Comparison of the Diagnostic Efficacy of Ultrasound-Guided Core Needle Biopsy With 18- Versus 20-Gauge Needles for Thyroid Nodules

OBJECTIVES To compare the diagnostic efficacy, complication rate, and core needle biopsy (CNB) specimen yield in 18- versus 20-gauge ultrasound (US)-guided CNB for diagnosis of thyroid nodules. METHODS We included 81 consecutive thyroid nodules with US-guided biopsy by a 20-gauge core needle and 86 consecutive thyroid nodules with US-guided biopsy by an 18-gauge core needle during 2 years. The rate of inconclusive results, including nondiagnostic or atypia/follicular lesion of undetermined significance, was compared. The diagnostic performance for malignancy was assessed in nodules with a final diagnosis. The complication rate and CNB specimen yield were also compared. RESULTS Eighteen-gauge CNB showed a lower rate of nondiagnostic results (1.2% versus 8.6%; P = .024) than 20-gauge CNB; however, the rates of atypia/follicular lesion of undetermined significance and inconclusive results were not significantly different between the groups (P > .05). In addition, 18-gauge CNB showed higher sensitivity (75.0% versus 66.7%), a higher negative predictive value (83.9% versus 75.9%), and higher accuracy (78.3% versus 74.4%) for detecting malignancy than 20-gauge CNB, although the results did not achieve statistical significance. No major complications occurred in either of the CNB groups. The 18-gauge needle group had significantly fewer CNBs and larger specimen diameters (P