Predicting tall-cell subtype of papillary thyroid carcinomas independently with preoperative multimodal ultrasound

Abstract

Objectives This study aimed to explore the differences between tall-cell subtype of papillary thyroid carcinoma (TCPTC) and classical papillary thyroid carcinoma (cPTC) using multimodal ultrasound, and identify independent risk factors for TCPTC to compensate the deficiency of preoperative cytological and molecular diagnosis on PTC subtypes. Methods 46 TCPTC patients and 92 cPTC patients were included. Each patient received grey-scale ultrasound, color Dopplor flow imaging (CDFI) and shear-wave elastography (SWE) preoperatively. Clinicopathologic information, grey-scale ultrasound features, CDFI features and SWE features of 98 lesion were compared using univariate analysis to find out predictors of TCPTC, based on which, a predictive model was built to differentiate TCPTC from cPTC and validated with 40 patients. Results Univariate and multivariate analysis identified that extrathyroidal extension (OR, 15.12; 95% CI, 2.26-115.44), aspect ratio (≥0.91) (OR, 29.34; 95% CI, 1.29-26.23), and maximum diameter ≥ 14.6 mm (OR, 20.79; 95% CI, 3.87-111.47) were the independent risk factors for TCPTC. Logistic regression equation: p = 1/1+ExpΣ[-5.099 + 3.004 × (if size ≥14.6 mm)+2.957 × (if aspect ratio≥0.91)+2.819 × (if extra-thyroidal extension)]. The prediction model had a good discrimination performance for TCPTC: the AUC, sensitivity and specificity were 0.928, 0.848 and 0.954 in cohort 1, and the corresponding values in cohort 2 were 0.943, 0.923 and 0.926. Conclusion Ultrasound has potential for differential diagnosis of TCPTC from cPTC. A prediction model based on ultrasound characteristics (extrathyroidal extension, aspect ratio ≥0.91, and maximum diameter ≥14.6 mm) was useful to predict TCPTC. Advances in knowledge Multimodal ultrasound prediction of TCPTC were supplements to preoperative cytological diagnosis and molecular diagnosis on PTC subtypes.