Automated flow quantification in valvular heart disease based on backscattered Doppler power analysis: implementation...

Area of Science:

• Cardiovascular Imaging
• Medical Ultrasound Technology
• Hemodynamics

Background:

• Current cardiac ultrasound methods for valvular regurgitation quantification rely on indirect measurements and inaccurate hemodynamic assumptions.
• Direct flow quantification at the vena contracta using integrated Doppler power and velocity has been previously demonstrated.

Purpose of the Study:

• To implement automated Doppler power flow analysis software on a standard cardiac ultrasound system.
• To detail the system requirements, components, and software for this novel approach.
• To validate the system using experimental, in vitro, and in vivo testing.

Main Methods:

• A 3.5 MHz matrix-array cardiac ultrasound scanner (Sonos 5500) was utilized.
• Validation involved experimental signal generator trials, in vitro flow phantom studies, and in vivo testing in 48 patients with mitral regurgitation.
• Magnetic resonance imaging (MRI) served as the reference standard.

Main Results:

• The automated Doppler power flow analysis showed good correlation with reference MRI values.
• Successful implementation on a matrix-array ultrasound system was confirmed.
• Underestimation of larger regurgitant orifice areas and volumes was noted, attributed to Doppler beam width limitations, suggesting potential for improvement with new 2D matrix-array technology.

Conclusions:

• Automated flow quantification in valvular heart disease using backscattered Doppler power is feasible on standard matrix-array ultrasound systems.
• This technique provides direct, noninvasive, and user-independent analysis of valvular regurgitant flow.
• The automated Doppler power flow analysis overcomes practical limitations of existing quantification methods.