Bioelectrical impedance phase angle as a diagnostic indicator in thyroid cancer

Abstract

Background: Bioelectrical impedance spectroscopy (BIS) is a non-invasive and easy-to-use technique to distinguish tissue properties. Phase angle, determined by BIS, detects changes in tissue electrical properties. We aimed to study the feasibility and validity of phase angle in diagnosis of thyroid cancer for the first time. Methods: 226 invitro thyroid specimens in 210 patients from Department of Thyroid in West China Hospital of Sichuan University from March to November 2013 were collected. According to the location from thyroid cancer, thyroid specimens were divided into four groups: A, B, C and D. All of the groups were analyzed with phase angles respectively. The results were compared with final pathologic diagnosis. Results: Results showed that the phase angle is the characteristic parameter. The rank-sum test showed, the significant difference between the four groups and between two groups (P<0.05), with statistical significance. Our study showed 86% sensitivity and 72% specificity of mean phase angle difference (MPAD). The corresponding positive and negative predictive values were 78% and 82%, overall accuracy was 80%, the area under the ROC curve is 0.838. Conclusions: The study demonstrated that phase angle can be used to diagnose thyroid cancer. With further research, the phase angle may be a potential diagnostic indicator for the thyroid cancer.