Scintigraphic studies in adrenal hypertension

Area of Science:

• Endocrinology and Nuclear Medicine
• Diagnostic Imaging of Adrenal Gland Disorders

Background:

• Endocrine hypertension secondary to adrenal disorders is uncommon but treatable, often affecting younger patients and sometimes exhibiting familial patterns.
• Accurate biochemical diagnosis and lesion localization are crucial for effective management and potential surgical cure.

Purpose of the Study:

• To review the role of adrenal scintigraphy in characterizing hypersecretory adrenal disorders causing hypertension.
• To highlight the utility of specific radiopharmaceuticals in localizing adrenal cortex and sympathoadrenal dysfunction.

Main Methods:

• Utilized (131)I-6 beta-iodomethyl-19-norcholesterol (NP-59) to assess adrenocortical cholesterol uptake.
• Employed (131)I- and (123)I-metaiodobenzylguanidine (MIBG) as norepinephrine analogs for sympathoadrenal imaging.
• Examined dexamethasone suppression NP-59 adrenal scintigraphy for differentiating adrenal adenoma and hyperplasia.

Main Results:

• NP-59 uptake patterns and levels accurately depict adrenal dysfunction and hyperfunction in Cushing's syndrome, aiding localization even when CT fails.
• Dexamethasone suppression NP-59 scintigraphy demonstrates high sensitivity and specificity, outperforming CT in distinguishing adenoma from bilateral hyperplasia in primary aldosteronism.
• MIBG effectively localizes pheochromocytoma and screens for multiple, extra-adrenal, recurrent, or metastatic lesions, and assesses neuroblastoma metastasis.

Conclusions:

• Adrenal scintigraphy with NP-59 and MIBG is a valuable tool complementary to anatomical imaging for localizing functioning adrenal diseases and related neoplasms.
• These nuclear medicine techniques are essential for accurate diagnosis and management of various adrenal hypersecretory disorders leading to hypertension.