Table 2. Assessment of the abundance of benign nodules classified according to Kim et al.

Group	TI-RADS classification				χ2	P
	I	II	III	IV
CDFI	19	6	3	7	17.136	0.001
SMI	3	14	5	13
χ2	16.970	4.480	0.565	2.520
P	0.000	0.034	0.452	0.112

TI-RADS, Thyroid Imaging Reporting and Data System; CDFI, color Doppler imaging; SMI, superb micro-vascular imaging.