Table 1.

Interobserver agreement for single US features, compared with published data.

	This study		Choi, 2010 (22)a	Kim, 2012 (23)	Kim, 2010 (24)a			Koltin, 2016 (25)	Lim-Dunham, 2017 (26)	Norlen, 2014 (32)b	Park, 2009 (27)	Park, 2010 (28)	Park, 2012 (29)	Wienke, 2003 (30)	Grani, 2017 (31)
Nodules	Set 1: 501	Set 2: 554	204	80	133			27 (pediatric pop.)	39 (pediatric population)	141 (AUS/FLUS)	52 (all malignant)	133	400	70	49 (AUS/FLUS/FN)
Statistics	Krippendorff alpha		Kappa	Kappa	Kappa			Kappa	Kappa	Kappa	Spearman corr.	Kappa	Kappa	Kappa	Krippendorff alpha
Observers	2 clinicians, same level of experience		4 exp. radiologists, same institution	7 resident radiologists, 2 different units	9	5 faculty radiologists	4 residents	3 exp. radiologists	2 exp. radiologists	2 trained surgeons	3 radiologists (1–7 year exp.)	5 radiologists (1-–6 6year exp.)	3 radiologists (7-–10 10year exp.), different institution	2 radiologists	3 clinicians, 2 different units
Echogenicity	0.56 (0.46-–0.66)	0.66 (0.59-–0.73)	0.45	0.5	0.46	0.57	0.34	0.46	0.54 (0.37-–0.73)	0.94	0.04–0.45	0.57	0.504	0.37	0.58 (0.45–0.70)
Composition	0.52 (0.34–0.68)	0.5 (0.29–0.68)	0.59	0.48	0.36	0.64	0.18	N/A	0.8 (0.53–0.99)	N/A	0.70–1.00	0.64	0.818	0.62	0.5 (0.29–0.68)
Shape	N/A	N/A	0.61	0.57	0.4	0.46	0.34	N/A	0.29 (0.01–0.72)	0.61	0.48–0.79	0.42	0.42	N/A	N/A
Margin	0.51 (0.43–0.58)	0.44 (0.34–0.53)	0.61	0.49	0.25	0.4	0.19	0.58	0.6 (0.4–0.79)	0.6	0.03–0.29	0.34	0.33	0.13	0.57 (0.43–0.70)
Vascularity	N/A	N/A	0.46	N/A	N/A	N/A	N/A	0.18	0.76 (0.52–0.99)	0.74	N/A	N/A	N/A	0.75	N/A
Calcification	0.8 (0.63–0.93)	0.89 (0.75–1)	0.58	0.62	0.47	0.63	0.42	N/A	N/A	N/A	0.47–0.62	0.55	0.479	0.91	0.68 (0.46–0.88)
Micro-	0.49 (−0.28–1)	0.39 (−0.49–1)	0.51	0.59	N/A	N/A	N/A	0.59	N/A	0.79	N/A	0.54	N/A	N/A	N/A
Macro-	0.85 (0.59–1)	0.83 (0.6–1)	0.39	0.39	N/A	N/A	N/A	N/A	N/A	N/A	N/A	0.4	N/A	N/A	N/A
Echogenic foci	0.48 (0.3–0.64)	0.35 (0.17–0.52)	N/A	N/A	N/A	N/A	N/A	N/A	0.77 (0.56–0.99)	N/A	N/A	N/A	N/A	N/A	0.34 (0.12–0.56)
Capsule invasion	0.11 (−0.91–1)	0.4 (−1–1)	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	0.32	N/A	N/A	0.32 (–0.61–1.0)

^aMaximum k value reported in any of the two sessions; ^bAll features were grouped in two classes.

AUS/FLUS, Atypia of Undetermined Significance or Follicular Lesion of Undetermined Significance; FN, Follicular Neoplasm; N/A, not available.