Logistic regression analysis of conventional ultrasonography, strain elastosonography, and contrast-enhanced ultrasound characteristics for the differentiation of benign and malignant thyroid nodules

Abstract

The aim of the study is to screen the significant sonographic features by logistic regression analysis and fit a model to diagnose thyroid nodules. A total of 525 pathological thyroid nodules were retrospectively analyzed. All the nodules underwent conventional ultrasonography (US), strain elastosonography (SE), and contrast -enhanced ultrasound (CEUS). Those nodules' 12 suspicious sonographic features were used to assess thyroid nodules. The significant features of diagnosing thyroid nodules were picked out by logistic regression analysis. All variables that were statistically related to diagnosis of thyroid nodules, at a level of p < 0.05 were embodied in a logistic regression analysis model. The significant features in the logistic regression model of diagnosing thyroid nodules were calcification, suspected cervical lymph node metastasis, hypoenhancement pattern, margin, shape, vascularity, posterior acoustic, echogenicity, and elastography score. According to the results of logistic regression analysis, the formula that could predict whether or not thyroid nodules are malignant was established. The area under the receiver operating curve (ROC) was 0.930 and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 83.77%, 89.56%, 87.05%, 86.04%, and 87.79% respectively.

Fig 1. The ROC curve of logistic regression.

Fig 2. Ultrasonography images of a malignant thyroid nodule in the right lobe of a 44-year-old woman.

The calculated predictive value with the logistic regression formula was 0.980. Surgical pathology proved a papillary thyroid carcinoma. (a) Conventional US image showing a thyroid nodule with irregular margin, ill-defined border, taller-than-wide shape, hypoechogenicity in the longitudinal section. (b) Color Doppler US image showing central vascularity in the transversal section. (c) SE image showing elastography score of 4 in the longitudinal section. (d) CEUS image showing a heterogeneous mass with hypo-enhancement pattern in the longitudinal section.

Fig 3. Ultrasonography images of a benign thyroid nodule in the right lobe of a 50-year-old woman.

The calculated predictive value with the logistic regression formula was 0.412. Surgical pathology proved a nodular goiter. (a) Conventional US image showing a thyroid nodule with microcalcification, and peripheral acoustic halo in the longitudinal section. (b) Color Doppler US image showing presence of central vascularity in the longitudinal section. (c) SE image showing elastography score of 3 in the longitudinal section. (d) CEUS image showing a heterogeneous mass with hypo-enhancement pattern in the longitudinal section.