Prediction of Extrathyroidal Extension Using Ultrasonography and Computed Tomography

Table 4

Positive predictive value of combining of US and CT according to tumor size.

(a) Tumor less than 1 cm

Percentage of ETE+ (%)	CT features
	Group A	Group B	Group C	Group D
US features
Group 1	10.0	17.1	35.8	NA^*
Group 2	22.5	45.2	42.1	78.6
Group 3	25.4	62.9	87.0	92.7

NA: not applicable.

(b) Tumor larger than 1 cm

Percentage of ETE+ (%)	CT features
	Group A	Group B	Group C	Group D
US features
Group 1	6.2	22.6	37.7	NA^*
Group 2	13.6	52.7	70.5	83.2
Group 3	18.5	75.4	89.1	94.5

NA: not applicable.