Evaluation of the different resolution of grayscale display over the detection efficiency of pulmonary nodule / 中华放射学杂志

ABSTRACT

Objective To evaluate the influence of the resolution of medical grayscale LCD over the detective efficiency of pulmonary nodule.Methods By reviewing PACS, 93 on-line chest DR images were collected.These radiographs included 23 normal images that had no nodule confirmed by CT, 32 doubtful images that also had no nodule confirmed by CT,and 38 positive images that had nodules confirmed by CT.These nodules didn't show obvious calcification and their diameters were from 0.30 to 1.90 cm. Nine patients had multi-nodules.Three residents or postgraduates, three attending physicians, and three associate professors or professors interpreted the 93 chest images by using three types of displays: Barco Z-2261, Barco Z-3620 and Barco Z-5620.All observers evaluated their confidence of the presence of pulmonary nodule with five-point level rating scale : ( 1 ) definitely positive, ( 2 ) probably positive, ( 3 ) uncertain, (4) probably negative, (5)definitely negative.SPSS 11.5 software was used to analyze the results ,including to draw the ROC curves and to perform Z test.Results The areas under the ROC curves of 2 M display, 3 M display and 5 M display were 0.774,0.784,0.816 for experienced radiologists; for instructors were 0.754,0.764,0.768 ;for teaching assistants were 0.695,0.754,0.774.However, for the detection of pulmonary nodules,there was no significant difference between observers with different ranks using the same modality of display,and no significant difference was found between the different modalities of displays used by observers with the same rank.Conclusion It's equivalent for detection performance with 2,3 and 5 M medical grayscale LCD display in detecting pulmonary nodule; Experienced radiologists can get more information using 5 M display;By reasonably matching displays, we could improve the cost-efficacy.