Cardiac magnetic resonance systematically overestimates mitral regurgitations by the indirect method

Abstract

ObjectiveCardiac MRI is quickly emerging as the gold standard for assessment of mitral regurgitation, most commonly with the indirect method subtracting forward flow in aorta from volumetric segmentation of the left ventricle. We aimed to investigate how aortic flow measurements with increasing distance from the aortic valve affect calculated mitral regurgitations and whether measurements were influenced by breath-hold regimen.MethodsFree-breathing and breath-hold phase contrast flows were measured in aorta at valve level, sinotubular (ST) junction, mid-ascending aorta and in the pulmonary trunk. Flow measurements were pairwise compared, and subsequently, after exclusion of patients with visible mitral and tricuspid regurgitations for left-sided and right-sided comparisons, respectively, flow-measured stroke volumes were compared with ventricular volumetric segmentations.ResultsThirty-nine participants without arrhythmias or structural abnormalities of the large vessels were included. Stroke volumes measured with free-breathing and breath-hold flow decreased equally with increasing distance to the aortic valves (breath-hold flow: aortic valve 105.6±20.8 mL, ST junction 101.5±20.7 mL, mid-ascending aorta 98.1±21.5 mL). After exclusion of atrioventricular regurgitations, stroke volumes determined by volumetric measurements were higher compared with values determined by flow measurements, corresponding to ‘false’ atrioventricular regurgitations of 8.0%±5.8% with flow measured at valve level, 11.6%±5.2% at the ST junction and 15.3%±5.0% at the mid-ascending aorta.ConclusionsStroke volumes determined by flow decrease throughout the proximal aorta and are systematically lower than volumetrically measured stroke volumes. The indirect method systematically overestimates mitral regurgitations, especially with increasing distance from the aortic valves.

Reduced External Iliac Venous Blood Flow Rate Is Associated with Asymptomatic Compression of the Common Iliac Veins

“…In our hospital, we have used the QFlow technique to measure pelvic and lower limb venous blood flow. Although this application is rarely encountered, it should be applicable because, even though QFlow usually underestimates the blood flow velocity when blood flow is turbulent and when a vessel diameter is small [ 30 , 31 , 32 , 33 , 34 ], the iliac veins and FVs are usually large, and their blood flow usually presents as laminar flow; therefore, related blood flow measurements are generally accurate. Combining TRANCE MRI and QFlow provides a safe and convenient diagnostic tool for surveying and following up on lower limb venous disease.…”

Role of Cardiovascular Magnetic Resonance in Native Valvular Regurgitation: A Comprehensive Review of Protocols, Grading of Severity, and Prediction of Valve Surgery

“…The LVSV can be obtained from multiple LV short-axis cine bSSFP images, and the AFF from phase-contrast velocity flow in a trough-plane acquired at the level of the sinotubular junction or the aortic valve but not at the mid-ascending aorta due to the risk of overestimation ( 18 ). This sequence generates two types of images: a magnitude image showing the anatomy of the aortic valve and a phase map encoding the velocities within each voxel.…”

Comparative Study of 2D-Cine and 3D-wh Volumetry: Revealing Systemic Error of 2D-Cine Volumetry

“…In the past, various reasons have been discussed as triggers. In particular, the lack of inclusion of the papillary muscles [16] and the masking of mitral valve insufficiency were suspected as influencing factors [17].…”