Ultrasound-guided fine-needle aspiration biopsy of thyroid nodules: comparison in efficacy according to nodule size.
BACKGROUND
The objective of this study was to compare the efficacy and procedure time of ultrasound-guided fine-needle aspiration biopsy (US-FNAB) of thyroid nodules, according to the nodule size.


METHODS
US-FNABs of thyroid nodules performed between June 2007 and December 2007 were studied. We divided these patients into three groups according to the largest diameter of their nodules. Group A consisted of patients with thyroid nodules less than or equal to 5 mm, group B of patients with thyroid nodules greater than 5 mm and less than or equal to 10 mm, and group C of patients with thyroid nodules greater than 10 mm. We retrospectively reviewed the cytopathology results and complications in all three patient groups and measured the separate, total US-FNAB procedure time for each of 20 randomly selected thyroid nodules.


RESULTS
US-FNAB was performed on 438 thyroid nodules in 253 patients. In groups A, B, and C, the adequacy rates from the first US-FNAB were 79.6% (90/113), 90.6% (125/138), and 95.2% (178/187), respectively. In groups A, B, and C, 113, 138, and 187 thyroid nodules in 100, 120, and 169 patients, respectively, revealed 59, 75, and 126 benign; 12, 11, and 9 suspicious for malignancy; 9, 32, and 29 malignant; 10, 7, and 14 inderminate for malignancy; and 23, 13, and 9 inadequate on the first US-FNAB. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were determined to be 85.7%, 100%, 100%, 94.9%, and 96.1% in group A; 97.7%, 100%, 100%, 98.7%, and 99.1% in group B; and 100%, 99.2%, 97.1%, 100%, and 99.4% in group C. The mean procedure times in groups A, B, and C were 2 minutes 33 seconds, 1 minute 50 seconds, and 1 minute 32 seconds, respectively. There were no significant patient complications in any of the three patient groups.


CONCLUSIONS
US-FNAB of thyroid nodules smaller than 5 mm in maximum diameter was less successful, and the sensitivity was lower than those of nodules larger than 5 mm. We considered, however, that the sampling adequacy and efficacy of US-FNAB of thyroid nodules less than 5 mm in maximum diameter was satisfactory in our series and should be similar in other centers with similar characteristics to ours.
Kim
Dong Wook
DW
Department of Radiology, Busan Paik Hospital, Inje University College of Medicine , Busan, South Korea. dwultra@lycos.co.kr
Lee
Eun Joo
EJ
Kim
Sang Hyo
SH
Kim
Tae Hyun
TH
Lee
Sang Hyub
SH
Kim
Dae Hwan
DH
Rho
Myung Ho
MH
D000293:Adolescent; D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology*; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult