Characterizing vortex ring behavior during ventricular filling with Doppler echocardiography: an in vitro study

Area of Science:

• Cardiovascular fluid dynamics
• Medical imaging analysis
• Diastolic function assessment

Background:

• Doppler ultrasound color M-mode imaging (CMM) is a proposed noninvasive method for quantifying diastolic function.
• The precise relationship between CMM-derived parameters and actual fluid dynamics remains unclear.

Purpose of the Study:

• To investigate the relationship between CMM flow propagation and left ventricular inflow dynamics.
• To couple high-resolution velocimetry with CMM measurements in an in vitro model.

Main Methods:

• Utilized an in vitro model of left ventricular inflow under two Reynolds number conditions (4000 and 6000).
• Employed high-resolution Particle Image Velocimetry (PIV) and CMM for measurements.
• Extracted two flow propagation parameters from CMM data: isovelocity marker and local peak velocity marker.

Main Results:

• CMM centerline velocities showed agreement with PIV velocities, despite significant uncertainty (+/- 10 cm s(-1)).
• The isovelocity method tracked the flow wavefront, while the peak velocity method tracked vortex propagation.
• Both flow conditions generated starting jets forming vortex rings.

Conclusions:

• CMM imaging, though limited in absolute velocity measurement, can effectively assess inflow vortex ring properties.
• CMM provides valuable insights into diastolic function by characterizing flow dynamics.