Ultrasound-guided thyroid nodule fine-needle biopsies--comparison of sample adequacy with different sampling techniques, different needle sizes, and with/without onsite cytological analysis

The aim of this study was to compare the diagnostic adequacy of thyroid samples obtained by aspiration or capillary biopsy techniques, with 22 or 27 gauge needles, and with or without on-site cytological analysis (OCA). Four hundred patients with thyroid nodules underwent ultrasound (US)-guided fine-needle biopsies. Patients were divided into eight groups according to needle size (22 vs. 27 gauge), biopsy technique (aspiration vs. capillary), and whether or not OCA was performed. Sample adequacy rates were calculated for each group and subgroups and compared using chi-square tests. When all nodes were evaluated (n = 400), the adequacy rate was significantly greater with the capillary than with the aspiration technique (97% vs. 91.5%, p = 0.032) and when OCA was than was not performed (97% vs. 91.5%, p = 0.032). When only solid nodules were evaluated (n = 205) the adequacy rate was also significantly greater with the capillary than with the aspiration technique (98.9% vs. 89.7%, p = 0.008) and when OCA was than was not performed (97.9% vs. 89.6%, p = 0.014). In contrast, the adequacy rate was similar for 22 and 27 gauge needles (94.2% vs. 93.1%, p = 0.733). Optimal results were obtained with the capillary technique and OCA. The capillary technique and OCA should be the preferred approach in thyroid nodule biopsy, optimising adequacy rates and patient comfort.