Intraoperative Real-Time Localization of Normal Parathyroid Glands With Autofluorescence Imaging

Context: This biomedical investigation is valuable for identification and localization of parathyroid glands during thyroidectomy, which can provide an intraoperative real-time visual guidance. Objective: The objective of the study was to investigate the feasibility of real-time autofluorescence imaging of the parathyroid glands without exogenous contrast dye for their localization and demonstration of relation to the background tissues. Setting: This research was undertaken at Kosin University Gospel Hospital. Methods: Sixteen normal parathyroid glands from eight patients with papillary thyroid carcinoma were enrolled. Photo images of the surgical field including the parathyroid and background tissues were taken with a digital camera, 780 nm light-emitting diode to excite the parathyroid, and infrared illuminator to visualize the entire neck. The area-averaged autofluorescence intensity of parathyroid over the area-averaged fluorescence intensity of background tissues was measured. Main Outcome Measure: The location of the parathyroid gland was verified with a single image. Results: The area-averaged autofluorescence intensity of parathyroid over the area-averaged fluorescence intensity of background tissues for all parathyroid glands was higher than 1, with a minimum of 1.95 and a maximum of 5.20 (average 2.76, SD 0.79). By our technique, all 16 parathyroid glands were detected (positive predictive value of 100%), and the entire surgical field including the parathyroid and background tissues was visualized as well. The parathyroid glands that were exposed or even covered by connective tissues or blood vessels could be detected with strong emission. Conclusions: This method showed the precise localization of the parathyroid glands and demonstrated their relation to background tissue. We believe that this simple, nonexogenous dye technique of anatomical guidance can aid surgeons to preserve parathyroid glands during thyroidectomy.