4D flow cardiovascular magnetic resonance for monitoring of aortic valve repair in bicuspid aortic valve disease

Abstract

Background: Aortic valve repair has become a treatment option for adults with symptomatic bicuspid (BAV) or unicuspid (UAV) aortic valve insufficiency. Our aim was to demonstrate the feasibility of 4D flow cardiovascular magnetic resonance (CMR) to assess the impact of aortic valve repair on changes in blood flow dynamics in patients with symptomatic BAV or UAV. Methods: Twenty patients with adult congenital heart disease (median 35 years, range 18-64; 16 male) and symptomatic aortic valve regurgitation (15 BAV, 5 UAV) were prospectively studied. All patients underwent 4D flow CMR before and after aortic valve repair. Aortic valve regurgitant fraction and systolic peak velocity were estimated. The degree of helical and vortical flow was evaluated according to a 3-point scale. Relative flow displacement and wall shear stress (WSS) were quantified at predefined levels in the thoracic aorta. Results: All patients underwent successful aortic valve repair with a significant reduction of aortic valve regurgitation (16.7 ± 9.8% to 6.4 ± 4.4%, p < 0.001) and systolic peak velocity (2.3 ± 0.9 to 1.9 ± 0.4 m/s, p = 0.014). Both helical flow (1.6 ± 0.6 vs. 0.9 ± 0.5, p < 0.001) and vortical flow (1.2 ± 0.8 vs. 0.5 ± 0.6, p = 0.002) as well as both flow displacement (0.3 ± 0.1 vs. 0.25 ± 0.1, p = 0.031) and WSS (0.8 ± 0.2 N/m 2 vs. 0.5 ± 0.2 N/m 2 , p < 0.001) in the ascending aorta were significantly reduced after aortic valve repair. Conclusions: 4D flow CMR allows assessment of the impact of aortic valve repair on changes in blood flow dynamics in patients with bicuspid aortic valve disease.

Reliability of non-contrast magnetic resonance angiography-derived aortic diameters in Marfan patients: comparison of inner vs. outer vessel wall measurements

“…Four-dimensional phase contrast magnetic resonance imaging (4D flow MRI) is an advanced imaging technique, which allows for acquisition of morphological images and velocity data. 4D flow MRI thus enables visualization and quantification of complex blood flow patterns in the thoracic aorta [ 12 , 13 ]. Recent 4D flow MRI studies showed promising results in Marfan patients supporting the notion that pathological blood flow profiles may contribute to aneurysm formation [ 14 , 15 ].…”

Fetal dynamic magnetic resonance imaging using Doppler ultrasound gating for the assessment of the aortic isthmus: A feasibility study

“…The 4D flow MRI visualizes complex hemodynamic changes, eg vortices and helices, or eccentric flow. 24,25 Particularly with respect to the fetus, 4D flow MRI has several advantages over 2D phase-contrast MRI and echocardiography as it enables retrospective definition of the relevant target vessels within the acquired 3D volume with operator-independent offline analysis. Our initial results indicate that fetal aortic DUS-gated 4D flow MRI is feasible for the assessment of aortic hemodynamics including the aortic isthmus, revealing physiological flow patterns in our three healthy fetuses.…”

“…Four‐dimensional flow MRI is an emerging technique that allows time‐resolved co‐registration of both morphological and hemodynamic information in a 3D volume over the whole cardiac cycle. The 4D flow MRI visualizes complex hemodynamic changes, eg vortices and helices, or eccentric flow 24,25 . Particularly with respect to the fetus, 4D flow MRI has several advantages over 2D phase‐contrast MRI and echocardiography as it enables retrospective definition of the relevant target vessels within the acquired 3D volume with operator‐independent offline analysis.…”

Abdominal Applications of 4D Flow MRI

“…WSS estimates are influenced by the exact placement of the region of interest and by the chosen spatial resolution [62]. However, the relative intra-and interindividual distribution of WSS estimates might be reasonably accurate [5,35]. In the abdominal aorta, elevated WSS was described adjacent to the ostia of the renal arteries in healthy volunteers [63].…”

“…Four-dimensional flow magnetic resonance imaging (4D flow MRI) is a three-dimensional and time-resolved phase contrast imaging technique allowing characterization of blood flows within the entire vasculature [1][2][3]. 4D flow MRI enables the visualization of physiological and pathological flow patterns by registration of both morphology and velocity data [3][4][5].…”