Comparison of Ultrasound-Guided Biopsy Technique for Thyroid Nodules with Respect to Adequacy of Cytological Material

Background: Ultrasound-guided fine-needle aspiration cytology (FNAC) sampling of the thyroid represents a standard diagnostic procedure in the evaluation of thyroid nodules. The specimen can be acquired using either of two different techniques. In the first, the short axis is used with observation only of the tip of the needle whilst in the nodule. In the second technique, the long axis is used with the observation of the entire length of the needle. The decision to sample utilizing either technique was done randomly. This study is a retrospective review performed to compare these two techniques with regard to specimen adequacy. Methods: Ultrasound-guided FNACs were performed in 80 thyroid nodules between May 2008 and February 2009. One physician acquired the cytology specimens using one of these two methods after localization. Data on the type of technique and its diagnostic accuracy were collected. Results: Forty-nine of 80 thyroid nodules were sampled using the long-axis technique. The overall and deep-lesion diagnostic adequacies of specimens were significantly higher using this technique (93.9 and 95.1%, respectively, p < 0.01) than the short-axis technique. When comparing the long and short axes for superficial lesions, there was no significant difference in adequacy of the samples (p = 0.92). Conclusions: This is the first study to compare long- and short-axis techniques with regard to specimen adequacy for thyroid nodules. The long-axis technique decreased the rate of inadequate material and provided more accurate cytological evaluation for deeper lesions.