Use of Indocyanine Green and Fluorescence Angiography in Parathyroid Surgery: A Feasibility Study

Background. Indocyanine green (ICG) with near-infrared (NIR) fluorescence is an established method for assessing vascularity in various clinical settings. We hypothesized that parathyroid adenomas, with increased capillary networks, may demonstrate a fluorescence which could aid intraoperative identification and confirmation of the abnormal parathyroid tissue. Methods. This prospective case-control study compared patients with primary hyperparathyroidism undergoing parathyroidectomy (cases) to normal parathyroid in thyroidectomy patients (controls). After exposing the parathyroid gland, ICG was injected and the fluorescence of parathyroid and thyroid was recorded and graded in comparison to the surrounding tissue and vasculature (0 = nonfluorescent and 5 = vasculature). Results. The intensity of parathyroid fluorescence was more in cases (4 ± 2) than controls (2 ± 1) when graded intraoperatively (P = .001). Thyroid fluorescence did not differ (3 vs 3, P = .072); however, parathyroid fluorescence was more intense than thyroid in cases (parathyroid = 4 ± 2 and thyroid = 3 ± 1, P = .018). Conclusions. ICG fluorescence in diseased parathyroid was more intense than normal parathyroid and thyroid, suggesting the ICG/NIR technology may be a useful intraoperative tool for identification of abnormal parathyroid.