Towards standardized postprocessing of global longitudinal strain by feature tracking - OptiStrain CMR-FT study.

BACKGROUND: Left ventricular global longitudinal strain (GLS) with cardiovascular magnetic resonance (CMR) is an important prognostic biomarker. Its everyday clinical use is limited due to methodological and postprocessing diversity among the users and vendors. Standardization of postprocessing approaches may reduce the random operator-dependent variability, allowing for comparability of measurements despite the systematic vendor-related differences. METHODS: We investigated the random component of variability in GLS measurements by optimization steps which incrementally improved observer reproducibility and agreement. Cine images in two-, three- and four-chamber-views were serially analysed by two independent observers using two different CMR-FT softwares. The disparity of outcomes after each series was systematically assessed after a number of stepwise adjustments which were shown to significantly reduce the inter-observer and intervendor bias, resulting standardized postprocessing approach. The final analysis was performed in 44 subjects (ischaemic heart disease n = 15, non-ischaemic dilated cardiomyopathy, n = 19, healthy controls, n = 10). All measurements were performed blind to the underlying group allocation and previous measurements. Inter- and intra-observer variability were tested using Bland-Altman analyses, intra-class correlation coefficients (ICCs) and coefficients of variation (CVs). RESULTS: Compared to controls, mean GLS was significantly lower in patients, as well as between the two subgroups (p < 0.01). These differences were accentuated by standardization procedures, with significant increase in Cohen's D and AUCs. The benefit of standardization was also evident through improved CV and ICC agreements between observers and the two vendors. Initial intra-observer variability CVs for GLS parameters were 7.6 and 4.6%, inter-observer variability CVs were 11 and 4.7%, for the two vendors, respectively. After standardization, intra- and interobserver variability CVs were 3.1 and 4.3%, and 5.2 and 4.4%, respectively. CONCLUSION: Standardization of GLS postprocessing helps to reduce the random component of variability, introduced by inconsistencies of and between observers, and also intervendor variability, but not the systematic inter-vendor bias due to differences in image processing algorithms. Standardization of GLS measurements is an essential step in ensuring the reliable quantification of myocardial deformation, and implementation of CMR-FT in clinical routine.

High-sensitive troponin is associated with subclinical imaging biosignature of inflammatory cardiovascular involvement in systemic lupus erythematosus.

BACKGROUND: Cardiovascular (CV) involvement in patients with systemic lupus erythematosus (SLE) is presumably subclinical for the major part of its evolution. We evaluated the associations between high-sensitive troponin T (hs-TropT), a sensitive marker of myocardial injury, and CV involvement using cardiac magnetic resonance (CMR). METHODS AND RESULTS: This is a two-centre (London and Frankfurt) CMR imaging study at 3.0 Tesla of consecutive 92 patients with SLE free of cardiac symptoms, undergoing screening for cardiac involvement. Venous samples were drawn and analysed post-hoc for cardiac biomarkers, including hs-TropT, high-sensitive C reactive protein and N-terminal pro brain natriuretic peptide. Compared with age-matched/gender-matched non-SLE controls (n=78), patients had significantly raised cardiac biomarker levels, native T1 and T2, aortic and ventricular stiffness, and reduced global longitudinal strain (p<0.01). In SLE, hs-TropT was significantly and independently associated with native T2, followed by the models including native T1 and aortic stiffness (Χ2 0.462, p<0.01). There were no relationships between hs-TropT and age, gender, CV risk factors, duration of systemic disease, cardiac structure or function, or late gadolinium enhancement. CONCLUSIONS: Patients with SLE have a high prevalence of subclinical myocardial injury as demonstrated by raised high-sensitive troponin levels. CMR with T2 mapping reveals myocardial oedema as the strongest predictor of hs-TropT release, underscoring the inflammatory interstitial remodelling as the main mechanism of injury. Patients without active myocardial inflammation demonstrate diffuse interstitial remodelling and increased vascular stiffness. These findings substantiate the role of CMR in screening of subclinical cardiac involvement. TRIAL REGISTRATION NUMER: NCT02407197; Results.