Analysis of the Influence of Tumor Size on the Measure of Shear Wave Elastography and Strain Elastography: A Phantom...

To investigate the impact of tumor diameter on shear wave elastography (SWE) and strain elastography (SE) stiffness measurements and establish selection criteria for clinical application.

A gelatin phantom containing 28 inclusions (two stiffness levels: 56.1 ± 2.3 kPa and 83.3 ± 1.8 kPa) with diameters ranging 3-22 mm (14 sizes, namely 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20 and 22 mm) at fixed depth was analyzed. SWE-derived mean Young's modulus (E1), modulus ratio (ER) and SE-derived strain ratio (SRR) were measured. Spearman correlation analysis was performed to assess relationships between diameters and parameters.

SWE measurements exhibited significant positive correlations between diameters and both E1 and ER (p < 0.05) across all stiffness levels. Measurement accuracy improved with increasing diameter, stabilizing at ≥16 mm, where values approximated phantom specifications. SE measurements demonstrated diameter-independent stability, maintaining consistent ratios across all sizes.

SWE measurements show significant size dependency, substantially underestimating stiffness in sub-16 mm lesions, while SE provides reliable measurements regardless of tumor size. These findings suggest SE may be preferable for small tumor assessment (<16 mm), whereas SWE requires cautious interpretation until lesions reach 16 mm diameter. This diameter-dependent performance pattern informs protocol optimization for clinical elastography applications.