Comparison of plain radiographs and computed tomographic scanning in nasopharyngeal carcinoma

Plain radiographs, computed tomographic (CT) scans and clinical records of 100 patients with nasopharyngeal carcinoma were studied. CT scans and plain radiographs provided similar information in 46 patients. There were 54 cases in which the two techniques disagreed. In 45 cases CT demonstrated abnormalities not seen in plain radiographs and in nine cases plain radiographs demonstrated abnormalities not seen with CT scanning. Based on the total information gained from clinical examination, the imaging investigations, biopsies, and subsequent clinical course and investigations it appeared that none of the abnormalities predicted by plain radiographs alone could be substantiated. Conversely the CT abnormalities could be supported as being correct. We conclude that CT alone is the undoubted investigation of choice where this is available. Plain films provide less information, are unreliable and, where CT is available, superfluous.