CHEST RADIOGRAPHS AS A SCREENING-TEST FOR DIFFUSE IDIOPATHIC SKELETALHYPEROSTOSIS

Objective. To evaluate the sensitivity, specificity, predictive value, interrater reliability of using chest radiographs as a screening tool for the diagnosis of diffuse idiopathic skeletal hyperostosis (DISH). Methods. After review of thoracic spine radiographs by 2 ''gold stand ard'' physicians, 45 patients with DISH meeting the criteria of Resnic k and Niwayama were contrasted with 106 control patients consisting of 45 with thoracic spondylosis, 45 who lacked spondylosis and whose tho racic spine radiographs were otherwise normal for the age of the patie nt, and 16 with ankylosing spondylitis. The chest radiographs on the 1 51 subjects were placed in random order and read independently using a n ordinal diagnostic certainty scale by 2 ''test'' radiologists, exper ienced in reading bone radiographs. Two months later the order of ches t radiographs was rerandomized and the films reassessed by the same te st radiologists. Results. The averages for the diagnostic and populati on test characteristics were sensitivity = 77%; specificity = 97%; pos itive predictive value = 91%; and, negative predictive value = 91%. Th e area under the receiver operating characteristic curves was 0.975 an d 0.976 for the radiologists, and kappa was 0.93, demonstrating that i nterrater reliability was high. On rereading the chest radiographs, in trarater reliability was exceptional (weighted kappa of 0.90 and 0.96 for the two test radiologists). DISH patients whose chest radiographs were read as not demonstrating DISH had significantly less extensive d isease. Conclusions. We conclude that chest radiographs are a reliable and valid screening tool for the diagnosis of DISH.