Cardiovascular magnetic resonance feature tracking in pigs: a reproducibility and sample size calculation study

Area of Science:

• Cardiology
• Biomedical Engineering
• Veterinary Medicine

Background:

• Cardiovascular magnetic resonance feature tracking (CMR-FT) is a non-invasive method for assessing myocardial motion and deformation.
• While standardized in humans, its application and reproducibility in animal models, particularly pigs, require further investigation.

Purpose of the Study:

• To evaluate the reproducibility of global strain measurements using CMR-FT in pigs under varying inotropic conditions.
• To determine the sample size needed for future studies investigating relative changes in myocardial strain in pigs.

Main Methods:

• Ten healthy Landrace pigs underwent CMR-FT at baseline, during dobutamine-induced hyper-contractility, and verapamil-induced hypocontractility.
• Global longitudinal strain (GLS), circumferential strain (GCS), and radial strain (GRS) were assessed for inter- and intra-observer reproducibility.
• Sample size calculations were performed based on GLS reproducibility.

Main Results:

• CMR-FT exhibited good to excellent inter- and intra-observer reproducibility in pigs across all tested inotropic states.
• Global longitudinal strain (GLS) showed the highest inter-observer reproducibility at baseline (ICC 0.88) and during verapamil administration (ICC 0.79).
• Sample size calculations indicated that a small number of animals would suffice for future trials using GLS.

Conclusions:

• CMR-FT is a reproducible technique for assessing myocardial strain in pigs, even under altered contractility.
• The findings support the use of CMR-FT in preclinical cardiovascular research in pigs.
• This study provides a basis for designing future animal studies with optimized sample sizes.