[Evaluation of the display quality of different modalities in digital radiology]

To evaluate the display quality of digital radiographies on different monitors in comparison to hard-copy films on view boxes.

Radiographs of different statistical phantoms simulating common pathologies of the chest, such as interstitial pneumonia, pneumothorax and pulmonary nodules, were acquired. Under same ambient light condition, the radiographs were rated as to the presence or absence of a simulated pathological finding using a confidence scale. The evaluation was performed on a grey-scale monitor, a color monitor, two LC displays and two different light boxes by four experienced radiologists. Sensitivity and specificity were determined in a ROC analysis for each viewing modality and phantom. The area under the curve (Az) was acquired cumulatively including the results of all investigators. A total of 4200 rating decisions were included. The chi (2)-test was performed for significance analysis using the a and b parameters of two ROC-curves (alpha = 0.05).

The rating of the included LC displays (Az = 0.7009 - 0.9608) and color monitors (Az = 0.7993 - 0.9591) showed a significant loss of diagnostic validity in comparison to the grey-scale monitor (Az = 0.8435 - 0.9762) and the view boxes (Az = 0.8228 - 0.9891).

LC displays and color monitor included in this study cannot be recommended for diagnostic viewing. The loss of diagnostic validity might be attributable to the viewing-angle-dependent contrast of LC displays. However, no loss in diagnostic validity could be assessed for the tested grey-scale monitor.