Evaluation of parietal pleural adhesion and invasion in subpleural lung cancer: value of B-mode ultrasound and contrast-enhanced ultrasound.

Abstract

The parietal pleural adhesion/invasion of lung cancer can contribute substantially to poor prognosis and difficulty in surgery. The value of ultrasound in evaluating the parietal pleural adhesion or invasion (pleural adhesion/invasion) of lung cancer remains uncertain. This study investigated the value of B-mode ultrasound and contrast-enhanced ultrasound (CEUS) in diagnosing parietal pleural adhesion/invasion of subpleural lung cancer. The study animals included 40 male New Zealand white rabbits. A rabbit subpleural lung cancer model was constructed by injecting VX2 tumor tissue under ultrasound guidance. In the 1-3 weeks after subpleural lesion formation, parietal pleural adhesion/invasion of the largest subpleural lesion was evaluated with B-mode ultrasound and CEUS by two sonographers. The parietal pleural adhesion/invasion was also determined using the gold standard method of findings from anatomical and pathological examination. Ultimately, 34 rabbits were subjected to complete ultrasonic evaluation. There were 20 and 14 cases with and without parietal pleural adhesion/invasion, respectively, as confirmed by anatomical and pathological evaluations. The diagnostic sensitivity, specificity, and accuracy of sonographer 1 using B-mode ultrasound were 50.0% [95% confidence interval (CI): 26.0-74.0%], 100%, and 70.6% (95% CI: 54.5-86.7%), respectively; for CEUS, they were 90.0% (95% CI: 75.6-100.0%), 100.0%, and 94.1% (95% CI: 85.8-100.0%), respectively. The diagnostic sensitivity, specificity, and accuracy of sonographer 2 using B-mode ultrasound were 45.0% (95% CI: 21.1-68.9%), 92.9% (95% CI: 77.5-100.0%), and 64.7% (95% CI: 47.8-81.6%), respectively; for CEUS, they were 85.0% (95% CI: 67.9-100.0%), 100.0%, and 91.2% (95% CI: 81.1-100.0%), respectively. The diagnostic accuracy of sonographer 1 was higher with CEUS than with B-mode ultrasound, but not significantly so (94.1% vs. 70.6%; P=0.08). The diagnostic accuracy of sonographer 2 was significantly higher with CEUS than with B-mode ultrasound (91.2% vs. 64.7%; P=0.03). The interrater reliability was higher for CEUS than for B-mode ultrasound (κ=0.941 vs. κ =0.717). Based on an animal model, B-mode ultrasound and CEUS both exhibited good diagnostic efficacy and interrater reliability in evaluating parietal pleural adhesion/invasion of subpleural lung cancer although CEUS outperformed B-mode ultrasound for both measures.