ECG-gated, mechanical and electromechanical wave imaging of cardiovascular tissues in vivo

Area of Science:

• Biomedical Engineering
• Cardiovascular Imaging
• Ultrasound Technology

Background:

• Cardiac cycle involves complex, rapid tissue motions often missed by conventional imaging due to limited temporal resolution.
• Transient events like valve dynamics and electrical conduction generate motion on the millisecond timescale.
• Accurate imaging of these rapid motions is vital for understanding cardiovascular function and disease.

Purpose of the Study:

• To develop and demonstrate a novel ultrasound imaging method for capturing rapid transient motion in cardiovascular tissues.
• To assess the feasibility of this technique in vivo for analyzing myocardial and arterial dynamics.
• To explore the potential of this method for quantitative assessment of tissue properties and early disease diagnosis.

Main Methods:

• Utilized high-frame-rate ultrasound (up to 8000 fps) synchronized with electrocardiogram (ECG) signals for 2D image acquisition.
• Applied the technique to image transient mechanical waves in the myocardium of anesthetized mice.
• Also imaged the abdominal aorta to assess pulse wave propagation and derive vessel wall properties.

Main Results:

• Successfully imaged the propagation of transient mechanical waves in the myocardium with velocities ranging from 0.44 m/s to 5 m/s.
• Observed pulse wave propagation in the abdominal aorta and calculated the Young's modulus of the vessel wall.
• Demonstrated in vivo feasibility in mice, validating the technique's capability to capture rapid cardiovascular dynamics.

Conclusions:

• The high-frame-rate ultrasound method effectively images rapid transient motions in cardiovascular tissues.
• This technique holds potential for mapping myocardial and arterial stiffness, aiding in the early diagnosis of cardiovascular diseases.
• Further research may establish this method as a valuable tool in clinical cardiovascular assessment.