European Journal of Radiology 85 (2016) 1322–1328 Contents lists available at ScienceDirect European Journal of Radiology j ourna l h o mepage: www.elsevier.com/locate/ejrad Right ventricular long axis strain—validation of a novel parameter in non-ischemic dilated cardiomyopathy using standard cardiac magnetic resonance imaging Nisha Arenja a , Johannes H. Riffel a , Charly Noel Djiokou a , Florian Andre a , Thomas Fritz a , Manuel Halder a , Thomas Zelniker a , Arnt V. Kristen a , Grigorios Korosoglou a , Hugo A. Katus a,b , Sebastian J. Buss a,∗ a Department of Cardiology, Angiology and Pneumology, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany b DZHK (German Centre for Cardiovascular Research), partner site Heidelberg, Germany a r t i c l e i n f o Article history: Received 29 February 2016 Received in revised form 22 April 2016 Accepted 28 April 2016 Keywords: Cardiac magnetic resonance imaging Non-ischemic dilated cardiomyopathy Right ventricular function Long axis strain a b s t r a c t Purpose: Right ventricular longitudinal axis strain (RV-LAS) is a simple measure of RV longitudinal func- tion. The purpose of this study was the evaluation of its diagnostic performance in non-ischemic dilated cardiomyopathy (NIDCM) and the determination of reference values in controls. Methods: 217 NIDCM patients and 200 healthy controls were analysed retrospectively regarding the diagnostic performance of RV-LAS using receiver operating characteristic curves in comparison with RV ejection fraction (RVEF), tricuspid annular plane systolic excursion (TAPSE) and global longitudinal strain (RV-GLS). Hereby, four different approaches were evaluated to assess RV-LAS based on different reference points. RV-LAS LVapex/mid was defined as the change in distance between the LV apex and the middle of a line connecting the origins of the tricuspidal valve leaflets in systole and diastole. The ethical approval was obtained in all participants. Results: NIDCM and controls were 48 years in mean. Controls were equally gender distributed, while the proportion of men with NIDCM was higher with 77%. Among the four approaches RV-LAS LVapex/mid pro- vided the highest diagnostic performance for discrimination between NIDCM and controls (AUC = 0.94). Of all RV functional parameters RV-LAS LVapex/mid preformed significantly better than RVEF (delta AUC = 0.05; p = 0.003), TAPSE (delta AUC = 0.23; p < 0.0001) and RV-GLS (delta AUC = 0.31; p < 0.0001). A significant correlation was found between RV-LAS LVapex/mid and RVEF (r = -0.65; p < 0.0001). The reference mean values for RV-LAS LVapex/mid were -17.4 ± 3.5 for men and -18.5 ± 3.7 for women. Conclusion: RV-LAS showed better diagnostic accuracy for RV dysfunction than RVEF, TAPSE and RV-GLS. Furthermore, it has a rapid accessibility and low intra- and interobserver variability. © 2016 Elsevier Ireland Ltd. All rights reserved. Abbreviations: ARVC, arrhythmogenic right ventricular cardiomyopathy; AUC, area under curve; CMR, cardiac magnetic resonance; ECG, electrocardiogram; EDV, end-diastolic volume; EF, ejection Fraction; ESV, end-systolic volume; FTI, feature tracking analysis; FOV, field of view; GLS, global longitudinal strain; LAS, long axis strian; LV, left ventricle; NIDCM, non-ischemic dilated cardiomyopathy; NYHA, New York heart association-classification; ROC, receiver operating characteristic; RV, right ventricle; RV-GLS, right ventricular global longitudinal strain; RVEF, right ventricular ejection fraction; RV-LAS, right ventricular longitudinal axis strain; SD, standard deviation; SSFP, steady state free precession sequence; SV, stroke volume; TAPSE, tricuspid annular plane systolic excursion; TE, echo time; TR, repetition time. ∗ Corresponding author. E-mail address: sebastian.buss@med.uni-heidelberg.de (S.J. Buss). 1. Introduction Non-ischemic dilated cardiomyopathy (NIDCM) is defined as systolic dysfunction, either of the left ventricle (LV) alone or biven- tricular, with concomitant dilatation in the absence of abnormal loading conditions or coronary artery disease [1]. Right ventricular (RV) dysfunction is known to come along with limited exercise capacity and to worsen significantly the prognosis in NIDCM. Therefore, the evaluation of the RV function is of crucial importance in patients with NIDCM [2–4]. Compared with the LV measurement, RV function is often dif- ficult to assess, due to the complex geometry and motion of the RV. For the assessment of RV function cardiac magnetic resonance (CMR) imaging has been shown to be both, accurate and repro- http://dx.doi.org/10.1016/j.ejrad.2016.04.017 0720-048X/© 2016 Elsevier Ireland Ltd. All rights reserved.