PURPOSE: The Vibration Response Imaging (VRI) device records lung vibrations during respiration from 40 sensors positioned over the posterior chest wall. The VRI device presents recorded information in a quantitative and qualitative manner. Vibration energy is calculated and can be displayed as total lung vibration signal or measured regionally. Thus, analysis of vibration energy enables relative regional assessment (RRA) of ventilation. The reproducibility of the VRI RRA in normal individuals was evaluated.
METHODS: The VRI images of 29 normal subjects (average ± SD age: 29 years ± 2 years, 75% male) were recorded. Subjects were defined as normal according to medical history and physical exam. Subjects underwent 3 VRI recordings on 3 separate days at least twenty four hours apart. The RRA was calculated for each VRI recording and the RRA of the 3 different recordings compared.
RESULTS: The RRA evaluations of left and right lung from the 3 recordings correlated well. The average ±SD RRA of the left lung of the 3 different recordings (56%±5%, 56%±6% and 55%±6%) did not significantly differ (p>0.05, ANOVA). Right lung results were analogous to left lung results. The average±SD Absolute Relative Error (ARE) was 4%±2%, 95% confidence interval (CI) was 3% to 5%. Furthermore, the RRA evaluations of the upper, middle and lower regions did not significantly differ (p> 0.05, ANOVA). The average ± SD ARE of the upper middle and lower regions was 10%±6%, 95%CI was 9% to 11%.
CONCLUSION: RRA offers a non-invasive method for assessing regional variation in ventilation. We have demonstrated that the VRI quantification of lung RRA is reproducible in normal subjects.
CLINICAL IMPLICATIONS: The VRI device provides the potential to be an invaluable consulting room tool for aiding clinicians in diagnosing, assessing and managing pulmonary disease.
DISCLOSURE: Duncan Geddes, Grant monies (from industry related sources) Deep Breeze Ltd.