Ultrasound guided fine-needle aspiration biopsies: Comparison of sample adequacy with different needle sizes, differrent sampling technics and with/without onsite cytologic analysis

The aim of this study was to compare the adequacy of samples obtained with different sized needles, different sampling technics and with/without onsite cytologic analysis.Four hundred patients (343 women, 57 men) with solitary(n=96) or multiple (n=304) thyroid nodules underwent ultrasound (US) guided fine-needle aspiration biopsies (FNAB). Patients were randomly divided to eight groups according to needle size (NS), biopsy technic and whether onsite cytologic analysis(OCA) was performed or not. Group I: NS=22G, aspiration technic, OCA(-), Group II: NS=27G, aspiration technic, OCA(-), Group III: NS=22G, capillary technic, OCA(-), Group IV: NS=27G, capillary technic, OCA(-), Group V: NS=22G, aspiration technic, OCA(+), Group VI: NS=27G, aspiration technic, OCA(+), Group VII: NS=22G, capillary technic, OCA(+), Group VIII: NS=27G, capillary technic, OCA(+). All procedures were performed with Hitachi EUB 8500 ultrasonography system and 10 MHz linear probe. Freehand biopsy technique was used.Sample adequacy rates were calculated for each group and compared with chi-square test. The adequacy rate were 88% in group I, 88% in group II, 94% in group III , 96% in group IV, 96% in group V, 94% in group VI, 100% in group VII and 98% in group VIII. There was no significant statistical difference between groups(p=0.054). In groups I, III, V and VII hematomas were developed after the procedures in five cases. The adequacy rate was 97% with the capillary action technic versus 91,5% with the aspiration technic(p=0,032). The adequacy rate was 94.5% with 22G needle versus 94% with 27G needle size(p>0,05). There was no statistical difference adequacy rates between 22G and 27G. However statistical difference was found between groups onsite cytologic analysis(OCA) was performed or not(p=0,032).Best results were obtained with capillary technic and onsite cytologic evaluation. However, the use of 22 gauge needles carries higher risk for complications. Our experience shows that, for high adequacy rates and patient comfort at the same time, thinner needles, capillary technic and onsite cytologic analysis should be the preferred approach.