Direct 4D flow CMR jet tracking demonstrated good inter-method agreement for mitral regurgitation volume compared to the indirect volumetric method (ICC 0.80, p=0.004) and higher agreement with echocardiography.
Observational (n=37)
Blinded observers
No
Does direct 4D flow CMR jet tracking improve the reproducibility and accuracy of mitral regurgitation quantification compared to the indirect volumetric method in patients with hypertrophic cardiomyopathy?
4D flow CMR jet tracking provides a highly reproducible, direct method for quantifying mitral regurgitation in hypertrophic cardiomyopathy, overcoming the limitations and variability of standard indirect volumetric calculations.
Effect estimate: ICC 0.80
p-value: p=0.004
BACKGROUND: Quantitative evaluation of mitral regurgitation (MR) in hypertrophic cardiomyopathy (HCM) by cardiovascular magnetic resonance (CMR) relies on an indirect volumetric calculation. The aim of this study was to directly assess and quantify MR jets in patients with HCM using 4D flow CMR jet tracking in comparison to standard-of-care CMR indirect volumetric method. METHODS: This retrospective study included patients with HCM undergoing 4D flow CMR. By the indirect volumetric method from CMR, MR volume was quantified as left ventricular stroke volume minus forward aortic volume. By 4D flow CMR direct jet tracking, multiplanar reformatted planes were positioned in the peak velocity of the MR jet during systole to calculate through-plane regurgitant flow. MR severity was collected for agreement analysis from a clinical echocardiograms performed within 1 month of CMR. Inter-method and inter-observer agreement were assessed by intraclass correlation coefficient (ICC), Bland-Altman analysis, and Cohen's kappa. RESULTS: Thirty-seven patients with HCM were included. Direct jet tracking demonstrated good inter-method agreement of MR volume compared to the indirect volumetric method (ICC = 0.80, p = 0.004) and fair agreement of MR severity (kappa = 0.27, p = 0.03). Direct jet tracking showed higher agreement with echocardiography (kappa = 0.35, p = 0.04) than indirect volumetric method (kappa = 0.16, p = 0.35). Inter-observer reproducibility of indirect volumetric method components revealed the lowest reproducibility in end-systolic volume (ICC = 0.69, p = 0.15). Indirect volumetric method showed good agreement of MR volume (ICC = 0.80, p = 0.003) and fair agreement of MR severity (kappa = 0.38, p < 0.001). Direct jet tracking demonstrated (1) excellent inter-observer reproducibility of MR volume (ICC = 0.97, p < 0.001) and MR severity (kappa = 0.84, p < 0.001) and (2) excellent intra-observer reproducibility of MR volume (ICC = 0.98, p < 0.001) and MR severity (kappa = 0.88, p < 0.001). CONCLUSIONS: Quantifying MR and assessing MR severity by indirect volumetric method in HCM patients has limited inter-observer reproducibility. 4D flow CMR jet tracking is a potential alternative technique to directly quantify and assess MR severity with excellent inter- and intra-observer reproducibility and higher agreement with echocardiography in this population.
Gupta et al. (Mon,) conducted a observational in Hypertrophic cardiomyopathy (n=37). 4D flow CMR direct jet tracking vs. Indirect volumetric method (standard-of-care CMR) was evaluated on Inter-method agreement of MR volume between direct jet tracking and indirect volumetric method (ICC 0.80, p=0.004). Direct 4D flow CMR jet tracking demonstrated good inter-method agreement for mitral regurgitation volume compared to the indirect volumetric method (ICC 0.80, p=0.004) and higher agreement with echocardiography.