Myofiber strain in healthy humans using DENSE and cDTI

Area of Science:

• Cardiovascular imaging
• Cardiac mechanics
• Biomarker development

Background:

• Myofiber strain (Eff) is a key metric for cardiac cell shortening and evaluating cardiomyocyte contractility.
• Assessing Eff in vivo is crucial for understanding cardiac function and dysfunction.

Purpose of the Study:

• To develop and validate an efficient pipeline for in vivo estimation of myofiber strain (Eff).
• To assess the spatial uniformity of Eff in healthy volunteers.

Main Methods:

• A novel pipeline combining diffusion tensor imaging (cDTI) and displacement encoding with stimulated echoes (DENSE) MRI was developed.
• The pipeline processed DENSE and cDTI data to generate 3D myofiber orientations and compute Eff in vivo.
• Computational phantom studies assessed pipeline precision, and transmural Eff was compared to circumferential strain (Ecc) in 30 healthy volunteers.

Main Results:

• The developed pipeline enabled in vivo measurement of myofiber strain within an average acquisition time of 11 minutes.
• Computed Eff was found to be transmurally uniform in healthy volunteers.
• Eff demonstrated less variability compared to circumferential strain (Ecc) across different myocardial layers.

Conclusions:

• This study successfully demonstrated the feasibility of measuring in vivo myofiber strain efficiently in a healthy human population.
• The observed spatial uniformity of myofiber strain suggests its potential as a sensitive biomarker for assessing local cardiomyocyte contractility and cardiovascular dysfunction.