Axial strain calculation using a low-pass digital differentiator in ultrasound elastography

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Signal Processing

Background:

• Ultrasound elastography estimates tissue properties by analyzing tissue deformation under external stress.
• Calculating axial strain relies on differentiating estimated axial displacements, which amplifies noise, particularly at high frequencies.
• This noise amplification degrades the accuracy of elastographic measurements.

Purpose of the Study:

• To propose and evaluate a low-pass digital differentiator (LPDD) for calculating axial strain in ultrasound elastography.
• To mitigate noise amplification inherent in conventional differentiation methods.
• To improve the accuracy and reliability of ultrasound elastography strain estimations.

Main Methods:

• Implementation of several well-established low-pass digital differentiators (LPDDs).
• Quantitative and qualitative performance comparison of different LPDDs.
• Validation through computer simulations, phantom studies, and in vitro experiments.

Main Results:

• The proposed LPDD method effectively reduces noise amplification during axial strain calculation.
• Performance comparisons demonstrated the superiority of LPDDs over conventional differentiation in simulated and experimental settings.
• Experimental results aligned with theoretical predictions for LPDD performance.

Conclusions:

• Low-pass digital differentiators offer a robust solution for accurate axial strain estimation in ultrasound elastography.
• The LPDD technique enhances the reliability of ultrasound elastography by minimizing noise-induced errors.
• This approach holds potential for improving diagnostic capabilities in medical imaging.