Dynamic MRI for Myocardial Perfusion and Viability

描述(由申请人提供)：这项建议旨在提高使用MRI表征缺血性心脏病的准确性和可重复性。前两个目标集中在动态MRI的血流灌注方面：(1)发展径向k空间采集方法，提供快速测量Gd浓度的方法，以提高对心肌绝对血流灌注的估计。(2)改进和自动化动态数据的后处理分析，以获得稳健的定量血流灌注估计值。将开发新的配准、分割和动力学建模方法，以自动生成绝对灌注图和置信度图。(3)用3Tesla磁共振确定新的灌注方法的准确性和可重复性。还将评估用于菌株和疤痕图谱的新方法的重复性。(4)将该方法应用于冠状动脉旁路移植术后接受骨髓干细胞治疗的患者的纵向研究。方法：将使用真实的计算机模拟、模体和人体研究来开发放射状灌注序列，以从高剂量动态MRI研究中提供准确的Gd浓度。将开发切片跟踪采集和组合配准/分割方法，以便对数据进行强有力的自动化处理。将开发不同的生理模型，并比较它们提供绝对灌注值的能力。将开发和测试通过联合估计组织和动脉输入功能模型拟合来改善输入功能的数学方法。新的径向切片跟踪采集和处理方法将在同一患者中通过与动态PET的定量灌注以及与笛卡尔采集的比较来验证。将在20名受试者中对灌流方法以及应变和疤痕映射技术的重复性进行表征，每个受试者都进行两次成像。然后，这些新方法将被应用于对干细胞治疗的心肌反应产生新的见解。该项目的成果将是用于心脏MRI研究的有效成像方案和软件，改进的心肌灌注、应变和体内疤痕的纵向评估方法，以及有关干细胞对心脏灌注、应变和疤痕影响的新信息。这些方法对于评估新的治疗方法以及检测和表征缺血性心脏病将是非常有价值的。

DESCRIPTION (provided by applicant): This proposal seeks to improve the accuracy and repeatability of the characterization of ischemic heart disease using MRI. The first two aims focus on dynamic MRI for perfusion: (1) To develop radial k-space acquisition methods to provide rapid measurements of gadolinium concentration to improve the estimation of absolute myocardial perfusion. (2) To improve and automate post-processing analysis of the dynamic data to obtain robust quantitative perfusion estimates. New methods for registration, segmentation, and kinetic modeling will be developed to automatically produce maps of absolute perfusion along with a confidence map. (3) To determine the accuracy and repeatability of the new perfusion methods using 3 Tesla MRI. The repeatability of new methods for strain and scar mapping will also be assessed. (4) To apply the methods to longitudinal studies of patients undergoing bone marrow stem cell therapy as an adjunct to coronary artery bypass grafting. Methods: Development of radial perfusion sequences to provide accurate gadolinium concentrations from high dose dynamic MRI studies will be pursued using realistic computer simulations, phantoms, and human studies. Slice tracking acquisitions and combined registration/segmentation methods will be developed for robust automated processing of the data. Different physiological models will be developed and compared in their ability to provide absolute perfusion values. Mathematical methods for improving input functions by jointly estimating tissue and arterial input function model fits will be developed and tested. The new radial slice-tracking acquisition and processing methods will be validated by comparison in the same patients to quantitative perfusion from dynamic PET, along with comparison to a Cartesian acquisition. The repeatability of the perfusion methods and the strain and scar mapping techniques will be characterized in 20 subjects, each imaged twice. The new methods will then be applied to generate new insights into the myocardial response to stem cell therapy. The outcome of this project will be validated imaging protocols and software for use with cardiac MRI studies, improved methods for longitudinal assessment of myocardial perfusion, strain, and scar in vivo, and new information regarding the effect of stem cells on cardiac perfusion, strain, and scar. Such methods will be invaluable for evaluating novel therapies and for the detection and characterization of ischemic heart disease.