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. Author manuscript; available in PMC: 2014 Mar 1.
Published in final edited form as: Osteoarthritis Cartilage. 2012 Dec 28;21(3):413–418. doi: 10.1016/j.joca.2012.12.006

Table 2.

Sensitivity, specificity, accuracy of signal changes in Hoffa’s fat pad on non-contrast-enhanced MRI (proton density-weighted fat-suppressed), considering synovial thickness measurements on contrast-enhanced MRI as the reference standard.

INFRAPATELLAR
Synovial thickness
on contrast-
enhanced MRI
(reference) 		Signal changes in HFP on non-
contrast-enhanced MRI (test) 		Sensitivity
(95% CI) 		71%
(60%. 81%)
Grade 0
(normal)		 Grades 1–3
(abnormal)		 Total Specificity
(95% CI) 		55%
(49%. 60%)
Grade 0 (normal) 174
(TN)		 143
(FP)		 317
Grade ≥ 1
(abnormal)		 22
(FN)		 54
(TP)		 76 Accuracy
(95% CI) 		58%
(53%. 63%)
INTERCONDYLAR
Synovial thickness
on contrast-
enhanced MRI
(reference) 		Signal changes in HFP on non-
contrast-enhanced MRI (test) 		Sensitivity
(95% CI) 		88%
(79%. 95%)
Grade 0
(normal)		 Grades 1–3
(abnormal)		 Total Specificity
(95% CI) 		30%
(25%. 35%)
Grade 0 (normal) 93
(TN)		 222
(FP)		 315
Grade ≥ 1
(abnormal)		 9
(FN)		 69
(TP)		 78 Accuracy
(95% CI) 		41%
(36%. 46%)

HFP= Hoffa’s fat pad. TN = true negatives; FN = false negatives; FP = false positives; TP = true positives; CI = confidence intervals; Sensitivity = TP/TP+FN; Specificity = TN/TN+FP; Accuracy = TP+TN/TP+FP+FN+TN