Comparison Of Digital Radiography And Conventional X-ray In The Diagnosis Of Solitary Pulmonary Nodules With Receiver Operating Characteristic Curves Analysis

Chest radiography has an important role in the diagnosis of chest diseases. Invention of digital radiography had provided new developmental chance for the ancient object. Digital chest radiography offers two main groups of advantages:those related to imagine processing and those related to digital storage and transmission. Its disadvantages are related to display size that is less than life size and the visibility of noise.There are two purposes of this study .The first is to compare digital radiography with conventional radiography in the detection of solitary pulmonary nodules and the second is to study the sectional anatomy as well as chest computed tomography (CT) image of the location in the lung where pulmonary nodules often be missed. Thirty patients with solitary pulmonary nodule and 30 cases without pulmonary nodules enrolled in the study. The existence of solitary pulmonary nodule was confirmed by chest computed tomography (CT) and biopsy. All patients were examined by both digital radiography (group A) and conventional radiography (group B) were reviewed by four experienced chest radiologists and four residents. Assessment was performed with receiver operating characteristic (ROC) analysis of the images in both groups. The images of digital radiography were assessed by using a picture archiving and communication system viewer with a 1,280x 1,024-pixelmonitor(SONY CPD-G420) .Three locations were selected from upper results where pulmonary lung nodules were most likely to bemissed and the sectional anatomy as well as chest computed tomography (CT) were studied so as to analyze the reasons. At last, some advices were given.Some Results are below:1. observer performance of the experienced radiologists in group B (Az=0. 838) was superior to that in group A (Az=0. 816) (P<0. 05) in the detection of solitary pulmonary nodule. For the residents, observer performance in group B (Az=0.842) was superior to that in group A (Az=0.712) (P<0.05).2. For the judgment of benign or malignant to the solitary pulmonary nodule, there was no difference between the two groups (P=0. 272).3. Three sites were selected where pulmonary nodules often be missed including medial belt of upper lung zone, left lower lung zone overlapping the heart and medial belt of right lower lung zone which are often obscured by many anatomic structures , so we should take advantage of the digital radiography and make full use of lateral projection technical oblique projection technical so as to minimize the failing of detection of pulmonary lung nodules. By the way, care is needed in the detection.Conclusions :1. Digital radiography is superior to conventional radiography in detection of solitary pulmonary nodule;2. There was no significant differences between the two groups in judgment whether the solitary pulmonary nodules was benign or malignant.3. It is important to take advantage of digital radiography and make full use of other kinds of X-ray projection techniques in the detection of pulmonary lung nodules.