BACKGROUNDAlthough chest radiography is a useful examination tool, it has limitations. Because not all chest conditions can be detected on a radiograph, radiography cannot necessarily rule out all irregularities in the chest. Therefore, further imaging studies may be required to clarify the results of a chest radiograph, or to identify abnormalities that are not readily visible. The aim of this study was to compare traditional chest radiography with acoustic-based imaging (vibration response imaging) for the detection of lung abnormalities in patients with acute dyspnea.

METHODSThe current investigation was a pilot study. Respiratory sounds throughout the respiratory cycle were captured using an acoustic-based imaging technique. Consecutive patients who presented to the emergency department with acute dyspnea and a normal chest radiograph on admission were enrolled and underwent imaging at the time of presentation. Dynamic and static images of vibration (breath sounds) and a dynamic image score were generated, and assessments were made using an evaluation form.

RESULTSIn healthy volunteer controls (n = 61), the mean dynamic image score was 6.3 ± 1.9. In dyspneic patients with normal chest radiographs (n = 51) and abnormal chest radiographs (n = 48), the dynamic image scores were 4.7 ± 2.7 and 5.1 ± 2.5, respectively (P < 0.05). The final assessment of the vibration images indicated abnormal findings in 15%, 86% and 90% of the participants in the above groups, respectively (P < 0.05).

CONCLUSIONSIn patients with acute dyspnea who present with normal chest radiographs, respiratory sound analyses often showed abnormal values. Hence, the ability of acoustic-based recordings to offer objective and noninvasive measurements of abnormal sound transmission may be useful in the clinical setting for patients presenting with acute dyspnea.