Cardiac MR elastography of the mouse: Initial results

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Medical Imaging

Background:

• Cardiovascular diseases often involve altered myocardial contractility and elasticity.
• The mouse is a critical animal model for studying heart disease progression.
• Quantifying dynamic changes in myocardial stiffness is essential for understanding cardiac function.

Purpose of the Study:

• To develop and validate a novel, noninvasive method for measuring myocardial stiffness changes during the cardiac cycle.
• To apply microscopic scale MR elastography (MRE) in a mouse model for assessing cardiac mechanics.
• To investigate the feasibility of MRE for characterizing dynamic elasticity variations in the myocardium.

Main Methods:

• A 400 Hz mechanical wave was applied to healthy mice.
• Electrocardiograph-gated and respiratory-gated cine-MRE was used to capture heart motion.
• The effective stiffness of the left ventricle wall was estimated throughout the cardiac cycle.

Main Results:

• Myocardial stiffness varied significantly during the cardiac cycle, with a stiffness ratio of 0.5-0.67 between end-diastole and end-systole.
• Measured shear wave amplitude variations in the left ventricle wall correlated with estimated stiffness changes.
• The study successfully quantified dynamic stiffness variations in the mouse myocardium.

Conclusions:

• Cardiac MRE is a feasible technique for assessing myocardial stiffness in mouse models.
• This noninvasive approach provides valuable insights into cardiac mechanics and elasticity.
• The findings support the use of MRE for studying cardiomyopathies in preclinical research.