COMPARATIVE FINDINGS OF DIGITAL CHEST IMA GES AND DIGITAL IMAGES A PHANTOM REVIEWED WITH FILM, A RADIOLOGICAL WORK STATION AND A PC

Introduction: An ROC analysis was carried out in order to determine th e reliability of digital luminescence radiography review at a PC and t his was compared with a radiological work station and with X-ray film on a viewing box. Material and method: 54 chest images obtained by dig ital luminescence radiography were selected, 31 of these contained sma ll pulmonary nodules. In order to evaluate critical detail, five image s of a phantom showing round foci were used. Five radiologists examine d these, using a Siemens Magic View work station, a PC with proprietar y software (ViewMed) and X-ray films on a viewing box. Image processin g of the work station used the standard clinical application. ViewMed performs linear scaling of grey levels to 8 Bit. The results were exam ined statistically by means of a t-test. Results: As far as the chest images were concerned there was no significant difference in the diagn ostic value of these methods. There was, however, a highly significant loss of diagnostic information with respect to the round focus phanto m when using the PC compared with the other methods. Conclusion: In th e configuration in which it was used, the PC should not be relied on a s a primary means of examination since critical details cannot always be seen. In routine use these play a subordinate role and there was no significant diagnostic loss where the chest images were concerned. We expect that by improvements in the frequency and contrast processing the PC accuracy will be considerably increased.