Near-infrared auto-fluorescence spectroscopy combining with Fisher’s linear discriminant analysis improves intraoperative real-time identification of normal parathyroid in thyroidectomy
Abstract Background To evaluate the efficacy of a sensitive, real-time tool for identification and protection of parathyroid glands during thyroidectomy. Methods Near-infrared (NIR) auto-fluorescence was measured intraoperatively from 20 patients undergoing thyroidectomy. To determine the accuracy of NIR identification furtherly, intraoperative fast frozen pathological examination and postoperative immunohistochemical staining were performed on the suspicious parathyroid glands and other neck tissues. Data were extracted for Fisher’s linear discriminant analysis. Results The auto-fluorescence intensity of parathyroid was significantly higher than that of thyroid, fat and lymph node. The peak intensity of auto-fluorescence from parathyroid was 5.55 times as much as that from thyroid at the corresponding wave number. Of the 20 patients, the parathyroid was accurately detected and identified in 19 patients by NIR system, compared with their histopathological results. One suspicious parathyroid tissue did not exhibit characteristic spectra, and finally was proved to be fat tissue by histopathological examination. The NIR auto-fluorescence method had a 100% (19/19) sensitivity of parathyroid glands identification and a high accuracy of 95% (19/20). The positive predictive value was 95%. The parathyroid gland has specific auto-fluorescence spectrum and can be separated from the other three types of tissues through the Fisher’s linear discriminant analysis with the average accuracy rate around 90%.Conclusions NIR auto-fluorescence spectoscopy can accurately identify normal parathyroid glands during thyroidectomy. The Fisher’s linear discriminant analysis demonstrated the specificity of the NIR auto-fluorescence of parathyroid tissue and its efficacy in parathyroid discrimination.