The role of lung ultrasound and ultrasound elastography in diagnosis of interstitial lung diseases.

Introduction: Ultrasound elastography (US-E) is a novel, tissue stiffness-sensitive imaging method. We aimed to investigate whether lung ultrasound (US) and US-E can play a role in diagnosing interstitial lung diseases (ILDs) in which lung elasticity is affected due to fibrosis.

Materials and methods: A prospective cohort study. Patients with ILD were defined as ''ILD group'' and with other pulmonary diseases as ''control group". All subjects were examined and compared by lung US in B and elastography modes. Besides, the relationship between ultrasonography and high-resolution computerized tomography (HRCT) and chest X-ray findings was evaluated.

Result: A total of 109 patients, 55 in ILD and 54 in the control group, with a mean age of 62 ± 14 years, were included. A positive correlation was found between the Warrick score (calculated from HRCT to determine the severity of ILD) and the number of B-lines (discrete vertical reverberation artifacts, indicating interstitial lung syndrome) in lung US (p= 0.001, r= 0.550) in the ILD group. In US-E, blue color (meaning more rigid tissue) dominated in the ILD group, and green color (indicating medium tissue stiffness) dominated in the control group (p= 0.001). Lung US diagnosed the ILD with 69% accuracy, 80% sensitivity, and 60% specificity compared to HRCT. Combined with chest X-ray, diagnostic accuracy was 74%, sensitivity 60%, and specificity 89%.

Conclusions: Although lung US and US-E are not superior to gold standard HRCT in diagnosing ILDs, they can still be accepted as promising, novel, noninvasive tools, especially when combined with chest X-rays. Their role still needs to be clarified with further studies.