Factors Influencing the Reliability of Thyroid Fine-Needle Aspiration: Analysis of Thyroid Nodule Size, Guidance Mode for Aspiration and Preparation Method

Objective: We aimed to clarify the influence of ThinPrep preparation, nodule size and guidance mode on the accuracy of thyroid fine-needle aspiration (FNA). Methods: A total of 1,240 thyroid FNAs were reviewed and 489 cases with histological correlations were enrolled in this study. Results: Of the 489 total cases examined, 101 were processed with both ThinPrep and conventional preparation and 388 entirely with ThinPrep. The overall nondiagnostic rate, sensitivity and accuracy of FNA were 2.0, 91.0 and 89.4%, respectively. The cases with a preoperative ultrasound (n = 469) were grouped according to nodule size. The nondiagnostic rate, sensitivity and accuracy of FNA did not differ significantly with nodule size (p1 = 0.339, p2 = 0.179, p3 = 0.119). A total of 101 resections were performed with palpation-guided FNA and 388 were performed with ultrasound-guided FNA. The nondiagnostic rates, sensitivity and accuracy of FNA were similar in these two groups. Conclusions: The ThinPrep technique is a valid method for thyroid FNA and is effective for thyroid nodules ≥0.5 cm. The reliability of FNA results is not reduced with larger nodules. The use of palpation-guided FNA for palpable solid nodules is also effective.

Comparison of Thinprep versus Conventional Smear Cytopreparatory Techniques for Fine-Needle Aspiration Specimens of Head and Neck Masses

OBJECTIVES: Diagnostic accuracy of the ThinPrep process (Cytyc, Boxborough, MA) was compared with that of conventional (smear) cytopreparation for fine-needle aspiration (FNA) of head and neck masses. METHODS: In a prospective, randomized, single-blinded study, 209 patients served as their own controls and underwent 236 FNAs using ThinPrep and conventional (smear) cytopreparatory techniques. RESULTS: ThinPrep produced less air-drying artifact and less mechanical distortion than the conventional method. The conventional technique was diagnostic in 63% of samples; the ThinPrep technique was diagnostic in 55% of samples. When all results were combined, pathologists subjectively preferred the conventional technique but accepted use of ThinPrep as the only cytopreparatory technique for most head and neck masses. CONCLUSIONS: For adequately experienced cytopathologists, ThinPrep is acceptable for FNA of salivary masses, neck cysts, metastatic lymph nodes, and thyroid lesions. Conventional smear technique should be used for FNA of nonmetastatic lymphoid lesions. Use of ThinPrep can complement use of the conventional (smear) cytopreparatory technique when aspirate is nondiagnostic or bloody, when the patient has a blood-borne infectious disease, when the clinician is inexperienced, or when aspirate has entered the syringe.