Detectability of the Mediastinal Lines: Comparison of Conventional Film-Screen Radiography and DigitalRadiography

Shin, Hye Young; Park, Kyung Joo; Kang, Doo Kyung; Lee, Kang Lai; Han, Chang Jin; Suh, Jung Ho

Abstract

PURPOSE: Using dynamic range compression (DRC) processing, this study compared the detectability ofmediastinal lines by conventional film screen rediography (FS) and by storage phosphor digital radiography(DR).
MATERIALS AND METHODS
We selected 200 normal consecutive chest radiographs (100 FS, 100 DR) ; dynamic rangecompression was applied to DR processing and moving grids were used in both systems. Seven mediastinal lines (leftfaraspinal, right paraspinal, azygoesophageal, left para-aortic, posterior junctional, anterior junctional andright paratracheal) were scored from 0 point to 3 point(0:not visible, 1:suspiciously visible, 2:visible, but notclear, 3: clearly visible) according to visibility and sharpness, as agreed by a radiologist and a resident. Thedifferences between the two modalities were compared and analyzed by chi-square test.
RESULTS
Among the 1400mediastinal lines analyzed, 419 lines by DR(59.9%) and 232 lines by FS(33.1%) were scored more than 2 points. Inall mediastinal lines except the left para-aortic, DR was more detectable and clearer than FS, with statisticalsignificance(P<.01).
CONCLUSION
DR processed with DRC visualizes mediastinal lines more frequently and clearlythan conventional FS, and is therefore thought to be useful for the evaluation of mediastinal diseases.