Comprehensive quantitative magnetic resonance imaging in assessment of aortic valve disease

项目摘要/摘要 无症状的主动脉瓣狭窄(AS)患者有很高的死亡风险。治疗方式： 主动脉瓣置换术(AVR)是一种有效的治疗方法，但需要及时确定合适的 条件。目前确定症状状态的方法是高度主观的，而且经常无法 在不可逆转的心脏损伤发生前进行干预。同样，让无症状的高危患者 不治疗还可能导致他们发展为AS的不良心肌后遗症。心脏功能的评价 心脏形态、整体和局部心功能、主动脉顺应性以及心肌组织 成分将提供对AS患者心脏健康的全面评估 追踪慢性持续的主动脉瓣压力超负荷所导致的左室重构。 在这个项目中，我们建议开发三类磁共振成像(Mri)方法。 以便全面、定量地提供对心脏健康的理想评估。它们是：1)3D 电影MRI用于结构和功能评估；2)4D Flow MRI用于心肌局部功能和血液 血流评估；以及3)用于组织表征的3D定量参数标测，检测心肌 纤维化症。它们是高度加速的自由呼吸全心脏和主动脉成像技术，这些技术是 非常适合这种脆弱的患者群体，他们需要快速获得、自由呼吸策略，而不是 造影剂给药要求。 从定量MRI测量的左室射血分数(LVEF)、左室肥厚、 左心室舒缩功能不全、心肌纤维化、主动脉僵硬和扩张性及其相关性 将对症状的严重性进行分析，并将预测症状进展的最佳生物标志物 已确认身份。 这一全面的定量MRI方案用于评估心肌组织成分和 功能，重度主动脉瓣狭窄患者的主动脉异常将更准确地评估 砷的影响。更准确地说，定量磁共振参数可能有助于预测症状的发展和 重症主动脉狭窄患者症状严重程度的进展和改善当前患者的选择 主动脉瓣置换术的策略。该项目的成功将对医疗保健产生强大的影响 考虑到严重主动脉狭窄的临床重要性，以及现有方法无法可靠地 预测症状的发展或进展。

PROJECT SUMMARY/ABSTRACT Patients with asymptomatic aortic valve stenosis (AS) patients have a high mortality risk. Treatment by aortic valve replacement (AVR) is an effective therapy but requires timely identification of the appropriate condition. The current approach for determining symptomatic status is highly subjective and often fails to indicate intervention before irreversible cardiac damage occurs. Similarly, leaving at-risk asymptomatic patients untreated may also result in their developing the adverse myocardial sequellae of AS. Evaluation of cardiac ventricular morphology, global and regional cardiac function, aortic compliance, as well as myocardial tissue composition would provide a comprehensive assessment of the heart health in patients with AS that could track the remodeling of the LV as a result of chronic sustained aortic valve pressure overload. In this project, we propose to develop three categories of magnetic resonance imaging (MRI) approaches for comprehensively and quantitatively providing the desired evaluation on the heart health. They are: 1) 3D CINE MRI for structural and functional evaluation; 2) 4D flow MRI for myocardial regional function and blood flow assessment; and 3) 3D quantitative parametric mapping for tissue characterization, detecting myocardial fibrosis. They are highly accelerated free-breathing whole heart and aorta imaging techniques, which are well suitable for this fragile AS patient population who needs rapid acquisition, free breathing strategies, and no requirement of contrast administration. From the quantitative MRI measurements such as left ventricular ejection fraction (LVEF), LV hypertrophy, LV diastolic and systolic dysfunction, myocardial fibrosis, and aortic stiffness and distensibility, their association with severity of symptoms will be analyzed and best biomarkers for predicting symptomatic progression will be identified. This comprehensive quantitative MRI protocol for evaluation of myocardial tissue composition and function, and aortic abnormalities in patients with severe aortic valve stenosis will more accurately assess the effects of AS. More precisely, quantitative MR parameters may help predict development of symptoms and progression of symptom severity in patients with critical aortic stenosis, and improve current patient selection strategies for aortic valve replacement. Success of this project will have a strong impact on the health care system given the clinical importance of severe aortic stenosis, and the inability of current methods to reliably predict the development or progression of symptoms.