Influence of temporal resolution on computed tomography feature-tracking strain measurements

Area of Science:

• Cardiology
• Medical Imaging
• Biomedical Engineering

Background:

• Temporal resolution is critical for accurate strain measurements in cardiac imaging.
• Feature-tracking techniques, including CT-FT, are sensitive to variations in image acquisition and reconstruction.
• Understanding factors influencing strain quantification is vital for clinical diagnosis and research.

Purpose of the Study:

• To investigate the impact of R-R interval reconstruction increments on left ventricular (LV) and left atrial (LA) strain measurements derived from CT feature-tracking (CT-FT).
• To assess how different reconstruction step sizes (5% vs. 10%) affect strain values and their reproducibility.

Main Methods:

• Retrospective analysis of electrocardiogram-gated coronary CT angiography (CCTA) images.
• Reconstruction of CCTA images at 5% and 10% R-R interval steps.
• Computation of LV and LA strain parameters (GLS, GCS, GRS), ejection fraction (EF), and atrioventricular coupling indices.
• Evaluation of consistency, variability, demarcation between LA phases, and observer reproducibility.

Main Results:

• A 5% R-R increment resulted in significantly larger absolute strain values compared to a 10% increment.
• LV radial strain (GRS) showed the greatest difference between reconstruction groups.
• Group differences were attenuated in subgroups with heart rates >80 bpm or impaired cardiac function.
• A 5% increment increased the prevalence of definite demarcation between LA conduit and contraction phases.
• Higher average heart rate was associated with indefinite LA phase demarcation, independent of LVEF.
• Observer reproducibility was not affected by the R-R reconstruction increment.

Conclusions:

• R-R interval reconstruction increment is a significant source of variation in CT-FT derived LV and LA strain.
• Controlling heart rate and using a narrow R-R reconstruction increment (e.g., 5%) is crucial for accurate phasic LA strain quantification.
• These findings highlight the importance of standardized reconstruction protocols in CT-FT analysis.