Cadour et al. Journal of Cardiovascular Magnetic Resonance (2023) 25:7 https://doi.org/10.1186/s12968-023-00919-y RESEARCH © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Open Access Journal of Cardiovascular Magnetic Resonance Prognostic value of cardiovascular magnetic resonance T1 mapping and extracellular volume fraction in nonischemic dilated cardiomyopathy Farah Cadour 1,2 , Morgane Quemeneur 1,2 , Loic Biere 3,4 , Erwan Donal 5 , Zakarya Bentatou 1,2 , Jean‑Christophe Eicher 6 , François Roubille 7 , Alain Lalande 8,9 , Roch Giorgi 10 , Stanislas Rapacchi 1,2 , Sébastien Cortaredona 11,12 , Farouk Tradi 1,2 , Axel Bartoli 1,2 , Serge Willoteaux 4 , François Delahaye 13 , Stephanie M. Biene 14 , Lionel Mangin 15 , Nadine Ferrier 16 , Jean‑Nicolas Dacher 17 , Fabrice Bauer 18 , Guillaume Leurent 5 , Pierre‑Axel Lentz 19 , Hélène Kovacsik 20 , Pierre Croisille 21,22 , Franck Thuny 23 , Monique Bernard 1,2,25* , Maxime Guye 1,2 , Alain Furber 3,4 , Gilbert Habib 24 and Alexis Jacquier 1,2 Abstract Background Heart failure‑ (HF) and arrhythmia‑related complications are the main causes of morbidity and mortality in patients with nonischemic dilated cardiomyopathy (NIDCM). Cardiovascular magnetic resonance (CMR) imaging is a noninvasive tool for risk stratifcation based on fbrosis assessment. Difuse interstitial fbrosis in NIDCM may be a limitation for fbrosis assessment through late gadolinium enhancement (LGE), which might be overcome through quantitative T1 and extracellular volume (ECV) assessment. T1 and ECV prognostic value for arrhythmia‑related events remain poorly investigated. We asked whether T1 and ECV have a prognostic value in NIDCM patients. Methods This prospective multicenter study analyzed 225 patients with NIDCM confrmed by CMR who were fol‑ lowed up for 2 years. CMR evaluation included LGE, native T1 mapping and ECV values. The primary endpoint was the occurrence of a major adverse cardiovascular event (MACE) which was divided in two groups: HF‑related events and arrhythmia‑related events. Optimal cutofs for prediction of MACE occurrence were calculated for all CMR quantitative values. Results Fifty‑eight patients (26%) developed a MACE during follow‑up, 42 patients (19%) with HF‑related events and 16 patients (7%) arrhythmia‑related events. T1 Z‑score (p = 0.008) and global ECV (p = 0.001) were associated with HF‑related events occurrence, in addition to left ventricular ejection fraction (p < 0.001). ECV > 32.1% (optimal cutof) remained the only CMR independent predictor of HF‑related events occurrence (HR 2.15 [1.14–4.07], p = 0.018). In the arrhythmia‑related events group, patients had increased native T1 Z‑score and ECV values, with both T1 Z‑score > 4.2 and ECV > 30.5% (optimal cutofs) being independent predictors of arrhythmia‑related events occurrence (respec‑ tively, HR 2.86 [1.06–7.68], p = 0.037 and HR 2.72 [1.01–7.36], p = 0.049). Conclusions ECV was the sole independent predictive factor for both HF‑ and arrhythmia‑related events in NIDCM patients. Native T1 was also an independent predictor in arrhythmia‑related events occurrence. The addition of ECV *Correspondence: Monique Bernard monique.bernard@univ‑amu.fr Full list of author information is available at the end of the article