Calculation of right ventricular stroke volume in short‐axis MR images using the equation of the tricuspid plane

Abstract

Short-axis (SA) magnetic resonance (MR) images are commonly planned parallel to the left atrioventricular valve. This orientation leads to oblique slices of the right ventricle (RV) with subsequent difficulties in separating the RV from the right atrium in the SA images. The insertion points of the tricuspid valve (TV) in the myocardium can be clearly identified in the right ventricle long axis (RVLA) and four-chamber (4CH) views. The purpose of this study was to develop a method that transfers the position of the tricuspid plane, as seen in the RVLA and 4CH views, to the SA images to facilitate the separation of the RV from the atrium. This methodology, termed Dissociating the Right Atrium from the Ventricle Volume (DRAW), was applied in 20 patients for calculations of right ventricular stroke volume (RVSV). The RVSV using DRAW (RVSV(DRAW)) was compared to left ventricular stroke volumes (LVSV) obtained from flow measurements in the ascending aorta. The RVSV was also determined using the conventional method (RVSV(CONV)) where the stack of images from the SA views are summarized, and a visual decision is made of the most basal slice to be included in the RV. The mean difference between RVSV(DRAW) and LVSV was 0·1 ± 12·7 ml, while the mean difference between RVSV(CONV) and LVSV was 0·33 ± 14·3 ml. Both the intra- and interobserver variability were small using the DRAW methodology, 0·6 ± 3·5 and 1·7 ± 2·7 ml, respectively. In conclusion, the DRAW method can be used to facilitate the separation of the RV and the atrium.

Determination of Right Ventricular Volume by Combining Echocardiographic Distance Measurements

“…Regarding CMR, the endocardial contours were outlined in both end-diastolic and end-systolic phases in all SA slices, following summation of all slices to generate the end-diastolic and end-systolic volumes (EDV and ESV) for both the LV and the RV. 17,18 Based on these volumes, the left ventricular stroke volume (LVSV) and the RVSV could be determined (LVSV CMR SA and RVSV CMR SA ). The LVSV was also estimated by CMR flow measurements in the aorta ascendens (LVSV CMR Flow ).…”

A study to determine the contribution to right ventricle stroke volume from pulmonary and tricuspid valve displacement volumes

“…In CMR, the governing principles for measuring LV and RV function are the same but, due to the difficulties presented by the more complex shape of the RV, research aimed at developing more applicable methods for the RV continues (Strugnell et al ., ; Aneq et al ., ; Jorstig et al ., ). In echocardiography, different parameters are used to describe RV function, for example tricuspid annulus motion (TAM) (Armstrong & Ryan, ), right ventricular fractional area change (RVFAC) (Rudski et al ., ) and right ventricular outflow tract fractional shortening (RVOTFS) (Lindqvist et al ., ).…”