Cardiac MR elastography: comparison with left ventricular pressure measurement

Area of Science:

• Cardiovascular imaging
• Biomedical engineering
• Medical physics

Background:

• Assessing cardiac pressure-volume function is crucial for diagnosing and managing heart conditions.
• Current methods for measuring ventricular pressure are invasive, limiting their routine clinical use.
• Noninvasive imaging techniques are needed to provide accurate and accessible cardiac function assessments.

Purpose of the Study:

• To compare the efficacy of magnetic resonance elastography (MRE) in reflecting ventricular pressure changes.
• To evaluate the correlation between MRE-derived shear wave amplitudes and invasive left ventricular (LV) pressure measurements in an animal model.

Main Methods:

• Three pigs with varying cardiac physiology underwent invasive LV pressure monitoring and noninvasive cardiac MRE.
• Cardiac MRE utilized a short-axis view with a 48.3-Hz shear-wave stimulus.
• Analysis focused on relative changes in LV shear wave amplitudes during the cardiac cycle and their correlation with LV pressure and diameter.

Main Results:

• A significant relationship was observed between MRE shear wave amplitudes and LV pressure (R2 >= 0.76) across all animals.
• No significant correlation was found between MRE and LV diameter (R2 <= 0.15).
• Shear wave amplitudes preceded changes in LV diameter during systole and diastole, reflecting pressure dynamics.

Conclusions:

• Externally induced shear waves in cardiac MRE provide valuable information reflecting intraventricular pressure changes.
• These findings suggest cardiac MRE could become a unique noninvasive tool for measuring heart pressure-volume function.
• Further research is warranted to validate these preliminary results in larger studies.