Table 2.

Distribution of erosions in different region of interest according to CT and US, and sensitivity, specificity, accuracy and k values for high-resolution US in detecting erosion (grading from 0 to 3) at different joint sites using CT as the reference method

	Quadrants	CT-detected erosions	US-detected erosions	Sensitivity (%)	Specificity (%)	Exact agreement (%)	k values (95 % CI)
Second metacarpal head	156	27 (17.3)	21 (13.5)	51.9	95.3	87.8	0.63 (0.43 to 0.83)
Dorsal	52	16 (30.8)	13 (25.0)	56.3	88.9	78.8	0.51 (0.26 to 0.75)
Lateral	52	11 (21.2)	8 (15.4)	54.5	95.1	86.5	0.77 (0.54 to 1.00)
Volar	52	0	0	NC	NC	NC	NC
Third metacarpal head	104	15 (14.4)	4 (3.8)	20.0	98.9	87.5	0.26 (0.03 to 0.48)
Dorsal	52	14 (21.2)	4 (15.4)	21.4	97.4	76.9	0.24 (0.02 to 0.46)
Volar	52	1 (1.9)	0	0	100	98.1	0 (0.00 to 0.00)
Fourth metacarpal head	104	7 (6.7)	1 (0.9)	14.3	100	94.2	0.19 (-0.12 to 0.51)
Dorsal	52	6 (11.5)	1 (1.9)	17.0	100	90.4	0.08 (-0.09 to 0.26)
Volar	52	1 (1.9)	0	0	100	98.1	0 (0.00 to 0.00)
Fifth metacarpal head	156	8 (5.1)	6 (3.8)	50.0	100	96.3	0.77 (0.66 to 0.89)
Dorsal	52	6 (11.5)	4 (7.7)	66.7	100	96.2	0.73 (0.56 to 0.90)
Lateral	52	2 (3.8)	2 (3.8)	100	100	100	0.85 (0.74 to 0.97)
Volar	52	0	0	NC	NC	NC	NC
Radiocarpal	104	18 (17.3)	6 (5.8)	33.0	100	88.5	0.57 (0.30 to 0.83)
Dorsal	52	15 (28.8)	4 (7.7)	26.7	100	78.8	0.48 (0.16 to 0.80)
Lateral	52	3 (5.7)	2 (3.8)	66.7	100	98.1	0.79 (0.39 to 1.0)
Ulnar head	104	17 (16.3)	5 (4.8)	23.5	98.9	86.5	0.29 (0.05 to 0.54)
Dorsal	52	13 (25.0)	4 (7.7)	23.1	97.4	78.8	0.23 (-0.03 to 0.50)
Lateral	52	4 (7.7)	1 (1.9)	25.0	100	94.2	0.38 (-0.15 to 0.91)
Total	728	92 (12.6)	43 (5.9)	35.9	98.7	90.8	0.50 (0.36 to 0.63)

Unless otherwise specified, values are the number of patients (values in brackets are percentage). CT computed tomography, US ultrasound, NC not computable