Quantitative cardiac MRI perfusion for longitudinal studies

描述(由申请人提供)：这项工作旨在开发、评估和使用新的MRI方法来无创性地定量评估心肌灌注储备(MPR)。这些方法将被设计成对心律失常或心电信号差的患者有效。这些方法将与左心室(LV)和左房(LA)功能一起应用 和LA纤维化测量，以研究房颤(AF)治疗后的变化。具体目标是(1)设计和测试高度欠采样的非门控血流灌注采集和重建。(2)通过改进处理和使用广泛适用于各种剂量和采集类型的方法识别准确的动脉输入功能，提供可靠的定量血流灌注估计。(3)确定所提出的定量方法的有效性和重复性，以及在收缩和舒张期测量的血流灌注和MPR的差异，包括确定在定量灌注量时，收缩或舒张期的重复性最好。(4)测定房颤消融治疗后血流储备、心功能和左房纤维化随时间的变化。这将使得能够准确地确定由于转为窦性心律而导致的血流灌注改善的程度，以及在几个月内恢复较慢的灌注储备的恢复程度。这些目标将通过开发在没有选通信号的情况下连续获取灌注数据的方法来实现。选通将通过回溯分析数据来完成。先进的重建方法，包括低等级和时空限制，以及使用呼吸和心脏运动补偿，将被开发和测试快速获得的自门控灌注序列。利用约束数据驱动的盲估计法可以得到准确的动脉输入函数。新方法的准确性将通过在房颤动物模型中的验证来确定，并通过与动态PET的人体研究进行比较来确定，并将表征方法的重复性。这些方法在接受消融治疗的患者中的系列应用将提供与心肌重塑相关的变化的新信息。这种准确和可重复的人体血流灌注测量的开发和使用将加速临床治疗的评估，并为心脏病患者的管理提供新的工具和知识。

DESCRIPTION (provided by applicant): This work seeks to develop, evaluate and use new MRI methods for non-invasive quantitative assessment of myocardial perfusion reserve (MPR). The methods will be designed to work robustly for patients with arrhythmias or poor ECG signals. The methods will be applied along with left ventricular (LV) and left atrial (LA) function and LA fibrosis measurements to study changes due to treatment for atrial fibrillation (AF). Specific aims are (1) To design and test highly-undersampled ungated perfusion acquisitions and reconstructions. (2) To provide robust quantitative perfusion estimates by improved processing and by identifying an accurate arterial input function using methods that are widely applicable across a range of doses and acquisition types. (3) To determine the validity and repeatability of the proposed quantitative methods and the differences in perfusion and MPR measured at systole and diastole, including determining if systole or diastole is most repeatable when quantifying perfusion. (4) To determine the changes over time in perfusion reserve and cardiac function and left atrial fibrosis, after ablative treatment for AF. This will allow for determining the extent of perfusion improvement acutely due to conversion to sinus rhythm and the degree of recovery of perfusion reserve that recovers more slowly over months. These aims will be accomplished by developing methods to acquire perfusion data continuously, without a gating signal. Gating will be accomplished by analyzing the data retrospectively. Advanced reconstruction methods that include low rank and spatiotemporal constraints, and that employ compensation for respiratory and cardiac motion, will be developed and tested with the rapidly acquired self-gated perfusion sequences. An accurate arterial input function will be obtained using constrained data- driven blind estimation techniques. The accuracy of the new methods will be determined by validation in an animal model of AF, and by comparison to human studies with dynamic PET, and the repeatability of the methods will be characterized. The serial application of the methods to patients undergoing ablation therapy will then provide new information regarding changes associated with myocardial remodeling. The development and use of such accurate and repeatable measurements of perfusion in humans will accelerate evaluation of clinical therapies, and provide new tools and knowledge for the management of patients with cardiac disease.