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Univariate and multivariate analysis of 710 PTMC primary sites with US features for predicting ipsilateral lymph node metastasis

Features	Cases	Patients [n (%)]		χ2	P	Multivariate model
		LNs (–)	LNs (+)			Odds ratio	95% CI	P
Size (cm)				21.611	0.000	2.430	1.479–3.994	0.000
≤ 0.5	159	134 (84.3)	25 (15.7)
> 0.5, ≤ 1	551	358 (65.0)	193 (35.0)
Taller-than-wide				2.764	0.099	1.375	0.915–2.066	0.125
< 1	189	140 (74.1)	49 (25.9)
≥ 1	521	352 (67.6)	169 (32.4)
Peripheral vascularity				2.680	0.117	1.771	0.810–3.876	0.152
Yes	678	474 (70.0)	204 (30.0)
No	32	18 (56.3)	14 (43.7)
Location				38.882	0.000	0.645	0.535–0.778	0.000
Isthmus	17	17 (100.0)	0 (0.0)
Upper	249	140 (56.2)	109 (43.8)
Middle	168	118 (70.2)	50 (29.8)
Lower	276	217 (78.6)	59 (21.4)
Echogenicity				0.982	0.354	0.939	0.506–1.742	0.842
Hyper or iso-echoic	74	55 (74.3)	19 (25.7)
Hypo-echoic	636	437 (68.7)	199 (31.3)
Calcification				27.123	0.000	2.649	1.672–4.197	0.000
No	190	160 (84.2)	30 (15.8)
Yes	520	332 (63.8)	188 (36.2)
Margin				7.840	0.005	2.397	0.995–5.775	0.051
Clear	52	45 (86.5)	7 (13.5)
Unclear	658	447 (67.9)	211 (32.1)
Abutment/perimeter				8.691	0.004	1.712	1.180–2.483	0.005
≤ 0.25	245	187 (76.3)	58 (23.7)
> 0.25	465	305 (65.6)	160 (34.4)