Assessment of ultrasound acoustic artifacts in patients with acute dyspnea: a multicenter study.

BACKGROUND: Recent reports indicate that numerical assessment of B-lines during transthoracic ultrasound may aid the differential diagnosis of acute diffuse pleuropulmonary disorders. PURPOSE: To determine whether B-lines are different in normal and diseased lungs and whether they can be used to discriminate between different types of pulmonary disorders in acutely ill patients. MATERIAL AND METHODS: In this multicenter study, transthoracic ultrasonography was performed on 193 patients with acute dyspnea, 193 healthy non-smokers, and 58 patients who had undergone pneumonectomy for lung cancer. Examinations were done with a low-medium frequency (3.5-5.0 MHz) convex probe and a high-frequency (8-12.5 MHz) linear probe. Video recordings were re-examined by a second set of examiners. In each participant, we measured the number of B-lines observed per scan. RESULTS: B-lines counts were higher in dyspnoic patients (means: 3.11 per scan per linear probe scan vs. 1.93 in healthy controls and 1.86 in pneumonectomized patients; P < 0.001 for all); all counts were higher when convex probes were used (5.4 in dyspnoic patients and 2 in healthy controls; P < 0.001 vs. the linear probe). Subgroups of dyspnoic patients defined by cause of dyspnea displayed no significant differences in the number of B-lines. CONCLUSION: Our results demonstrate that there are a significant higher number of B-lines in the lungs of patients with dyspnea compared to healthy subjects and to pneumonectomized patients. Nevertheless, the quantification of B-lines does not make any significant contribution to the differential diagnosis of dyspnea.

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.