DIRECT DIGITAL RADIOGRAPHY FOR THE DETECTION OF PERIAPICAL BONE-LESIONS - A CLINICAL-STUDY

The aim was to compare the observer performance of direct digital radi ography, with and without image processing, with that of conventional radiography, for the detection of periapical bone lesions. For 50 pati ents, a conventional periapical radiograph using E-speed film was take n. Then, a direct digital image of the same area was made. The images presenting the periapical bone tissue of 59 roots were assessed by sev en observers using a 5-point confidence scale. The digital images were first presented as original images, with default contrast and brightn ess set by the computer system. Following this, the observers were all owed to use the processing facilities for greyscale treatment. The res ults for original and processed direct digital images and for conventi onal radiographs were compared by Receiver Operating Characteristic (R OC) analysis. The area under the ROC curve, calculated as P(A) value, was 0.88 for conventional film, 0.82 for original digital images and 0 .78 for processed images. Corresponding A(z) values were slightly high er, 0.89, 0.84 and 0.81. Statistically significant differences between ROC areas calculated as P(A) values for the methods were found. Compa rison between A(z) values showed no significant differences between co nventional radiographs and original digital images, whereas the differ ence between A(z) values for original and processed digital images was still significant. It was concluded that conventional film radiograph y performed slightly better for the detection of periapical bone lesio ns than direct digital radiography and that image processing did not i mprove the observer performance.