[Novel imaging techniques for the differential diagnosis of adrenal tumors, pheochromocytomas and paragangliomas].

[BACKGROUND] Molecular imaging of adrenal tumors has become established in clinical routine, because they often cannot be characterized using morphological imaging alone. It can provide an important contribution to the localization and characterization of these lesions.

[OBJECTIVES] The use of various radiopharmaceuticals forms the basis of molecular imaging via positron emission tomography (PET)/computed tomography (CT) and single photon emission computed tomography (SPECT)/CT.

[MATERIALS AND METHODS] We conducted a literature search on established and novel PET- and SPECT-tracers used in adrenocortical tumors, pheochromocytomas, and paragangliomas.

[RESULTS] For distinguishing adrenocortical carcinomas from adenomas imaging of glucose metabolism using [F]FDG-PET/CT (FDG: fluorodeoxyglucose) is helpful. CXC chemokine receptor type 4 (CXCR4)-targeting radioligands like [Ga]Ga-PentixaFor show good sensitivity for detection in primary hyperaldosteronism and are subject to clinical trials. In various studies, [C]metomidate PET/CT demonstrated high specificity and high sensitivity in the identification of unilateral aldosterone-producing adenomas in patients compared to invasive adrenal vein catheterization (AVS) and can be used as an alternative. PentixaFor PET/CT also demonstrated high sensitivity and specificity for the diagnosis of cortisol-producing adenomas in studies. Molecular imaging of pheochromocytomas and paragangliomas utilizes the uptake of catecholamine analogues or metabolites, [18F]F-DOPA, or somatostatin receptor expression.

[CONCLUSION] Molecular imaging can make an essential contribution to the noninvasive diagnosis of adrenal tumors, pheochromocytomas, and paragangliomas by visualizing various metabolic processes.