Elastography is currently used in various organs including the thyroid, breast, liver, prostate, and lymph nodes. Nonetheless, few studies have investigated the application of ultrasound elastography in lungs in humans and it is not yet applied in dogs.
The purpose of this study was to investigate the feasibility and application of transthoracic ultrasound elastography in pulmonary lesions in dogs.
Thirteen cadavers were prospectively obtained from dogs scheduled to undergo euthanasia. A radiofrequency (RF) ablation was utilized to create thermal lesions in cadaver lung. Before and after RF ablation, strain ratios were obtained. The strain index, defined as the muscle to lesion strain ratio (B/A ratio), was calculated automatically by the software program in the ultrasound unit.
The average strain values of dogs with latissimus dorsi muscle (LDM), intercostal muscle (ICM), and pulmonary lesion were 1.80±0.17, 0.52±0.1, and 0.43±0.09, respectively, whereas the strain value of the lung was 0.01±0.001. There were statistically significant differences in tissue hardness. The strain ratio of LDM/lung was significantly different from that of LDM/lesion (180.27±16.83 vs. 4.17±0.94, p<0.001). The strain ratio of ICM/lung was significantly different from that of ICM/lesion (51.88±9.52 vs. 1.15±0.25, p<0.001).
The elasticity of lung tissue affected by RF ablation and normal lung is quantitatively reflected by strain ratio obtained with ultrasound. This study provides basic information for strain values and strain ratios for the pulmonary lesion in dogs.