Vibration response imaging of the lungs in mechanically ventilated patients in chronic obstructive pulmonary disease
© Biomed central limited 2001
Published: 21 March 2006
Vibration response imaging (VRI) measures the vibration response energy generated from airflow to create a radiation-free, dynamic, real-time, structural and functional image of the respiration process. The characteristics of VRI in mechanically ventilated patients with chronic obstructive pulmonary disease (COPD) has not been previously studied.
This was an observational study to compare the VRI of mechanically ventilated (MV) patients with no known pulmonary disease with those with COPD.
Five consecutive MV patients with COPD were compared with five consecutive MV patients with no known pulmonary disease. Using custom-designed software the vibration signals were fitted to a mathematical function and a gray level frame was constructed. At peak inspiration and expiration, spatial areas of the images were captured and the total area of the image calculated using ImageJ Software.
Distribution of image area in patients with no pulmonary disease
Distribution of image area in patients with COPD
The increase in the image area during the expiratory phase in COPD patients may reflect increased airflow resistance causing increased vibration energy. Air trapping and auto-PEEP are other possible mechanisms accounting for the expiratory increase in image area.
VRI provides real-time non-invasive lung imaging of airflow in the mechanically ventilated patient. Mechanically ventilated COPD patients demonstrate a dramatically different VRI pattern than normal MV patients. VRI may provide important diagnostic information in COPD patients.