Does standoff material affect acoustic radiation force impulse elastography? A preclinical study of a modified...

Area of Science:

• Medical Imaging
• Ultrasound Elastography
• Biomedical Engineering

Background:

• Acoustic Radiation Force Impulse (ARFI) elastography measures tissue stiffness.
• Standoff materials are sometimes used to improve ultrasound coupling and image quality.
• The impact of standoff materials on ARFI measurements requires further investigation.

Purpose of the Study:

• To evaluate the influence of porcine muscle as a standoff material on ARFI measurements.
• To compare the performance of a convex and a linear probe under these conditions.

Main Methods:

• ARFI elastography was performed on an elasticity phantom using convex (4C1) and linear (9L4) probes.
• Porcine muscle was used as an interposed standoff material in some experimental setups.
• Shear Wave Velocity (SWV) was measured, and probe pressure was recorded.

Main Results:

• The linear 9L4 probe showed a significantly higher rate of faulty ARFI measurements (52.4%) when using muscle standoff, particularly on harder lesions.
• SWV values measured with the 9L4 probe were higher and showed increased deviation and variance with the muscle standoff.
• The convex 4C1 probe demonstrated better accuracy and lower variance compared to the 9L4 probe.

Conclusions:

• Porcine muscle as a standoff material significantly affects ARFI measurement accuracy and reliability.
• The linear high-frequency probe (9L4) is particularly susceptible to errors introduced by standoff materials.
• Careful consideration of standoff material use is crucial for accurate ARFI elastography, especially with high-frequency probes.