Diagnosis of Gastric Cancers: Comparison of Conventional Radiography and Digital Radiography with a 4 Million-Pixel Charge-coupled Device

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Abstract
To evaluate the differences in accuracy and observer performance at conventional radiography and at digital radiography with a 4 million-pixel charge-coupled device (CCD) for the diagnosis of gastric cancers. A prospective study was performed of 225 patients with suspected gastric cancer who were referred to our hospital from January 1997 through February 1997. One hundred twelve patients were examined at conventional radiography and 113 were examined at digital radiography, and 24 and 27 patients had gastric cancer, respectively. Six radiologists interpreted the images, with attention to tumor findings. They were blinded to the clinical details, and their interpretations were rated against those of three other radiologists who examined the patients and who were aware of the clinical information such as endoscopic features and/or histopathologic findings in biopsy specimens. Receiver operating characteristic (ROC) analysis was used to compare the differences in observer performance for the diagnosis of gastric cancers at conventional radiography and at digital radiography. The overall sensitivity was 64.6% at conventional radiography versus 75.3% at digital radiography (P =. 287); specificities were 84.5% and 90.5%, respectively (P =.011); and the positive predictive values were 53.1% and 71.3%, respectively (P =.036). ROC analysis clearly showed higher diagnostic performance at digital radiography than at conventional radiography. The data demonstrate the high diagnostic value of digital radiography with a 4 million-pixel CCD for gastric cancers. The technique has considerable potential as an alternative to conventional gastrointestinal radiography.