Non-Contact Assessment of Cardiac Velocity Profiles Using Ultrasound Based Surface Motion Camera: A Feasibility Study

Area of Science:

• Cardiovascular Imaging
• Biomedical Engineering
• Medical Diagnostics

Background:

• Tissue Doppler imaging (TDI) is vital for cardiac diagnosis but requires expert operation.
• Seismocardiography offers an easier alternative for cardiac timing but lacks direct velocity correlation.
• Current contact accelerometers are limited to single-channel measurements.

Purpose of the Study:

• To introduce a non-contact, multichannel surface motion camera (SMC) using airborne ultrasound.
• To validate the SMC's ability to record cardiac-induced chest surface velocities.
• To assess the correlation between SMC-derived velocities and TDI measurements.

Main Methods:

• A validation study involved 30 healthy subjects with simultaneous ECG, SMC, and echocardiography recordings.
• Airborne ultrasound surface motion camera (SMC) used for non-contact, multichannel chest surface velocity recording.
• Correlation and discrete time warping analyses compared SMC data with TDI velocity waves.

Main Results:

• SMC surface velocity waveforms showed >0.6 correlation similarity with TDI velocity waves.
• Quantitative parameters (peak systolic velocity, amplitude ratio) exhibited R² > 0.8 linear correlation with TDI values.
• Multichannel recording enabled visualization of velocity profiles and spatial variations.

Conclusions:

• The novel airborne ultrasound SMC is a promising non-contact technique for cardio-mechanical monitoring.
• It offers potential for robust, expert-free cardiac diagnostics.
• Multichannel capabilities enhance spatial assessment of cardiac function.