ABSTRACT
Objective To evaluate the diagnostic value of ~(99)Tc~m-methoxyisobutylisonitrile (MIBI) SPECT scintigraphy combined Iocalizable CT in the localization of ectopic parathyroid glands in hyperparathyroidism.Methods Retrospective data of surgery,pathology and imaging were collected from 28 patients with hyperfunctioning ectopic parathyroid glands.All cases underwent CT studies.Twenty-five patients had ~(99)Tc~m-MIBI planar imaging first:SPECT scintigraphy combined localizable CT was performed for the patients with abnormal radionuclide foci immediately.The fusion images obtained after reconstruction showed the exact location of the ectopic foci.Operative histopathologic results were regarded as "gold standards".Presuming 4 parathyroid glands as normal findings,findings confirmed by operation and pathology were regarded as positive,otherwise negative.The results of CT and radionuclide imaging were compared by X~2-test of four-foId table.Results Twenty-eight ectopic parathyroid glands were found in 28 patients,all pathologically confirmed as adenomss.CT found 22 foci,of which 17 were true positive,5 false positive,11 false negative,and 79 true negative.~(99)Tc~m-MIBI SPECT scintigraphy combined localizable CT found 23 foci,no false positive,2 false negative,and 75 true negative.The results showed that the sensitivities were 61% (17/28),92%(23/25),specificities 94%(79/84),100%(75/75),accuracies 86%(96/112),98% (98/100),positive predictive values 77%(17/22),100%(23/23),and negative predictive values 88% (79190),97%(75/77),respectively,for CT and radionuclide imaging.~(99)Tc~m-MIBI SPECT scintigraphy combined localizable CT was therefore significantly higher than CT in sensitivity(X~2=6.98,P＜0.01),specificity (X~2=4.61,P＜0.05),accuracy (X~2=10.30,P＜0.01),positive predictive value(X~2=5.88,P＜0.05) and negative predictive value (X~2=5.36,P＜0.05).Conclusion ~(99)Tc~m-MIBI SPECT scintigraphy combined localizable CT is superior to CT alone in the localization of ectopic parathyroid glands in hyperparathyroidism,but false negative can be found in some patients.