Broken-fat pad sign: a characteristic radiographic finding to distinguish between knee rheumatoid arthritis and osteoarthritis

Insights into Imaging

Table 2 Diagnostic performance of radiologists and evaluation process

	TP	FP	FN	TN	Accuracy (%)	Sensitivity (%)	Specificity (%)	AUC	SE	95% CI
Reader1
Initial diagnosis	42	29	39	52	58.02	51.85	64.20	0.58	0.039	0.50–0.66
Sign evaluation	52	20	29	61	69.75	64.20	75.31	0.70	0.036	0.62–0.77
Final diagnosis	60	18	21	63	75.93	74.07	77.78	0.76	0.034	0.69–0.82
Reader2
Initial diagnosis	53	16	28	65	72.84	65.43	80.25	0.73	0.035	0.65–0.80
Sign evaluation	59	17	22	64	75.93	72.84	79.01	0.76	0.034	0.69–0.82
Final diagnosis	64	16	17	65	79.63	79.01	80.25	0.80	0.032	0.73–0.86

TP, True-positive, FN False-negative, TN True-negative, FP False-positive, AUC Area under the curve, SE Standard error, CI Confidence interval