SPECT/CT Fusion in the Diagnosis of Hyperparathyroidism

OBJECTIVES In this study, we aimed to analyze the relationship between the diagnostic ability of fused single photon emission computed tomography/ computed tomography (SPECT/CT) images in localization of parathyroid lesions and the size of adenomas or hyperplastic glands. METHODS Five patients with primary hyperparathyroidism (PHPT) and 4 patients with secondary hyperparathyroidism (SHPT) were imaged 15 and 120 minutes after the intravenous injection of technetium99m-methoxyisobutylisonitrile ((99m)Tc-MIBI). All patients underwent surgery and 5 parathyroid adenomas and 10 hyperplastic glands were detected. Pathologic findings were correlated with imaging results. RESULTS The SPECT/CT fusion images were able to detect all parathyroid adenomas even with the greatest axial diameter of 0.6 cm. Planar scintigraphy and SPECT imaging could not detect parathyroid adenomas with an axial diameter of 1.0 to 1.2 cm. Four out of 10 (40%) hyperplastic parathyroid glands were diagnosed, using planar and SPECT imaging and 5 out of 10 (50%) hyperplastic parathyroid glands were localized, using SPECT/CT fusion images. CONCLUSION SPECT/CT fusion imaging is a more useful tool for localization of parathyroid lesions, particularly parathyroid adenomas, in comparison with planar and or SPECT imaging.