CT-MIBI-SPECT image fusion predicts multiglandular disease in hyperparathyroidism

To perform focused or minimally invasive surgery for hyperparathyroidism (HPT) exact preoperative localization is mandatory. Computed tomography-Tc-99m-sestamibi-single photon emission computed tomography image fusion (CT-MIBI-SPECT) serves this difficult task in single gland HPT to a large extent. The aim of this study was to evaluate whether CT-MIBI-SPECT image fusion is superior to MIBI-SPECT alone and CT alone in detecting abnormal parathyroid tissue in patients with multiglandular disease. CT-MIBI-SPECT image fusion for preoperative localization was performed in 30 patients with multiglandular disease. There were six patients with primary hyperparathyroidism (four MEN I syndromes and two double adenomas; one of these patients has HRPT2 gene mutation), 14 with secondary, and eight with tertiary HPT, further one patient each suffering from persistent primary and persistent secondary hyperparathyroidism. In both persistent patients only one remaining gland was left from primary surgery. The results of MIBI-SPECT, CT, and CT-MIBI-SPECT image fusion were compared in these patients. The outcome and the exact predicted positions were correlated with intraoperative findings. In five out of six patients with multiglandular primary hyperparathyroidism more than one gland was detected, thus multiglandular disease could be suspected preoperatively. Overall CT-MIBI-SPECT image fusion was able to predict the exact position of all abnormal glands per patient in 14 of 30 (46.7%) cases, whereas CT alone was successful in 11 (36.7%), and MIBI-SPECT alone just in four (13.3%) of 30 patients. Multiglandular disease in primary hyperparathyroidism can be suspected preoperatively in a high percentage of patients. Additionally, this study shows that CT-MIBI-SPECT image fusion is superior to CT or MIBI-SPECT alone in preoperative localization of all pathologic glands in patients suffering from multiglandular disease.