Ultrasound guided fine-needle aspiration biopsies: comparison of sample adequacy with different needle sizes and with/without onsite cytologic analysis

The aim of this study was to compare the adequacy of samples obtained with different sized needles and with/without onsite cytologic analysis.Two hundred patients(169 women, 31 men) with solitary(n=65) or multiple(n=135) thyroid nodules underwent ultrasound(US) guided fine-needle aspiration biopsies(FNAB). Patients were randomly divided to four groups according to needle size(NS) and whether onsite cytologic analysis(OCA) was performed or not. Group I: NS=21 gauge, OCA(-), Group II: NS=27 gauge, OCA(-), Group III: NS=21 gauge, OCA(+), Group IV: NS=27 gauge, OCA(+). All procedures were performed with Hitachi EUB 8500 ultrasonography system and 10 MHz linear probe. Freehand biopsy technique was used.Sample adequacy rates, number of needle passes were calculated for each group and compared with chi-square test.The number of needle passes were 1-4(mean: 2)in group I, 1-4(mean: 3)in group II, 1-4(mean 2)in group III and 1-5(mean 3)in group IV. In group III, significantly less passes were performed. Sample adequacy rates for different groups were 96%, 90%, 100% and 98% respectively. There was no significant statistical difference between groups. In groups I and III, hematomas were developed after the procedures in three cases.Best results were obtained with thicker needles and onsite cytologic evaluation. However, the use of 21 gauge needles carries higher risk for complications. Our experience shows that, for high adequacy rates and patient comfort at the same time, thinner needles and onsite cytologic analysis should be the preferred approach.KeywordsUltrasonographyThyroid GlandFine-Needle Aspiration Biopsy