Researchers find quick fix for RV parameters in pediatric CMR imaging

A group of doctors in Warsaw, Poland, have identified a single parameter for first-line assessment of right ventricular (RV) function in pediatric patients, according to data published in Clinical Radiology this week.

Though echocardiography is the gold standard for evaluating heart function in children, cardiac magnetic resonance imaging (CMR) is most clinicians’ second choice—and it’s a good one—M. Brzewski and colleagues wrote. CMR is non-invasive, reliable and can assess mass, volume and systolic function in both the right and left ventricle (LV). Pediatric patients are typically referred for CMR in the case of suspected cardiomyopathy, congenital heart disease and myocarditis, the researchers said, and can be used to characterize tumor tissue.

“CMR is of particular value in the detailed assessment of the RV, where the use of echocardiography can be limited due to problems with visualization, complex RV anatomy and motion,” Brzewski et al. wrote. “Detailed assessment of the RV is very important in patients where the CMR criteria have an essential value.”

Unlike the left ventricle, the right is harder to image correctly, the authors said. Because of its thinner myocardial wall, calculating CMR parameters for the RV can be a time-consuming, manual process. In turn, LV parameters can be quickly determined using semi-automatic software.

The arduous task of finding RV parameters would be more pressing, though, if it were more common than it is. Many indications for CMR in children, Brzewski and co-authors wrote, concern only suspicion of LV disease, meaning simple one- or two-dimensional parameters would be sufficient for assessing RV volume and systolic function.

“These parameters could be rapidly used as a screening tool to determine those who require more detailed RV analysis, limiting time for study evaluation in many patients,” the researchers wrote.

Seeking a method for more efficient RV evaluation in these cases, the team analyzed 60 pediatric CMR studies, considering RV end-diastolic and end-systolic area (4CH EDA and 4CH ESA), fractional area change (FAC), RV diameter in end-diastole (RVD1), tricuspid annular plane systolic excursion (TAPSE) and RV outflow tract diameter in end-diastole (RVOT prox). Results were correlated with RV end-diastolic volume (RVEDVI) and RV ejection fraction (RVEF), according to the study.

One parameter, 4CH ESA, proved a good predictor of increased RV size and decrease RV volume in pediatric patients, the authors found. Other links were weaker, with a tenuous connection between RVD1 and RVEDVI and no connection at all between TAPSE and RVEF.

A 4CH ESA cut-off value of 8.5 cm2/m2 saw the greatest diagnostic accuracy for predicting an enlarged right ventricle, the researchers wrote, and a 10.5 cm2/m2 cut-off value was the best predictor of depressed RV systolic function.

“For routine screening in clinical practice, 4CH ESA seems a reliable and easy method to identify patients with RV dysfunction,” Brzewski et al. said.