X-ray and Radionuclide Imaging in the Diagnosis of ACTH-Producing Neuroendocrine Tumors

Abstract

Ectopic ACTH syndrome caused by excessive production of adrenocorticotropic hormone (ACTH) by a neuroendocrine tumor (NET) is an extremely rare disease, the main manifestation of which is pronounced hypercortisolism. In order to avoid the development of life-threatening complications and disability of the patient, timely topical diagnosis and rapid decision-making on further management tactics are necessary. The problem of the diagnosis of NET and differential diagnosis with other formations remains relevant and one of the little-studied. Despite the existing wide arsenal of methods of conventional diagnostics, functional and receptor imaging, the source of the disease remains unidentified in about 20% of patients. This article discusses the modern possibilities of NET visualization using conventional and radionuclide imaging methods, demonstrates the diagnostic capabilities of somatostatin-receptor scintigraphy and single-photon emission computed tomography combined with computed tomography (SPECT/CT) and combined positron emission and computed tomography (PET/CT) in the visualization of NET producing ACTH, and analyzes existing radiopharmaceuticals.