Ultrasound Score to Select Subcentimeter-sized Thyroid Nodules Requiring Ultrasound-guided Fine Needle Aspiration Biopsy in Eastern China

Ultrasound-guided fine needle aspiration biopsy (FNAB) is a costly diagnostic item with a low yield in identifying the tiny proportion of nodules that actually represent malignant disease. Our aim through this study was to obtain an ultrasound (US) score for selecting subcentimeter-sized thyroid nodules requiring FNAB in eastern China. Some 248 patients for a total of 270 thyroid nodules less than 1 cm in diameter underwent FNAB and subsequent surgery from January 2006 to March 2012 at our hospital. The clinicopathological and US data from all the nodules were analyzed retrospectively. An US score was developed on the basis of independent predictive factors for malignancy. Irregular shape, hypoechogenicity, no well-defined margin, presence of calcifications and ratio between antero-posterior and transversal diameters (AP/TR) ${\geq}1$ were independent predictive factors for malignancy on logistic regression analysis. US score were statistically significant, with ${\leq}2$ favoring benignancy with an 80.3% sensitivity and a 72.7% specificity. US score is useful for differentiating between malignant and benign subcentimeter-sized thyroid nodules. We suggest FNAB for nodules when the US score is higher than 2.