation for surveillance of allograft rejection. Heart transplant (HT) patients undergo routine monthly endomyocardial biopsies (EMB) in the first year and annual intra-arterial coronary angiography (ICA) to monitor for acute and chronic rejection, respectively. These tests are invasive and carry risks of valve damage, renal failure and cardiac perforation. Additionally, this surveillance practice is resource-demanding, adding to the enormous cost of HT. For over 25,000 Americans living with HT, a non-invasive method of graft surveillance - allowing for safe deferral of costly and invasive tests - is highly desirable. The goal of this project is to develop a robust cDWI technique for clinical use, with initial validation in HT patients for non-invasive surveillance of acute and chronic rejection. We propose to overcome the current limitations of cDWI using a short-axis propeller echo-planar imaging (SAP- EPI) MR sequence. By combining the ultra-fast EPI technique with a novel SAP motion-correction algorithm, the challenge of physiologic motion will be addressed while minimizing image distortion of standard EPI; additionally, this acquisition method is inherently flexible and can be reconstructed for high-resolution and time- resolved cardiac imaging. Aim 1 is sub-divided into technical (1A) and clinical (1B) goals: Aim 1A is focused on cDWI sequence development and retrospective correction of motion- induced cardiac errors and signal loss. SAP motion- correction will be developed to deal with the physiologic motion of the beating heart. Aim 1B will explore if cDWI can detect acute myocardial damage in the setting of acute cellular rejection (ACR) in HT patients. cDWI data in HT patients with and without ACR determined by gold standard EMB will be compared. Aim 2 is also sub-divided into technical (2A) and clinical (2B) goals: Aim 2A is focused on an advanced technical development of our cDWI sequence from Aim 1, modified for intravoxel incoherent motion (IVIM) with the goal of developing semi-quantitative perfusion imaging which can be performed without a contrast agent. Aim 2B will explore if cDWI IVIM perfusion imaging detects altered blood flow in HT patients with cardiac allograft vasculopathy (CAV). Perfusion fractions will be measured in patients with and without evidence of CAV determined by the gold standard ICA. The end-point of the clinical aims is to validate cDWI in the HT population and achieve a general proof of concept that myocardial characterization with cDWI is an achievable and accurate clinical tool. Our results may provide a threshold of altered diffusion/perfusion with cDWI and IVIM that will predict a positive EMB/ICA result - with safe deferral of costly and invasive tests in HT patients below this threshold. In Summary, this proposal aims at creating a new, clinically feasible cDWI sequence which addresses the unresolved issues of physiologic cardiac motion, which has until now prevented development and clinical use of cDWI for cardiac tissue characterization. Developing a robust cDWI sequence may change the existing management paradigm of HT patients by providing a completely non-invasive and risk-free method of allograft surveillance. Ultimately, we expect that the availability of routine cDWI will unlock the potentially game-changing role which cDWI may also have for non-invasive assessment, of myocardial injury abnormal myocardial perfusion in the future.

项目摘要 /摘要 扩散加权成像（DWI）具有确定的作用 在检测急性脑损伤时，最著名的是在早期 检测中风。心脏扩散的应用 - 加权MRI（CDWI）与非侵入性相似 评估心肌损伤；但是，体内CDWI 自批量和 跳动心的脉动运动使得解决 分子扩散比在 大脑。 CDWI的有希望的申请是内心 移植同种异体移植排斥的移植。 心脏移植（HT）患者每月进行常规 第一年的心内膜活检（EMB） 年度动脉内冠状动脉造影（ICA） 分别监测急性和慢性排斥。 这些测试是侵入性的，并承受阀门损坏的风险， 肾衰竭和心脏穿孔。另外，这个 监视实践是资源要求的，加上 HT的巨大成本。超过25,000名美国人 与HT一起生活，一种非侵入性移植方法 监视 - 允许安全延期昂贵，并且 侵入性测试 - 非常可取。 该项目的目的是开发强大的CDWI 临床使用技术，在HT中进行初始验证 急性监测的患者和 慢性拒绝。 我们建议克服CDWI的当前局限性 使用短轴螺旋桨回声 - 平面成像（SAP- EPI）MR序列。通过组合超快速EPI 具有新颖的SAP运动校正算法的技术， 生理运动的挑战将被解决 同时最大程度地减少标准EPI的图像失真； 此外，这种采集方法本质上是灵活的 并可以重建高分辨率和时间 - 解决心脏成像。 AIM 1分为技术（1A）和临床（1B） 目标：AIM 1A专注于CDWI序列 运动的发展和回顾性校正 - 引起心脏误差和信号损失。 SAP运动 - 将开发纠正以处理生理 跳动心的运动。 AIM 1B将探索CDWI是否 可以在情况下检测到急性心肌损伤 HT患者的急性细胞排斥（ACR）。 CDWI数据 在HT患者中有或没有ACR的HT患者中 将比较标准EMB。 AIM 2还分为技术（2a）和临床 （2b）目标：AIM 2A专注于高级技术 从AIM 1开发CDWI序列，修改 用于弹内的不一致运动（IVIM）的目标 开发半定量灌注成像，可以 在没有对比剂的情况下执行。 AIM 2B会 探索CDWI IVIM灌注成像是否检测到改变 HT同种异体移植患者的血流 Vasculopathy（CAV）。灌注部分将是 在有和没有CAV证据的患者中测量 由金标准ICA确定。 临床目的的终点是验证CDWI 在HT人群中，并获得了一般证明 CDWI的心肌表征是 可实现且准确的临床工具。我们的结果 可以提供改变扩散/灌注的阈值 CDWI和IVIM将预测阳性的EMB/ICA结果 - 在HT中安全延期昂贵和侵入性测试 低于此阈值的患者。 总而言之，该建议旨在创建一个新的 临床上可行的CDWI序列，以解决 未解决的生理心运动问题， 到目前为止，必须阻止开发和临床使用 CDWI用于心脏组织表征。开发 强大的CDWI序列可能会改变现有的 HT患者的管理范式通过提供 完全无创和无风险的同种异体移植方法 监视。最终，我们期望 常规CDWI将解锁可能改变游戏的可能性 CDWI也可能对非侵入性发挥作用 评估心肌损伤异常心肌心肌 未来的灌注。