4D Flow MRI in Assessment of True Severe Low-Gradient Aortic Stenosis

4D Flow MRI 评估真正的严重低梯度主动脉瓣狭窄

• 批准号: 10735953
• 负责人: AMIR A AMINI
• 金额: $ 23.48万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10735953
• 关键词: 3-Dimensional; 4D MRI; Adopted; Affect; Anatomy; Aortic Diseases; Aortic Valve Stenosis; Area; Breathing; Catheterization; Cessation of life; Chest; Chronic; Classification; Clinical; Correlation Studies; Data; Diagnostic; Diagnostic Procedure; Dobutamine; Dobutamine Stress Echocardiography; Doppler Echocardiography; Drops; Echocardiography; Enrollment; Equation; Goals; Heart; Heart Valve Diseases; Heart failure; Image; Learning; Left Ventricular Ejection Fraction; Liquid substance; Magnetic Resonance Imaging; Maps; Measurement; Measures; Methods; Modality; Morphologic artifacts; Nature; Noise; Operative Surgical Procedures; Patients; Protocols documentation; Rest; Risk; Safety; Scanning; Severities; Severity of illness; Stratification; Stress; Subgroup; Survival Rate; Symptoms; Syncope; Therapeutic Embolization; Training; Work; adverse outcome; aging population; anatomic imaging; aortic valve; aortic valve disorder; aortic valve replacement; data space; deep learning; hemodynamics; human subject; imaging modality; improved; pressure; respiratory; simulation; tomography; ultrasound

Degenerative aortic stenosis is a progressive valvular heart disease affecting the aging population and when hemodynamically significant is associated with serious adverse outcomes, such as heart failure, syncope, and death. Although, symptomatic classical severe aortic stenosis (AS), wherein aortic valve anatomical or effective area is ≤ 1.0 𝑐𝑚2 and mean gradient ≥ 40 mmHg raises no diagnostic dilemma, patients with low gradient aortic stenosis (i.e., mean gradient < 40 mmHg) that may be severe (i.e., aortic valve area ≤ 1.0 𝑐𝑚2) remain a challenge for determining the true severity of aortic stenosis and present a significant unmet clinical need. The discordance between aortic valve area of ≤ 1.0 𝑐𝑚2 and mean gradient < 40 mmHg is encountered in as many as 30 to 40% of patients with aortic valve area ≤ 1.0 𝑐𝑚2 by transthoracic echocardiography (TTE). In patients with these discordant findings, the true severity is uncertain and have led to the use of dobutamine stress echocardiography (DSE). Based on DSE, one can classify the potentially severe low-gradient subjects into 4 distinct subgroups a) Low gradient severe aortic stenosis (LGS): aortic valve area of ≤ 1.0 𝑐𝑚2 and a mean gradient of ≥ 40 mmHg with DSE. b) Low gradient pseudo-severe aortic stenosis (LGPS): aortic valve area of > 1.0 𝑐𝑚2 and a mean gradient of < 40 mmHg with DSE. c) Low gradient indeterminate aortic stenosis severity (LGI): aortic valve area of ≤ 1.0 𝑐𝑚2 and a mean gradient of < 40 mmHg with DSE. d) Finally, aortic valve area of > 1.0 𝑐𝑚2 and a mean gradient of ≥ 40 mmHg with DSE are classified as moderate or less severe aortic stenosis (LSA). Nearly one-third of patients classified as LGS are classified as LGPS with DSE (6). Further, compounding the concern in patients classified as LGPS, LGI, LSA is that they often manifest with symptoms potentially attributable to severe AS suggesting an initial misclassification perhaps due to measurement errors. Compared to echo, with MRI, the velocities can be measured in all 3D directions and due to its tomographic nature, no geometric assumptions are required. The hypothesis of the study is that our planned CMR methods which we will develop based on previous work will be able to better stratify these AS subjects. Our specific aims are: 1) We will develop efficient rest and dobutamine stress 4D Spiral flow imaging protocols based on k-space dependent respiratory gating. 2) We have recently developed a Deep Learning framework which based on Computational Fluid Dynamics (CFD) simulations of training data learns to directly map velocities to pressures. This will be adapted to measure the transvalvular pressure gradients (TVPG) in human subjects and validated. 3) In 40 subjects with potentially severe low gradient AS (10 in each of the LGS, LGPS, LGI, LSA), a TTE study, and a CMR study will be performed both at rest and under dobutamine stress. To validate, TVPG will be measured with cath in a group with n=10 of moderate AS (MAS) subjects undergoing cath for other purposes. This group will also undergo TTE and CMR studies. Subjects with severe AS were not selected for cath for safety reasons. Classification across modalities, flow, velocity, pressure, and orifice area will be statistically correlated.

退行性主动脉瓣狭窄是一种进行性心脏瓣膜病，多发于老年人群和发病时间

项目成果

4Dflow-VP-Net: A deep convolutional neural network for noninvasive estimation of relative pressures in stenotic flows from 4D flow MRI.

• DOI: 10.1002/mrm.29791
• 发表时间: 2023-11
• 期刊: MAGNETIC RESONANCE IN MEDICINE
• 影响因子: 3.3
• 作者: Nath, Ruponti;Kazemi, Amirkhosro;Callahan, Sean;Stoddard, Marcus F.;Amini, Amir A.
• 通讯作者: Amini, Amir A.