Utility of lung ultrasound to identify interstitial lung disease An observational study based on the STROBE guidelines

Lung ultrasound (LUS) has recently been used to identify interstitial lung disease (ILD). However, data on the role of LUS in the detection of ILD remain limited. The aim of this study was to investigate the diagnostic value of LUS compared with high-resolution computed tomography (HRCT) in patients with ILD. The retrospective study was carried out by reviewing the medical records of patients with respiratory signs and symptoms discharged from the respiratory ward. Only patients with suspected ILD who underwent HRCT and LUS within a week were selected. ILD was identified with a semi-quantitative score of B-lines >5 and a Warrick score >0 points. The endpoints of LUS in diagnosing ILD (i.e., sensitivity, specificity, positive likelihood ratio [PLR], negative likelihood ratio [NLR], positive predictive value [PPV], and negative predictive value [NPV], and receiver operating characteristic [ROC] curve) was compared with that of HRCT. The reference standard used for the diagnosis of ILD was based on history, clinical findings and examination, and laboratory and instrumental tests, including pulmonary function tests, lung histopathology, and HRCT (without LUS findings). The final clinical diagnosis of ILD was 55 in 66 patients with suspected ILD. HRCT was positive in 55 patients, whereas LUS detected ILD in 51 patients. Four patients with negative LUS findings were positive on HRCT. The results showed 93% sensitivity, 73% specificity, 3.40 PLR, 0.10 NLR, 94% PPV, and 67% NPV for LUS, whereas 100% sensitivity, 82% specificity, 5.49 PLR, 0.01 NLR, 97% PPV, and 100% NPV for HRCT. Comparison of the 2 ROC curves revealed significant difference in the diagnostic value of the 2 methods for the diagnosis of ILD (P = .048). Our results indicated that LUS is a useful technique to identify ILD. Considering its non-radiation, portable and non-invasive advantages, LUS should be recommended as a valuable screening tool in patients with suspected ILD.