EFFICIENT PARATHYROIDECTOMY GUIDED BY SPECT-MIBI AND HORMONAL MEASUREMENTS

Parathyroidectomy is a difficult and lengthy operation which is noncur ative in 6% to 10% of cases. To improve the efficiency of this operati on, a new dual diagnostic approach was prospectively applied. Methods: Preoperative tomographic Tc-99m-sestamibi (MIBI) scintigraphy and int raoperative measurements of circulating parathyroid hormone (PTH) leve ls by a quick assay (QPTH) were used. Scintigraphy comprised immediate and delayed planar and SPECT of the neck and chest, following 20 mCi MIBI, The presence and location of persistent foci of abnormal activit y found within the neck and mediastinum on volume-rendered reprojectio n (RPJ) of the SPECT data were reported. The surgeon, guided by the th ree-dimensional MIBI-SPECT/RPJ images, identified and excised the sing le or most prominent scintigraphic focus and applied the QPTH. If PTH levels fell from baseline by at least 50%, the operation was concluded . Results: The operative time of primary parathyroidectomy was reduced from an average of 90 min (before the introduction of scintigraphy an d intraoperative PTH measurements) to 57 min. All but two patients bec ame normocalcemic. In 58 consecutive patients with hyperparathyroidism , MIBI-SPECT/RPJ correctly and precisely identified 51 of 53 (96%) pri mary parathyroid adenomas, 14 of 15 secondary hyperplasias and 2 of 3 hyperplastic glands in MEN (sensitivity 94%, specificity 92%). QPTH ve rified the excision of the primary parathyroid adenomas and predicted normocalcemia in 50 of 52 patients. In 6 patients with misleading scin tigraphy, QPTH was especially useful and guided the surgeon to continu e the operation until the abnormal parathyroid tissue was found and ex cised. Conclusion: MIBI-SPECT/RPJ and QPTH sequentially applied improv ed the efficiency of parathyroidectomy.