Potential causes for obtaining non-diagnostic results from fine needle aspiration biopsy of thyroid nodules

The aim of this prospective study was to evaluate factors that could affect the diagnostic result success ratio of fine needle aspiration biopsy of thyroid nodules. 664 patients and 696 nodules were included in this study. Demographic features of age and gender and nodule features of macrocalcification (MC) and internal content (cystic or solid predominance) were evaluated. All biopsies were performed from 1 cm or larger nodules. Three different size needles were used for comparison (22, 23 and 25 G). The patients in each group had a similar number of nodules with MC, and cystic predominance to obtain comparable results. All procedures were performed by the same radiologist, who had 4 years of experience. Histologically adequate material criteria were identified. All pathological specimens were evaluated as diagnostic or non-diagnostic by the same pathology technician. Chi-square, student's t test and univariate analysis were used for statistical analysis. There were no statistically significant differences in demographic features and nodule properties from diagnostic results of fine needle aspiration biopsy of thyroid nodules. On the other hand, 23 G needles offered a better potential for obtaining adequate samples with a statistically significant difference. Obtaining adequate material in fine needle aspiration biopsy from thyroid nodules is a challenging issue and the results are controversial. Since we obtained the best ratio with 23 G needles, we recommend interventional radiologists to use 23 G needles as far as possible and not to consider needles thicker needles than 22 G or thinner than 25 G. Nodule features and demographic features did not have an effect on obtaining adequate cytological material.