Endocrine radionuclide scintigraphy with fusion single photon emission computed tomography/computed tomography.

Aim: To review the benefits of single photon emission computed tomography (SPECT)/computed tomography (CT) hybrid imaging for diagnosis of various endocrine disorders.

Methods: We performed MEDLINE and PubMed searches using the terms: "SPECT/CT"; "functional anatomic mapping"; "transmission emission tomography"; "parathyroid adenoma"; "thyroid cancer"; "neuroendocrine tumor"; "adrenal"; "pheochromocytoma"; "paraganglioma"; in order to identify relevant articles published in English during the years 2003 to 2015. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts (case reports, reviews, meta-analyses and abstracts) concerning the application of SPECT/CT to endocrine imaging were analyzed to provide a descriptive synthesis of the utility of this technology.

Results: The emergence of hybrid SPECT/CT camera technology now allows simultaneous acquisition of combined multi-modality imaging, with seamless fusion of three-dimensional volume datasets. The usefulness of combining functional information to depict the bio-distribution of radiotracers that map cellular processes of the endocrine system and tumors of endocrine origin, with anatomy derived from CT, has improved the diagnostic capability of scintigraphy for a range of disorders of endocrine gland function. The literature describes benefits of SPECT/CT for (99m)Tc-sestamibi parathyroid scintigraphy and (99m)Tc-pertechnetate thyroid scintigraphy, (123)I- or (131)I-radioiodine for staging of differentiated thyroid carcinoma, (111)In- and (99m)Tc- labeled somatostatin receptor analogues for detection of neuroendocrine tumors, (131)I-norcholesterol (NP-59) scans for assessment of adrenal cortical hyperfunction, and (123)I- or (131)I-metaiodobenzylguanidine imaging for evaluation of pheochromocytoma and paraganglioma.

Conclusion: SPECT/CT exploits the synergism between the functional information from radiopharmaceutical imaging and anatomy from CT, translating to improved diagnostic accuracy and meaningful impact on patient care.