Transthoracic ultrasound in the evaluation of pulmonary fibrosis: our experience.

The purpose of this study was to identify the ultrasonographic features of mild, moderate and severe pulmonary fibrosis. Between December 2005 and November 2007, transthoracic ultrasonography (US) was performed by a single operator with specific training in lung sonography on 84 consecutive patients (51 males and 33 females, aged 46 to 73 y) with pulmonary fibrosis. The obtained data were compared with those from a sample of 162 healthy subjects (78 men and 84 women, aged 18 to 76 y). The disease was idiopathic (biopsy confirmed) in 53/84 cases (63%). In the remaining (all histologically confirmed) cases, it was associated with systemic sclerosis (n = 18), rheumatoid arthritis (n = 4), mixed connective tissue disease (n = 4), Sjogren syndrome (n = 4), polymyositis (n = 2) or primary biliary cirrhosis (n = 1). Disease severity was classified as mild, moderate or severe based on clinical findings and the results of standard chest radiography, high-resolution computed tomography and pulmonary function tests. Pulmonary fibrosis was associated with the following US findings: (1) fragmented, irregular thickening (micro3 mm) of the "pleural line" distributed over the whole surface of the lung, especially in the lower posterior lobe (observed in all 84 patients); (2) subpleural cysts (seen in 57/84 (68%) cases of moderate-severe disease); (3) reduction or absence of the physiological "gliding sign" related to disease severity (observed in 33/84 to 39% cases); and (4) increased number of horizontal (and to a lesser extent vertical) reverberation artifacts (seen in 41 patients with advanced fibrosis, 34% of the total series). All abnormalities were detected in both lungs. Although lung biopsy is still the gold standard for diagnosis of interstitial lung disease, transthoracic ultrasound can document early and late-stage changes associated with this disease.