Table 3.

Inter-Reader Concordance for MRI.

Feature	Reader 1		Reader 2		Number Concordant (%) +		Kappa
	Inter-modality subset+	All MRI++	Inter-modality subset+	All MRI++	Inter-modality subset+	All MRI++	Inter-modality subset	All MRI
Opacity Present	84/88	338/424	77/88	320/424	79/88 (89.8)	360/424	0.36	0.57
	(95.5)	(79.7)	(87.5)	(75.5)		(84.9)
Opacity Extent					38/88 (43.2)	202/424	0.38	0.32
0—no opacity	4	86	11	104		(47.6)
1— <25 %	32	163	26	121
2–25 - <50 %	31	105	24	72
3–50 - <75 %	15	51	17	86
4— >75 %	6	19	10	41
Opacity Distribution					73/88 (83)	296/424	0.55	0.46
None	4	82	9	103		(69.8)
Peripheral	16	91	10	51
Central and	67	243	69	269
Peripheral Central	1	8	0	1
Subpleural Lines	17	41	19	85	80/88 (90.9)	366/424 (86.3)	0.72	0.47
Subpleural Reticulation	52	125	47	94	57/88 (64.8)	321/424 (75.7)	0.29	0.37

⁺Denominator is 88, corresponding to number of lung quadrants scored by each reader, in the 22 exams used for inter-modality assessment.

⁺⁺Denominator is 424, corresponding to number of lung quadrant scored by each reader, in all 106 low-field MRI exams.