We investigated whether the spine sign would help family physicians diagnose left lower lobe pneumonia on chest radiographs.
Among patients with pneumonia, the lateral view was helpful when the spine sign was present, but it was misleading when the spine sign was absent.
Among pneumonia patients with the spine sign, however, the lateral view was often helpful.
The purpose of this study was to determine the usefulness of the lateral projection and the usefulness of the spine sign to family physicians who interpret chest radiographs with left lower lobe pneumonia.
At the beginning of the study, a different faculty radiologist ("second radiologist"), who was blinded to the original readings, repeated the interpretations and judged whether the spine sign was present.
13-15] In addition, each reader was asked to state whether the spine sign was present.
The six family physician readers reported presence of the spine sign slightly more often than the radiologist (mean, 72.
We repeated the analysis after including only pneumonia patients who had the spine sign (n=43) and all normal patients (n=83).
Therefore, when reading chest radiographs with left lower lobe pneumonia, the physicians tended to benefit from the lateral view when the spine sign was present, but they were often misled by the lateral view when the spine sign was absent.
In most pneumonia patients with helpful lateral views, the pneumonia was retrocardiac on the PA view, and a classic spine sign was seen on the lateral view (Figure 2).
At the beginning of each reading session, we showed examples of the spine sign and a normal lateral chest view to the readers.