Fractal Dimension Differentiation between Benign and Malignant Thyroid Nodules from Ultrasonography

Abstract

Recently, there is increasing interest in identifying benign and malignant nodules by using ultrasound diagnostic technology, which should be helpful to release patients with benign thyroid nodules from suffering unnecessary needle biopsy. In this work, fractal analysis was investigated for the capability of differentiating benign from malignant thyroid nodules during ultrasonography. The B-mode images for 57 patients with suspicious thyroid nodules were captured, followed by ultrasound-guided needle aspiration. The region of interests (ROIs) were subsequently selected from ultrasound images. Then, fractal analysis was performed to extract fractal texture features, and derive the fractal dimension of ROI. The results showed that a significant difference was observed between benign and malignant thyroid nodules (p < 0.05), by comparing this parameter based on independent nonparametric Mann‒Whitney U test. It suggested that fractal dimension is a helpful feature for distinguishing thyroid nodules. In addition, fractal analysis of the B-mode image can provide a reliable reference for tissue typing in ultrasound diagnosis.