Tc-99m-MIBI-scintigraphy before parathyroid surgery?

Aim: In a non prospective study the value of preoperative parathyroid imagi ng with Tc-99m-MIBI-scintigraphy was evaluated. Patients and methods: From August 1, 1987 to December 15, 1997 453 patients were operated on for hyperparathyroidism. Preoperatively 116 patients unde rwent Tc-99m-MIBI-scanning, which had been carried out by several institute s. Results: Primary hyperparathyroidism. Sensitivity of MIBI-scintigraphy in s olitary parathyroid adenoma (n = 48) and first-time cervical exploration wa s 54% (25 true positive scans) and overall sensitivity was 50% (25 true pos itive scans in 53 patients). In 6 patients with persistence or recurrence o f primary hyperparathyroidism MIBI-scintigraphy was true positive (sensitiv ity 100%). Neither the volume nor the weight of the adenomas influenced the result of MIBI-scanning. There was no correlation between preoperative ser um concentrations of calcium and intact parathormone and sensitivity of MIB I-scintigraphy. Renal hyperparathyroidism. Before first-time cervical explo ration sensitivity of MIBI-scintigraphy (n = 40) for detecting all abnormal parathyroid glands in the presence of diffuse hyperplasia yielded only 10% . In 5 of 7 patients, who underwent reexplorations of the neck or mediastin um for persistence or recurrence of renal hyperparathyroidism MIBI-scintigr aphy was true positive (sensitivity 71%). The sensitivity for detection of hyperplastic parathyroid glands correlated with the weight as well as with the volume of the glands (p < 0.001). The weight of imaged glands ranged fr om 0.21 to 9.76 g, median 1.27 g and their median volume was 1.12 ml (range : 0.04-15.63 mi). For non imaged glands a median weight of 0.27 g and a med ian volume of 0.3 mi (ranges: 0.03 - 10.34 g, 0.009-9.8 ml, respectively) c ould be estimated. Conclusions: First-time cervical exploration for hyperparathyroidism can be carried out with a high success rate and without any preoperative localiza tion study. Before recurrent parathyroid surgery we recommend Tc-99m-MIBI-s cintigraphy because of its > 90% sensitivity.