3.

Univariate and multivariate logistic regression analysis of 486 PTMC primary sites with US features for predicting level VI lymph node metastases

Features	Cases	Patients [n (%)]		χ2	P	Multivariate model
		LNs (–)	LNs (+)			Odds ratio	95% CI	P
Size (cm)				19.495	0.000	1.250	0.922–1.696	0.151
≤ 0.5	131	72 (54.96)	59 (45.04)
> 0.5, ≤ 1	355	117 (32.96)	238 (67.04)
Taller-than-wide				3.602	0.063	1.128	0.593–2.095	0.623
< 1	46	25 (54.35)	21 (45.65)
≥ 1	440	164 (37.27)	276 (62.73)
Peripheral vascularity				3.631	0.086	1.297	0.721–2.332	0.385
Yes	471	186 (39.49)	285 (60.51)
No	15	3 (20.00)	12 (80.00)
Location				9.886	0.020	1.105	0.975–1.254	0.119
Isthmus	22	10 (45.45)	12 (54.55)
Upper	138	69 (50.00)	69 (50.00)
Top	118	43 (36.44)	75 (64.56)
Lower	207	67 (32.37)	140 (67.63)
Echogenicity				4.234	0.046	1.216	0.772–1.916	0.399
Hyper or iso-echoic	47	25 (53.19)	22 (46.81)
Hypo-echoic	439	164 (37.35)	275 (62.65)
Calcification				25.094	0.000	1.461	1.093–1.955	0.011
No	157	91 (57.96)	66 (42.04)
Yes	329	98 (29.79)	231 (70.21)
Margin				5.858	0.018	1.111	0.665–1.857	0.688
clear	43	23 (53.49)	20 (46.51)
unclear	443	166 (37.47)	277 (62.53)
Abutment/perimeter				23.504	0.000	1.446	1.134–1.844	0.003
≤ 0.25	221	115 (52.04)	106 (47.96)
> 0.25	265	74 (27.92)	191 (72.08)