Use of pinhole dual-phase Tc-99m sestamibi vs combined Tc-99m sestamibi and Tc-99m pertechnetate scintigraphy in patients with hyperparathyroidism where single-photon emission computed tomography/computed tomography is unavailable.

Objective: To compare the sensitivity and positive predictive value (PPV) of pinhole dual-phase Tc-99m sestamibi vs combined Tc-99m sestamibi and Tc-99m pertechnetate scintigraphy in patients with hyperparathyroidism where single-photon emission computed tomography (SPECT)/CT is unavailable.
Methods: All patients with biochemically proven hyperparathyroidism who underwent both pinhole Tc-99m sestamibi and Tc-99m pertechnetate scintigraphy between January 2012 and December 2017 with surgery performed within 3 months of imaging were analyzed. Tc-99m sestamibi images alone and combined with Tc-99m pertechnetate images were interpreted by two nuclear medicine physicians. The sensitivity and PPV of the two imaging approaches were determined based on the surgical findings.
Results: Of the 38 patients included, surgery revealed 33 single parathyroid adenomas (PA), one double adenoma and four parathyroid hyperplasia (PH). On a per-patient basis, the sensitivity and PPV for detection of PA or PH were 76% and 100%, respectively, with Tc-99m sestamibi alone vs 84% and 100% using the combined approach. For PA, the sensitivity and PPV were 82% and 100%, respectively, with Tc-99m sestamibi alone vs. 91% and 100% with the combined approach. PH was identified in only one of four patients with Tc-99m sestamibi alone or in combination. There were no significant differences in sensitivity (P = 0.08) and PPV (P > 0.99) between Tc-99m sestamibi alone and Tc-99m sestamibi with Tc-99m pertechnetate.
Conclusion: Pinhole dual-phase Tc-99m sestamibi alone has high accuracy in the detection of PA. The routine addition of Tc-99m pertechnetate to Tc-99m sestamibi does not result in significant improvement in the detection of PA or PH and should be reserved for equivocal cases.