Real-time ultrasound-guided fine needle cytology of the thyroid gland by capillary action. A modified technique without aspiration.

Purpose: To present a modified technique of real-time (Rt) ultrasound-guided (Ug) fine-needle (FN) cytology of thyroid nodules without aspiration (RtUg-FNNAC).

Methods: We retrospectively studied 958 patients with 1202 thyroid nodules referred to our institution between January 2009-January 2010. The efficacy of RtUg-FNNAC was determined by the number of satisfactory specimens that were obtained. Furthermore, we compared the RtUg-FNNAC results with the surgical histological results.

Results: All specimens were adequate for diagnosis. Two hundred and twelve (22.1% patients with malignant cytological findings and 20 (2.1%) with indeterminate cytological findings were referred for surgery. All nodules with malignant and indeterminate cytological findings were confirmed histologically. From 20 indeterminate cytological findings 17 (85%) were malignant. From 66 patients with initial benign RtUg-FNNAC who were subjected to surgery the results were true negative in 65 and false negative in 1. Finally, RtUg-FNNAC was true positive in 229 cases and false positive in 3. The overall sensitivity, specificity, positive predictive value and negative predictive value of RtUg-FNNAC were 99.6, 95.6, 98.7 and 98.7%, respectively. Accuracy for the detection of malignancy was 98.7%.

Conclusion: RtUg-FNNAC is a technique that combines the benefits of real time US-guidance with those of capillary action sampling, maximizing cellular yield and minimizing bloody artefacts in cytologic examination.