Inter- and intraobserver reproducibility of Strain and 2D Shear Wave Elastography - a phantom study

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Elastography

Background:

• Elastography techniques quantify tissue stiffness using ultrasound.
• Variability in elastographic measurements can impact diagnostic accuracy.
• Standardization of elastography protocols is crucial for reliable clinical application.

Purpose of the Study:

• To analyze intra- and interobserver variability of two elastographic quantification methods.
• To identify technical factors influencing variability, including machine type and region of interest (ROI) size.
• To compare variability between two different ultrasound machines in an in vitro setting.

Main Methods:

• Three silicone experimental devices (ED) were used for in vitro testing.
• Two observers performed repeated measurements using strain elastography and Shear Wave Elastography (SWE) on two ultrasound machines.
• Reproducibility was assessed using Intraclass Correlation Coefficients (ICCs) based on ROI size and stiffness differences.

Main Results:

• Strain elastography demonstrated high inter- and intraobserver reproducibility across both machines.
• A smaller ROI diameter (5 mm) significantly increased strain ratio reproducibility compared to a larger diameter (15 mm) (ICC = 0.87 vs 0.78).
• SWE achieved significant interobserver reproducibility only when analyzing structures with substantial stiffness differences (ICC = 0.75).

Conclusions:

• Both strain elastography and SWE are reproducible techniques for quantifying tissue stiffness.
• Utilizing a smaller ROI diameter enhances interobserver reproducibility in strain elastography.
• SWE's reproducibility is contingent upon significant differences in tissue hardness.