Nonlinearity parameter estimation method from fundamental band signal depletion in pulse-echo using a dual-energy...

Area of Science:

• Biomedical Ultrasound
• Acoustics
• Medical Imaging

Background:

• The nonlinearity parameter (B/A) is crucial for diagnosing conditions like liver steatosis.
• A pulse-echo depletion method was recently proposed to estimate B/A.
• This study provides further technical details and assesses the robustness of the depletion method.

Purpose of the Study:

• To present the pulse-echo depletion method for estimating the nonlinearity parameter (B/A) with enhanced technical detail.
• To evaluate the robustness of the B/A estimation using the depletion method under conditions deviating from ideal model requirements.
• To assess the experimental feasibility and accuracy of the depletion method.

Main Methods:

• Simulations were conducted to assess the depletion method's robustness against deviations from monochromatic plane wave propagation and quadratic power-law frequency dependence attenuation.
• The impact of using wideband versus narrowband pulses on B/A estimation bias was investigated.
• Experimental validation of the depletion method was performed.

Main Results:

• Wideband pulses (37%-113% bandwidth) resulted in larger B/A estimation bias compared to narrowband pulses (11%-28% bandwidth), even when attenuation followed a power law.
• With soft tissue-like power-law frequency dependence (1.1 or 1.2), narrowband pulses yielded <10% bias.
• The method demonstrated robustness against ~60% attenuation mismatches between reference phantom and sample.
• Experimental results showed good accuracy with bias <17%.

Conclusions:

• The depletion method's accuracy in estimating B/A is sensitive to pulse bandwidth, with narrowband pulses being more robust.
• The method shows promise for clinical applications like liver steatosis diagnosis, demonstrating robustness and experimental feasibility.
• Further technical refinement and validation support the clinical potential of B/A estimation via the depletion method.