Differential Diagnosis of Thyroid Follicular Neoplasm from Nodular Hyperplasia by Shear Wave Elastography

ABSTRACT

OBJECTIVE: More than 50% of diagnostic surgery in cytologically indeterminate thyroid nodules revealed benign nodules of which nodular hyperplasia (NH) accounted for about half. Preoperative exclusion of NH may decrease diagnostic surgery. We aimed to study the diagnostic performance of shear wave elastography (SWE) to differentiate follicular neoplasm (FN) from NH in follicular lesions of thyroid nodules. METHODS: We analyzed the data from 61 patients who underwent SWE before ultrasound-guided core-needle biopsy (CNB) from August 2016 to May 2018 and CNB results were FN (n=19) and NH (n=42). We analyzed the magnitude of elasticity index (EI) and patterns of high EI area (EI >36 kPa). The patterns of high EI area was classified as marginal pattern (high EI areas are restricted in the outer 1/3 of the nodule) and traversing pattern (high EI areas approaching further to the center of the nodule within inner 2/3 of the nodule). RESULTS: The E(Max), E(Mean), E(SD), and percent of high EI area were significantly lower in FN than NH (P<0.001). The diagnostic performance to predict FN showed sensitivity, specificity, and accuracy of 95%, 90%, and 92% by E(Max) <42.1 kPa, and of 95%, 79%, and 84% by E(Mean) <23.5 kPa, and of 89%, 93%, and 92% by marginal pattern of high EI area, respectively. CONCLUSION: Novel diagnostic criteria of E(Max) less than 42.1 kPa and marginal pattern of high EI area on SWE can predict FN with high diagnostic accuracy, waiving diagnostic surgery of NH in indeterminate cytology.