The contribution of Tc-99 m MIBI dual phase parathyroid scintigraphy in hyperparathyroidism

The aim of this study was to evaluate the diagnostic value of double-phase Tc-99m MIBI scintigraphy for preoperative imaging of abnormal parathyroid glands, in comparison with ultrasonography and to determine the factors influencing its sensitivity and specificity.Fiftysix patients with laboratory diagnosis of hyperparathyroidism were included in this retrospective study. Parathormone, calcium, blood urea nitrogen and creatinin values of patients were recorded. Scintigraphic and ultrasonographic findings of the patients were evaluated and compared with pathology results.While the sensitivity and specificity ratios considered together, scintigraphy was found to be superior to ultrasonography in detecting adenomas. Ultrasonography was found to be superior to scintigraphy in detecting hyperplasia. Scintigraphy was more successful than ultrasonography in detecting abnormal parathyroid glands. In terms of accuracy, positive predictive value and negative predictive value in detecting adenomas and abnormal parathyroid glands, scintigraphy showed a marked superiority to ultrasonography. But in terms of accuracy, positive predictive value and negative predictive value in detecting hyperplasia, ultrasonography had better rates. In addition, the sensitivity of scintigraphy in elder age group in detecting adenomas and abnormal parathyroid glands was found to be lower than that of younger age group.Our study showed that double-phase Tc-99m MIBI scintigraphy was more sensitive than ultrasonography in imaging adenomas and abnormal parathyroid glands. But in detecting hyperplasia, ultrasonography was seen to be superior. The complementary role of ultrasonography to scintigraphy in preoperative imaging in patients with primary hyperparathyroidism becomes even more important in elderly patients, because of the low sensitivity of scintigraphy in demonstrating the abnormal parathyroid glands in elder age group.