Ovarian cancer: Comparison of observer performance for four methods of interpreting CT scans

PURPOSE: To assess the effects or four interpretative methods on observers' mean sensitivity and specificity by using computed tomography (CT) of ovar ian carcinoma as a model. MATERIALS AND METHODS: CT scans in 98 patients with ovarian carcinoma and 4 9 women who were disease free were retrospectively reviewed by four experie nced blinded radiologists to compare single-observer reading, single-observ er reading with an anatomic checklist, paired-observer reading (simultaneou s double reading), and replicated reading (combination of two independent r eadings). Confidence level scoring was used to identify three possible dise ase forms in each patient: extranodal tumor, lymphadenopathy, and ascites. Patient conditions were then categorized as abnormal or normal. RESULTS: There were no significant improvements in sensitivity or specifici ty for classification of patient conditions as abnormal or normal when comp aring single-observer interpretation with single-observer interpretation wi th a checklist or paired-observer interpretation. Although there was no sig nificant improvement in the mean sensitivity (93% vs 94%) by using the repl icated reading method, there was a statistically significant improvement in mean specificity (85% vs 79%) for the replicated readings compared with si ngle-observer interpretations (P < .05). CONCLUSION: Diagnostic aids such as checklists and paired simultaneous read ings did not lead to an improved mean observer performance for experienced readers. :However, an increase in the mean specificity occurred with replic ated readings.