Longitudinal strain from velocity encoded cardiovascular magnetic resonance: a validation study

Area of Science:

• Cardiovascular Imaging
• Biomedical Engineering
• Medical Physics

Background:

• Traditional assessment of regional myocardial function relies on subjective visual evaluation or time-consuming post-processing methods.
• Quantitative assessment is crucial for accurate diagnosis and management of cardiac conditions.
• Velocity encoded cardiovascular magnetic resonance (CMR) offers potential for objective functional analysis.

Purpose of the Study:

• To develop and validate a straightforward method for deriving quantitative regional myocardial function from velocity encoded CMR.
• To establish normal values for longitudinal strain using the developed technique.
• To assess the clinical applicability of the method for evaluating myocardial wall function.

Main Methods:

• Velocity encoded CMR (FFE and TFE sequences) was performed on 36 healthy volunteers and 10 myocardial infarction patients.
• A novel method was developed to track myocardial deformation throughout the cardiac cycle using optimization and mechanical assumptions.
• Validation was performed using phantom experiments with optical tracking and comparison with existing methods.

Main Results:

• The developed method demonstrated excellent agreement with optical tracking for longitudinal strain measurement (difference 0.0025 ± 0.085).
• Mean global longitudinal strain in healthy volunteers was -0.18 ± 0.10 (TFE imaging), with low intra- and inter-observer variability.
• Patients post-myocardial infarction showed significantly lower longitudinal strain compared to healthy controls, particularly in infarcted regions.

Conclusions:

• A robust and clinically applicable technique for quantifying longitudinal strain and regional myocardial function using velocity encoded CMR has been successfully developed and validated.
• The study provides essential normal values for longitudinal strain, facilitating clinical interpretation.
• This method offers a significant advancement over subjective visual assessment and complex post-processing techniques for evaluating myocardial function.