Confounders, diagnostic accuracy, and reproducibility in cardiovascular magnetic resonance-feature tracking-derived left atrial strain: A Berlin Research Network for cardiovascular magnetic resonance multi-software, multi-site comparison

Cardiovascular Magnetic Resonance-feature tracking (CMR-FT) derived left atrial global longitudinal strain (LA-GLS) has prognostic relevance, even in the early stages of cardiovascular diseases. Identifying technical and subject-related confounders is essential for ensuring comparability across sites and for reliably distinguishing healthy from pathological conditions. This study aimed to evaluate the influence of post-processing software and subject-related factors on CMR-FT derived LA-GLS, diagnostic accuracy and to evaluate inter-site reproducibility. This study included 149 healthy individuals and 40 patients with atrial fibrillation (AF; 19 persistent, 21 paroxysmal) from a single site. A subgroup of 18 traveling volunteers underwent CMR at four different sites. All participants underwent CMR in sinus rhythm. LA-GLS was assessed using three post-processing software packages (CVI42, TrufiStrain Research Prototype, Medis). Mixed models with repeated measures were applied to evaluate the effect of software, site and subject-related factors on LA-GLS components. ROC curve analysis was used to assess diagnostic accuracy across software in distinguishing healthy controls from AF patients. All GLS components differed across post-processing software (p