Ultrasound-Guided Fine Needle Aspiration (USFNA) of Thyroid Nodules; Does Aspiration Site Matter?

The goal of ultrasound guided fine-needle aspiration (USFNA) is to obtain most cellular specimen that represents the nodule. However, there is substantial variability in specimen cellularity depending on the obtaining techniques. While performing USFNA, it is not clear whether the needle tip should be placed at hypovascular or hypervascular site of the nodule to obtain more cells for cytological analysis.

The aim of the study was to assess whether USFNA of the hypovascular or hypervascular site of a thyroid nodule would reveal more cells for cytological analysis.

Twenty-three consecutive patients with solid thyroid nodules larger than 2 cm were aspirated under color Doppler sonography guidance. First pass was from the hypovascular site and the second pass from the hypervascular site. The aspirates were scored from 1-3 by cytologist according to number of cell groups.

When only hypervascular site was used, adequate sampling was limited to 65% of the cases. When both sites were evaluated together, overall adequate sampling was 91%. Adding a sample from the hypervascular site to hypovascular aspirate increased the adequate sampling by 8%. The highest pathological score was achieved when both hypo- and hypervascular site aspirates were evaluated together.

The aspirates from the hypovascular and hypervascular sites of solid nodules are complementary and should be performed consecutively.