A Systematic Review of 4D-Flow MRI Derived Mitral Regurgitation Quantification Methods

Abstract

Background: Four-dimensional flow cardiac magnetic resonance (4D flow CMR) is an emerging non-invasive imaging technology that can be used to quantify mitral regurgitation (MR) volume. Current methods of quantification have demonstrated limitations in accurate analysis, particularly in difficult cases such as complex congenital heart disease. 4D flow CMR methods aim to circumvent these limitations and allow accurate quantification of MR volume even in complex cases. This systematic review aims to summarize the available literature on 4D flow CMR MR quantification methods and examine their ability to accurately classify MR severity. Methods: Structured searches were carried out on Medline and EMBASE in December 2018 to identify suitable research outcome studies. The titles and abstracts were screened for relevance, with a third adjudicator utilized when study suitability was uncertain. Results: Seven studies met the eligibility criteria and were included in the systematic review. The most widely used 4D flow MRI method was retrospective valve tracking (RVT) which was examined in five papers. The key finding of these papers was that RVT is a reliable and accurate method of regurgitant volume quantification. Conclusions: MR quantification through 4D flow MRI is both feasible and accurate. The evidence gathered suggests that for MR assessment, 4D flow MRI is potentially as accurate and reliable to echocardiography and may be complementary to this technique. Further work on MR quantification 4D flow image analysis is needed to determine the most accurate analysis technique and to demonstrate 4D flow MRI as a predictor of clinical outcome. PROSPERO Registration Number: CRD42019122837, http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42019122837

A review of the pivotal role of cardiac MRI in mitral valve regurgitation

“…15,24,25 CMR can also assess the impact of systolic variation on mitral cardiography. 46 In one retrospective study, as compared to multiplanar standard techniques for CMR, 4D flow methods had excellent correlation with high inter-and intra-observer reliability. 47…”

“…A systematic review of seven studies with 4D flow‐derived methods for MR quantification demonstrates increased accuracy and reliability in direct measurement when compared to standard CMR techniques and establishes a complementary role with echocardiography. 46 In one retrospective study, as compared to multiplanar standard techniques for CMR, 4D flow methods had excellent correlation with high inter‐ and intra‐observer reliability. 47 …”

The mitral regurgitation effects of cardiac structure and function in left ventricular noncompaction

“…These patients should receive more attention in clinical disease management and treatment. However, according to the current guidelines for evaluating the degree of mitral regurgitation, there is a lack of true gold standard, which method quantifies MR severity with the highest degree of accuracy and reliability is unknown 16 , the accuracy of this semi-quantitative evaluation of regurgitation severity needs further study, the 4D-flow, which produces a direct quantification of MR by quantifying flow directly at the valve and is valid in the presence of multiple valve lesions or shunt flow 34 , to investigate the clinical benefit in quantification regurgitation are warranted.…”

Assessment of mitral valve regurgitation by cardiovascular magnetic resonance imaging

“…Direct quantification of the regurgitant jet is particularly useful in pathologies involving multiple valves. A systematic review of 4D flow-derived methods for MR quantification identified seven studies that demonstrated that 4D flowderived MR volume is similar to that derived using standard CMR methods and even to that derived using 3D transoesophageal echocardiography (TOE) methods 29 . In one study, a standard CMR method for quantification of MR volume and 4D flow-derived methods yielded similar results 30 .…”