title: Ultrasound-guided fine needle aspiration cytology in the diagnosis and management of thyroid nodules.
abstract: OBJECTIVE
  To examine the accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of thyroid nodules and compare the inadequacy rates for ultrasound-guided and freehand FNAC.
  
  
  METHODS
  A retrospective study of 434 patients with thyroid nodules who underwent diagnostic FNAC over a 2-year period. Cytological diagnoses have been compared with the histological assessment of resection specimens in 69 cases.
  
  
  RESULTS
  The inadequacy rate was significantly lower from ultrasound guided FNAC (24/373 cases, 6.4%) than from freehand FNAC (8/61 cases, 13.1%) (P = 0.043). Seventy-six percentage of patients had a non-neoplastic cytological diagnosis and, after multidisciplinary review, the patients were reassured and assigned to clinical follow-up. Sixty-seven patients had a resection for cytological appearances consistent with non-neoplastic disease (n = 34), suspicious of follicular neoplasia (n = 23), or suspicious of malignancy (n = 10), and two patients had resections following inadequate cytology with ultrasound appearances suspicious of a neoplasm. The overall accuracy of FNAC analysis for malignancy was 97.0%, with sensitivity 83.3%, specificity 98.0%, positive predictive value 71.4% and negative predictive value 98.4%. The overall accuracy of FNAC analysis for the prediction of neoplasia was 97.5%, with sensitivity 80.5%, specificity 97.8%, positive predictive value 89.2% and negative predictive value 95.9%. Difficulties in cytological diagnosis were associated with lymphoid infiltrates and with degenerative changes in follicular adenomas.
  
  
  CONCLUSIONS
  Ultrasound-guided FNAC has a significantly lower yield of inadequate aspirates than palpable FNAC. The ability of FNAC to predict neoplasia in 89% patients and to exclude neoplasia in 95.9% patients makes an important contribution to the multidisciplinary assessment of patients.
authors.affiliation: Department of Pathology, Radiology and Surgery, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: X J
authors.initials: XJ
authors.lastname: Cai
authors.forename: N
authors.initials: N
authors.lastname: Valiyaparambath
authors.forename: P
authors.initials: P
authors.lastname: Nixon
authors.forename: A
authors.initials: A
authors.lastname: Waghorn
authors.forename: T
authors.initials: T
authors.lastname: Giles
authors.forename: T
authors.initials: T
authors.lastname: Helliwell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000601:surgery*; D016606:Thyroid Nodule / Q000175:diagnosis*; D014463:Ultrasonography