PURPOSE: Vibration response imaging (VRI) is a novel dynamic imaging technique that measures vibration energy of lung sounds. The purpose of this study is to determine if VRI is useful in tracking therapeutic response in acute heart failure patients.
METHODS: We performed VRI on 7 consecutive acute heart failure (AHF) patients on admission to emergency department (ED) and 2–11 days later prior to hospital discharge (following clinical and chest radiographic improvement). Inclusion criteria for analysis was history and risk factors plus chest radiographic diagnosis of AHF. Four to twelve expiratory cycles free of noise or artifacts were chosen and images were analyzed at maximum inspiratory vibration energy. Areas of both lungs were calculated digitally using the program Image J. In addition the average of the maximal inspiratory vibration energy from the chosen cycles, expressed as vibration units (VU) was analyzed. Statistical analysis was performed using t-test.
RESULTS: The total mean areas of both lungs were 59174 ± 6391 pixels and 73385± 5602 pixels (mean±SD) in AHF patients before and after therapy, respectively (p = 0.01). The mean vibration energy of both lungs were 6553270 ± 4861595 VU and 984069± 934172 VU (mean ±SD) in AHF patient before and after therapy, respectively (p = 0.02).
CONCLUSION: There was an increase in the areas of the VRI images and a decrease in vibration energy at maximal inspiration energy following therapy for AHF.
CLINICAL IMPLICATIONS: Because the VRI image is normalized (black referred to highest energy area and white to a pre-defined minimum), increase in size of image is by definition more homogeneous distribution of vibration. Acute pulmonary edema appears to increase lung vibration. Treatment of pulmonary edema is associated with decreased vibration and greater VRI area, the later likely related to a more even distribution of vibration. VRI may be useful in tracking therapeutic response in acute heart failure patients.
DISCLOSURE: Zhen Wang, No Financial Disclosure Information; No Product/Research Disclosure Information