Parathyroid glands: Combination of Tc-99m MIBI scintigraphy and US for demonstration of parathyroid glands and nodules

PURPOSE: To determine the appropriate choice of imaging techniques for loca lization of nodular lesions of parathyroid glands. MATERIALS AND METHODS: First, computed tomographic (CT), magnetic resonance (MR), ultrasonographic (US), and technetium 99m methoxyisobutyl-isonitrile (MIBI) scintigraphic images in 49 patients with primary hyperparathyroidis m were retrospectively evaluated. A single-blind, prospective study that in cluded 16 patients with primary hyperparathyroidism was then conducted. MR, US, scintigraphic, and color Doppler US images of the neck were obtained a nd analyzed. RESULTS: in the retrospective study, CT, MR imaging, and US had low sensiti vity (13%, 17%, and 27,respectively) and specificity (39%, 65%, and 65%, re spectively). Scintigraphy had 57% sensitivity and 85% specificity. In the p rospective study, the use of latest-generation MR and US equipment and the participation of experienced operators led to improved sensitivity and spec ificity for these techniques. The combination of US and scintigraphy result ed in improved sensitivity (96%), specificity (83%), and positive and negat ive predictive values (88% and 94%, respectively), relative to the results obtained with either method alone. Doppler US was of little help in the set ting of small glands. CONCLUSIONS: The combination of Tc-99m MIBI scintigraphy and US performed b y well-trained operators with up-to-date instruments appeared to be the bes t diagnostic tool for the preoperative diagnosis of parathyroid disease.