Near-Infrared Autofluorescence Image-Guided Parathyroid Gland Mapping in Thyroidectomy

Studies to date have shown that near-infrared autofluorescence imaging (NIR) can detect the parathyroid gland during thyroidectomy. However, there are no reports that NIR imaging can identify the parathyroid gland when it's covered with fibrofatty tissue before identification by a surgeon's naked eye. In this study, we investigated the feasibility of parathyroid gland mapping to facilitate early identification of the parathyroid gland during thyroidectomy.

Seventy parathyroid glands from 38 patients who underwent thyroidectomy for papillary thyroid cancer were included in this prospective study. Near-infrared with infrared illumination (NIR-IR) imaging using a 780-nm light-emitting diode was conducted at the predicted locations of the superior or inferior parathyroid glands. Parathyroid mapping was conducted in 3 stages. Stages P1, P2, and P3 were defined as imaging before identification of the gland by direct visualization, imaging after identification, and imaging in the removed specimen, respectively.

Sixty-four parathyroid glands (92.8%) could be localized in stage P1 before surgical dissection and exposure of the gland. Five parathyroid glands that were not detected at stage P1 were identified in stages P2 (4 cases, 5.8%) and P3 (1 case, 1.4%). One parathyroid gland was not identified in either the NIR imaging or the pathologic examination. The sensitivity, specificity, and accuracy of parathyroid gland mapping in stages P1, P2, and P3 were all 100%.

Parathyroid gland mapping using our NIR-IR imaging technique was feasible, with an excellent accuracy rate. This technique may be helpful for early identification of parathyroid glands during thyroidectomy.