Feasibility and validation of trans-valvular flow derived by four-dimensional flow cardiovascular magnetic resonance imaging in patients with atrial fibrillation

Abstract

Background: Four-dimensional (4D) flow cardiovascular magnetic resonance imaging (MRI) is an emerging technique used for intra-cardiac blood flow assessment. The role of 4D flow cardiovascular MRI in the assessment of trans-valvular flow in patients with atrial fibrillation (AF) has not previously been assessed. The purpose of this study was to assess the feasibility, image quality, and internal validity of 4D flow cardiovascular MRI in the quantification of trans-valvular flow in patients with AF. Methods: Patients with AF and healthy controls in sinus rhythm underwent cardiovascular MRI, including 4D flow studies. Quality assurance checks were done on the raw data and streamlines. Consistency was investigated by trans-valvular flow assessment between the mitral valve (MV) and the aortic valve (AV). Results: Eight patients with AF (88% male, mean age 62±13 years, mean heart rate (HR) 83±16 beats per minute (bpm)) were included and compared with ten healthy controls (70% male, mean age 41±20 years, mean HR 68.5±9 bpm). All scans were of either good quality with minimal blurring artefacts, or excellent quality with no artefacts. No significant bias was observed between the AV and MV stroke volumes in either healthy controls (–4.8, 95% CI –15.64 to 6.04; P=0.34) or in patients with AF (1.64, 95% CI –4.7 to 7.94; P=0.56). A significant correlation was demonstrated between MV and AV stroke volumes in both healthy controls (r=0.87, 95% CI 0.52 to 0.97; P=0.001) and in AF patients (r=0.82, 95% CI 0.26 to 0.97; P=0.01). Conclusions: In patients with AF, 4D flow cardiovascular MRI is feasible with good image quality, allowing for quantification of trans-valvular flow.

Validation of time-resolved, automated peak trans-mitral velocity tracking: Two center four-dimensional flow cardiovascular magnetic resonance study

“…Automated retrospective valve-tracking on long-axis four-chamber orthogonal cine views was carried out using CAAS MR software during image post-processing. This was performed using recently published and well-established methods (15)(16)(17) (Figure 1 and 2). After manual correction of any misalignment between the 4D flow CMR data and the cine images, automated tracking of mitral inflow allowed for careful isolation of transvalvular forward flow through only the mitral valve and into the left ventricle during diastole.…”

4D Flow cardiovascular magnetic resonance consensus statement: 2023 update

“…Retrospective valve tracking can be applied in patients with atrial fibrillation [ 76 ]. However, a cautious approach should be used as there is a possibility of underestimating flows.…”

Rationale and clinical applications of 4D flow cardiovascular magnetic resonance in assessment of valvular heart disease: a comprehensive review

“…Furthermore, as all the measurements are obtained from the same acquisition, the impact of variability related to changes in heart rate, on consistency of measurements will be reduced [ 28 ]. Although blurring can occur as a result of irregular heart rate [ 29 ], recent study showed that measurements of flow volumes remain accurate and feasible even in the presence of atrial fibrillation [ 30 ]. Moreover, peak velocity measurements in stenotic lesions may be more accurate and precise than with PCMR [ 31 ].…”