The size of thyroid nodules contributing to the accuracy of fine-needle aspiration cytology

Abstract

Objective To evaluate the association of the size of thyroid nodules and accuracy of fineneedle aspiration cytology in diagnose of thyroid nodules.Methods 691 thyroid nodules in 630 patients pathologically confirmed were retrospectively analyzed in our hospital.All imaging data of preoperative ultrasound-guided FNAC were collected in our review.Yields of FNAC were divided into six levels according to the classification criteria of the Bethesda system(level Ⅰ,insufficient material or nondiagnosed;level Ⅱ,benign ; level Ⅲ,atypical hyperplasia; level Ⅳ,follicular neoplasm ; level Ⅴ,suspicious for malignancy; level Ⅵ,malignant),＞level Ⅳ was the malignant cytologic criteria for diagnosis of thyroid nodules.According to the maximal diameter of thyroid nodules,the nodules were divided into group A(L≤0.5 cm),group B(0.5 cm＜L＜1.0 cm) and group C(L≥1.0 cm).Postoperative pathologic results were taken as the gold standard.Results Of 691 nodules,there were 176(25.47％),298(43.13％) and 217(31.40％) in group A,group B and group C respectively.Among the three groups,accuracy of ultrasound-guided FNAC in group B (90.94 ％) was higher than in group A(80.11％) and group C(83.41 ％),with statistically significant(P ＜0.05).There was not statistically different between group A and group C(P ＞0.05).The specificity,positive predictive value and negative predictive value were not statistically different among three groups(P ＞0.05).Conclusions The size of thyroid nodules was partly associated with accuracy of ultrasound-guided FNAC. Key words: Ultrasonography ; Thyroid nodules ; Biopsy, fine-needle