4D MRI Development for Cardiovascular Imaging

描述(由申请者提供)：冠状动脉疾病和心功能评估是心脏健康评估的关键要素。这项研究的目标是 开发4D磁共振成像(MRI)技术，提供无创和有效的心脏成像检查，包括评估冠状动脉疾病(CAD)和左(LV)和右(RV)功能。超声心动图(ECHO)被广泛用于评估功能，但仅限于解剖的2D视图。考虑到RV的位置、小梁和复杂的解剖结构，它测量RV尺寸的能力很差。CT血管造影术(CTA)提供了无创性的冠心病和心功能评估，但它涉及到电离辐射和碘化造影剂的肾毒性风险。适当的CTA通常需要使用β受体阻滞剂，并通过给予硝酸甘油来改善，这两种药物对某些患者都是禁忌。冠状动脉造影术(CA)是确定是否存在冠心病的权威研究，但它具有侵入性，按BOT美元计算代价高昂，并不能评估患者的心脏功能。心脏磁共振成像(MRI)提供了几种强大的功能。它是通过2D屏气电影采集来量化心功能的金标准。以舒张期中期为中心的全心冠状动脉MRA也在没有对比剂注射的情况下被证实。然而，这两种应用都受到心脏和呼吸运动带来的挑战的限制。2D MRI上的心功能定量受到呼吸不一致和随之而来的切片到切片空间配准错误的影响，特别是当患者，如肺移植候选人， 甚至不能进行短暂的屏气。不一致的呼吸和在舒张期中期选择固定的窗口会导致不可接受的扫描时间，并降低冠状动脉研究中的图像质量，因为那时一些冠状动脉节段并不是静止的。在这项研究中，我们的目标是：1)开发具有新的自门控、运动校正和先进的图像重建方法的自门自由呼吸4D心脏MRI；2)优化用于心功能成像和冠状动脉成像的4D MRI方案；3)将优化后的方法应用于心脏病患者的评估。拟议的4D心脏MRI的成功实施不仅对于评估CAD和心功能将是重要的，而且将推广到 需要类似能力的条件，如瓣膜疾病的评估、缺血心肌的增强成像和血管顺应性评估。这将为广大患有这些疾病的患者提供更好的护理，并为医疗保健系统带来经济利益。

DESCRIPTION (provided by applicant): Assessments of coronary artery disease and ventricular function are crucial elements for heart health evaluation. The goal of this research is to develop 4D magnetic resonance imaging (MRI) techniques that provide a non-invasive and effective cardiac imaging examination, including assessing coronary artery disease (CAD) and both left (LV) and right ventricular (RV) function. Echocardiography (ECHO) is widely used to assess function but is limited to 2D views of the anatomy. It has poor ability to measure RV dimensions given the position, trabeculations, and complex anatomy of the RV. CT angiography (CTA) provides non-invasive assessment of CAD and ventricular function, however it involves exposure to ionizing radiation and risk of nephrotoxicity from iodinated contrast agents. Adequate CTA generally requires the use of beta blockers and is improved by the administration of nitroglycerin, both of which are contraindicated for certain patients. Coronary angiography (CA) is the definitive study for identifying the presence of CAD, but it is invasive, costly in bot dollar terms and patient morbidity, and provides no assessment of ventricular function. Cardiac magnetic resonance imaging (MRI) offers several powerful capabilities. It is the gold standard for quantitating ventricular function with 2D breath-hold cine acquisitions. Whole-heart coronary MRA centered on mid-diastole has also been demonstrated without contrast injection. However, both applications are limited by the challenges posed by cardiac and breathing motion. Cardiac function quantitation on 2D MRI suffers from breathing inconsistencies and consequent slice-to-slice spatial misregistration, particularly when patients, such as lung transplantation candidates, are unable to perform even a short breath-hold. Inconsistent breathing and selection of a fixed window at mid-diastole results in unacceptable scan times and reduces image quality in coronary studies since some coronary segments are not quiescent at that time. In this research we aim to: 1) develop self-gated free-breathing 4D cardiac MRI with novel self-gating, motion correction, and advanced image reconstruction methods; 2) optimize a 4D MRI protocol for cardiac function imaging and coronary artery imaging; and 3) implement the optimized methods in assessment of cardiac patients. Successful implementation of the proposed 4D cardiac MRI will not only be important for assessing CAD and ventricular function, but will be generalizable to conditions requiring similar capabilities, such as evaluation of valve disease, enhanced imaging of ischemic myocardium and assessment of vascular compliance. This will offer improved care for the vast population of patients with these conditions and financial benefits for the health car system.