title: Ultrasound-guided fine needle aspiration of thyroid nodules: factors affecting diagnostic outcomes and confounding variables.
abstract: Background The incidence of thyroid cancer is increasing in men and women. Fine needle aspiration (FNA) is an accepted technique to assess thyroid nodules but is associated with a high rate of non-diagnostic sampling. Purpose To assess the diagnostic performance of ultrasound-guided FNA of thyroid nodules and identify factors associated with non-diagnostic sampling. Material and Methods A retrospective review of thyroid FNAs was performed between 2006 and 2013. Patient demographics, nodule characteristics, procedural technique, cytology, and complications were recorded. Cytology was categorized THY1-5 based on the British Thyroid Association guidelines. Descriptive and multivariable analysis were conducted to identify factors associated with non-diagnostic sampling. Results A total of 724 procedures were identified with 597 (82.5%) in women, and an overall mean age of 40 years (age range, 17-87 years). Factors associated with a non-diagnostic outcome in the multivariable regression analysis included increasing lesion depth (OR, 1.05 per mm; 95% confidence interval [CI], 1.007-1.10), age (OR, 1.012 per year; 95% CI, 1.0-1.025) and number of FNA passes (1 vs. 4+; OR, 6.07; 95% CI, 2.27-16.21). The complication rate was 1.1% related to perilesional hematomas and vaso-vagal episodes. Conclusion Thyroid FNA is a safe and reliable procedure for cytological assessment of thyroid nodules. Deeper nodules and older patients are more likely to have non-diagnostic samples.
authors.affiliation: 1 Department of Radiology, St. James's Hospital, Dublin, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Kavanagh
authors.affiliation: 1 Department of Radiology, St. James's Hospital, Dublin, Ireland.
authors.forename: Niall
authors.initials: N
authors.lastname: McVeigh
authors.affiliation: 1 Department of Radiology, St. James's Hospital, Dublin, Ireland.
authors.forename: Eoghan
authors.initials: E
authors.lastname: McCarthy
authors.affiliation: 2 Department of Pharmacology & Therapeutics, Trinity Centre for Health Sciences, St James's Hospital, Dublin, Ireland.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Bennett
authors.affiliation: 1 Department of Radiology, St. James's Hospital, Dublin, Ireland.
authors.forename: Peter
authors.initials: P
authors.lastname: Beddy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D061705:Image-Guided Biopsy; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology*; D018084:Ultrasonography, Interventional / Q000379:methods*; D055815:Young Adult
keywords: Thyroid nodules; cytology; fine needle aspiration; non-diagnostic