99m TcO 4 - / 99m Tc-MIBI dual-tracer scintigraphy for preoperative localization of parathyroid adenomas.

OBJECTIVE: To investigate the accuracy of dual-tracer scintigraphy for locating parathyroid adenomas in patients with primary hyperparathyroidism (PHPT).

METHODS: We reviewed 268 patients with PHPT. All patients underwent technetium-99m pertechnetate (99m TcO4 - ) scintigraphy and technetium-99m methoxyisobutylisonitrile (99m Tc-MIBI) dual-tracer scintigraphy of the thyroid and parathyroid glands, respectively. 99m TcO4 - planar scintigraphy was carried out initially followed by dual-phase 99m Tc-MIBI single-photon emission computed tomography (SPECT)/CT the next day. The findings were combined and interpreted. Individual 99m Tc-MIBI and dual-tracer scintigraphy were both analyzed. The sensitivity, specificity, and accuracy were determined in relation to surgical findings. The average interval between scan and surgery was 13 days.

RESULTS: The positive and negative predictive values of 99m Tc-MIBI SPECT/CT were 92.0% and 71.3%, respectively, and the sensitivity, specificity, and accuracy were 88.3%, 79.2%, and 85.8%, respectively. The positive and negative predictive values of dual-tracer scintigraphy were 96.3% and 82.3%, respectively, and the sensitivity, specificity, and accuracy were 92.9%, 90.3%, and 92.2%, respectively. Youden's index for dual-tracer scintigraphy and 99m Tc-MIBI SPECT/CT were 0.83 and 0.63, respectively.

CONCLUSIONS: These finding suggest that 99m TcO4 - and 99m Tc-MIBI dual-tracer scintigraphy is more accurate than other scintigraphy methods for detecting parathyroid adenoma, and may thus be the most suitable imaging technique in patients with PHPT.