Portable chest imaging: comparison of storage phosphor digital, asymmetric screen-film, and conventional screen-film systems.

The quality of chest images obtained with portable radiography was evaluated for a conventional screen-film system, a new asymmetric screen-film chest system, and computed radiography (CR). Sixty chest images were obtained in 20 patients in an intensive care unit. The CR system was ranked by all three evaluating radiologists as substantially better in overall diagnostic quality, interpretability of the lungs, and musculoskeletal detail and by two of the three observers as better for the visibility of catheters and lines. In the upper abdomen and mediastinum, there was not a clear preference. Standard deviations of film density were +/- 0.12, +/- 0.41, and +/- 0.39 for the CR, conventional, and asymmetric systems, respectively. For the same systems, phantom results indicated the relative lung contrast values were 1.2, 1.0, and 0.89, respectively. Similarly, the limiting resolution values in the lung were 2.0, 4.2, and 6.3 line pairs per millimeter. The CR system had twice the root-mean-square noise of the screen-film systems. Overall, the preferred system for portable chest imaging was the CR system.