title: The diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy and the sonographic differences between benign and malignant thyroid nodules 3 cm or larger.
abstract: BACKGROUND
  Although fine-needle aspiration biopsy (FNAB) is considered the standard for preoperative evaluation of thyroid nodules, the value of this has been questioned for large thyroid nodules. Here, we evaluated the diagnostic accuracy of ultrasound-guided FNAB (US-FNAB) for thyroid nodules that were 3 cm or larger as well as the sonographic differences between benign and malignant nodules in this size group.
  
  
  METHODS
  There were 661 thyroid masses equal to or larger than 3 cm who underwent US-FNAB from February 2002 to December 2006 and were included in this study. The cytology and surgical pathology readings in these patients were reviewed along with the ultrasonography features, the last from the retrospective review by one radiologist. Histopathology was used to calculate accuracy parameters for the US-FNAB cytology readings. In addition, the likely diagnoses for patients with a benign cytology reading were ascertained.
  
  
  RESULTS
  Thyroid surgery was performed for 206 of the 661 nodules in the same number of patients (31.2%). All subjects who had inadequate, indeterminate, or suspicious for malignancy cytology readings had thyroid surgery. All of the patients who did not have thyroid surgery were considered likely to have benign disease because of their initial cytology reading and follow-up, and finally, 587 (88.8%) were benign and 74 (11.2%) were malignant. When considering malignant, suspicious for malignancy, and indeterminate cytology readings as positive and benign cytology as negative, the sensitivity was 96.7%, specificity 85.9%, positive predictive value 76.6%, negative predictive value 98.2%, and accuracy 89.4%. Ultrasonography features of malignancy were more prevalent in thyroid nodules that were malignant compared with those that were benign or considered likely to be benign (70.3% vs. 1.2%, p < 0.001), and ultrasonography features of a benign nodule were more prevalent in thyroid nodules that were benign or considered likely to be benign than those that were malignant (94.9% vs. 29.7%, p < 0.001).
  
  
  CONCLUSIONS
  In this study, US-FNAB appeared to be a relatively accurate method to evaluate thyroid nodules larger than 3 cm, with false-negative rates of about 2%. Much larger series would be required to determine its utility in this setting.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Kim
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D016009:Chi-Square Distribution; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D056910:Republic of Korea; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D016606:Thyroid Nodule / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy; D047368:Tumor Burden; D018084:Ultrasonography, Interventional; D055815:Young Adult