Figure 1. Example of a “normal” maximum energy frame—a static acoustic image equating to the period of maximal sound energy during inspiration. High intensity vibration energy is depicted in dark grey through to black. Low intensity vibration energy shows as grey and absence of vibrations as white. The graph beneath the image plots average vibration energy (first peak is maximal inspiratory energy, second peak represents maximal expiratory energy) as a function of time. The image shows smooth symmetrical lung contours with a near symmetrical distribution of acoustic lung energy. L, left; R, right.