Value Of Metahydroxyephedrine PET Diagnose In Pheochromocytoma

Objective: Pheochromocytomas are rare tumors of chromaffin cells for which the optimal management is surgical resection. Precise diagnosis and localization may be elusive. We evaluated whether positron emission tomography(PET)scanning with the norepinephrine analogue11C-metahydroxyephedrine (mHED) would allow more exact diagnosis and localization.Methods:Thirty-one patients with adrenal tumor or suspected enlargement were evaluated by anatomical imaging (computed tomography or magnetic resonance imaging), most of those were suspected pheochromocytoma. PET imaging was performed by using mHED with dynamic adrenal imaging in all patients, followed by a torso survey. Images were evaluated qualitatively by an experienced observer.Results:Twenty-two patients had pathology-confirmed adrenal pheochromocytoma, one was left retroperitoneal pheochromocytoma, one was bladder pheochromocytoma. Of the other seven, one patient was diagnosed as adrenal cortical adenoma afer surgery, two patients were confirmed pathologically adrenal cortical hyperplasia, two patients were adrenal medullary hyperplasia pathological and the other two had normal feature in mHED-PET without undergone surgery. In Twenty-four patients with pheochromocytoma, The mHED-PET detected21sites of confirmed disease and abnormally increased metabolism. Two patients with adrenal medullary hyperplasia had a positive mHED-PET scan of abnormal metabolism. Of the other five patients, mHED-PET detected normal metabolism, MHED-PET scanning aided the decision not to operate in two of these five patients.Conclusions:mHED-PET scanning for adrenal tumors or suspected hyperplasia or ectopic pheochromocytomas offers improved sensitivity and specificity over current diagnostic approaches. MHED-PET may significantly influence the clinical management of patients with a suspicion of these tumors and warrants further investigation.