PURPOSE: The differential diagnosis of chronic obstructive pulmonary disease (COPD) and asthma requires careful history taking and physical exam. The bronchodilator reversibility test aids in distinguishing COPD from asthma. Recognizing that some patients with asthma show poor reversibility and some COPD patients show significant reversibility, a bronchodilator response measured by improved spirometry, favors the diagnosis of asthma and absence of response favors the diagnosis of COPD. We assessed whether the vibration response imaging (VRI™) technology can detect an increase in forced expiratory volume in 1 second (FEV1).
METHODS: 38 patients (19F, age 57±11yrs), diagnosed with asthma (8), with COPD (21) and with suspected pulmonary obstruction (9) were recorded by the VRIXP™ device before and after bronchodilator PFT. Post-bronchodilator images were compared to pre-bronchodilator images and were blindly graded for quality, improved or not improved for shape, size, intensity, dynamic appearance or breathing waveform. For the purposes of this study, we defined FEV1 change as an increase or a decrease of at least 5% (taking in account possible error in measurement). The agreement/accuracy between VRI™ technology and FEV1 results was assessed.
RESULTS: The agreement between VRI™ technology and FEV1 increase/no increase was 76% (29/38). In cases that had an in increase in FEV1 the accuracy rate was 84% (21/25). In cases that FEV1 did not increase the accuracy rate was 62% (8/13). The agreement between VRI™ technology and FEV1 increase/no increase in asthma patients was 88% (7/8), in COPD patients was 71% (15/21) in patients with suspected obstruction was 78% (7/9).
CONCLUSION: The VRI™ technology is able to detect a small increase/no increase in FEV1 in patients treated with bronchodilators.
CLINICAL IMPLICATIONS: Use of additional information provided by the imaging of lung sounds may improve the differential diagnosis of COPD and asthma. Together with spirometry results, the VRI™ technology may improve diagnoses of obstructive diseases. Additional patients and tests are necessary to confirm this preliminary analysis.
DISCLOSURE: Kalpalatha Guntupalli, No Product/Research Disclosure Information; Grant monies (from industry related sources) Study was supposted by Deep BreezeTM