Abstract
1124
Introduction: Hyperparathyroidism is a disease caused by enhanced levels of parathyroid hormone (PTH) in blood. This can be due to parathyroid disease (primary hiperthyroidism, PHP) or chronic kidney disease (secondary hiperparthyroidsm, SHP). Some of these patients will have indication of parathyroid removal through surgery. Radioguided parathyroid surgery using 99mTc sestamibi has been used to aid in the localization and removal of parathyroid adenomas. More recently intraoperative fluorescence imaging has been used to detect parathyroid glands. Intraoperative intravenous indocyanine green (ICG) injection accumulates in normal and pathologic parathyroid tissue allowing parathyroid visualization. Also near infrared parathyroid fluorescence imaging can be used to localize parathyroid tissue. The aim of this work was to provide examples of intraoperative parathyroid detection through radionuclide and fluorescence imaging and highlight their strenghts and limitations and complementary role. MATERIALS We describe 3 patients with PHP (n=1) and SPH (n=2) in whom parathyroid surgery was performed. In the first patient with PHP, radioguided surgery with 99mTc sestamibi was performed using a gamma probe to detect the parathyroid adenoma following the acustic cues. In one SPH patient ICG was intravenously injected once the thyroid was dissected and a portable near infrared fluoresence (NIRF) was used to detect ICG fluorescence. While searching for parathyroid block surgery lights had to be turn off. In the last SPH patient, we looked at ex vivo autofluorescence of parathyroid gland after removal and prior pathologic confirmation, using a modification of NIRF system setup in a room were lights were turn off.
Results: Intraoperative radioguided parathyroid identification with 99mTc sestamibi was succesfully performed and the acoustic cue was used to find and remove parathyroid adenoma. When using ICG intraoperatively we found that it was accumulated by parathyroid tissue being able to detect and visualize their fluorescence and differentiate it from non fluorescence tissue such as fat or nodes. Also we saw thyroid fluorescence. ICG near infrared imaging aided surgeons in parathyroid identification and removal. Best fluorescence signal is obtained when there is no tissue over the parathyroid blocking their fluorescence. When looking at parathyroid autofluorescence we found that our NIRF system setup allowed us to visualize parathyroid tissue. Later pathology confirmed the removed tissue was parathyroid tissue.
Conclusions: Parathyroid surgery has indications for hiperparathyroidism bearing patients. The best outcome of this procedure is to find an experienced surgeon. Radioguided surgery and fluorescence molecular imaging can aid surgeons in their search for parathyroids and would provide them with new tools towards a successful surgery.
