ABSTRACT
Objective To investigate diagnostic value of CT signs in papillary thyroid carcinoma (PTC) by comparing CT signs of PTC with different sizes.Methods CT signs of 406 PTC from 396 patients confirmed by histology were analyzed retrospectively.Based on the largest tumor diameter,PTC were divided into 1.1-2.0 cm group,2.1-3.0 cm group and＞3.0 cm group.Distribution of irregular shape,cookie bite sign,enhanced narrow/ fuzzy and microcalcification in each group was analyzed.Results There were 318 pieces in 1.1-2.0 cm group,60 pieces in 2.1-3.0 cm group and 28 pieces in ＞3.0 cm group,respectively.The rate of irregular shape was 89.6％(285/318),75.0％(45/60) and 64.3％(18/28) in each group,the rate of cookie bite sign was 83.6％(266/318),71.7％(43/60) and 64.3％ (18/28),and enhanced narrow/fuzzy was 84％(267/318),78.3％ (47/60) and 67.9％ (19/28) in each group,and microcalcification was 35.5％ (113/318),40.0％ (24/60) and 59.3％ (16/27) in each group.The rate of irregular shape (x2=20.092,P=0.000)and cookie bite sign (x2=9.695,P=0.008)had statistical difference among the three groups,while the rate of enhanced narrow/fuzzy(x2=5.175,P=0.075)and microcalcification (x2=5.277,P=0.071) had no statistical difference among each group.Furthermore,irregular shape and cookie bite sign were compared between groups.Rate of irregular shape in 1.1-2.0 cm group and 2.1-3.0 cm (x2=9.746,P=0.002)group,1.1-2.0 cm group and ＞ 3.0 cm group (x2=15.180,P=0.000) was statistically different.Rate of cookie bite sign in 1.1-2.0 cm group and ＞3.0 cm(x2=6.560,P=-0.010)was statistically different.There was no statistical difference between other groups.Conclusions Although irregular shape,cookie bite sign,enhanced narrow/fuzzy and microcalcification are important CT signs in diagnosing PTC,distribution of different signs varies with tumor sizes.Correct identification of these differences will help to improve the accuracy of preoperative diagnosis,and reduce occurrence of misdiagnosis.