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.