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

Area of Science:

• Cardiology
• Medical Imaging
• Biomarkers

Background:

• Left ventricular global longitudinal strain (GLS) measured by cardiovascular magnetic resonance (CMR) is a key prognostic biomarker.
• Clinical adoption of GLS is hindered by diverse methodologies and postprocessing variability among users and vendors.
• Standardization of postprocessing can mitigate operator-dependent variability, enabling measurement comparability.

Purpose of the Study:

• To investigate and reduce the random variability in GLS measurements through optimized postprocessing steps.
• To enhance observer reproducibility and agreement in GLS quantification.
• To establish a standardized postprocessing approach for CMR-derived GLS.

Main Methods:

• Two independent observers analyzed cine images (2, 3, and 4-chamber views) using two different CMR feature-tracking (FT) software.
• Stepwise adjustments were systematically applied to optimize postprocessing, assessing their impact on inter-observer and inter-vendor bias.
• Variability was evaluated using Bland-Altman analyses, intra-class correlation coefficients (ICCs), and coefficients of variation (CVs) in 44 subjects.

Main Results:

• Standardization significantly improved GLS measurement consistency, accentuating differences between patient groups and controls.
• Post-standardization, intra-observer variability CVs decreased from 7.6% and 4.6% to 3.1% and 4.3%.
• Inter-observer variability CVs improved from 11% and 4.7% to 5.2% and 4.4% across vendors, with enhanced ICC agreement.

Conclusions:

• Standardization effectively reduces random variability in GLS measurements stemming from observer and inter-vendor inconsistencies.
• While standardization addresses random error, systematic inter-vendor bias related to image processing algorithms persists.
• Implementing standardized GLS measurements is crucial for reliable myocardial deformation quantification and routine clinical use of CMR-FT.