The Role of Tumor-Seeking Radiopharmaceuticals in the Diagnosis and Management of Adrenal Tumors

Abstract

Context.The variety of tumor-seeking radiopharmaceuticals, which are currently in clinical use, may have a potential role as imaging agents for adrenal gland tumors, due to physiological characteristics of this organ.Objective. The purpose of this study was to evaluate the diagnostic potential of 99m Tc-HYNIC-TOC, 99m Tc(V)-DMSA, and 99m Tc-MIBI in the assessment of adrenal tumors, by correlating with imaging findings and histopathologic results.Design. The research is designed as a crosssectional prospective study.Patients and method. The study included 50 patients with adrenal tumors (19 hormone-secreting and 31 nonfunctioning) and 23 controls without adrenal involvement. In all patients, single-photon emission computed tomography (SPECT) was performed, using qualitative and semiquantitative analysis. The tumor to nontumor tracer uptake was conducted by using a region-ofinterest technique. Adrenal to background (A/B) ratio was calculated in all cases.Results. 99m Tc-HYNIC-TOC scintigraphy showed a high statistical significance between A/B ratios, while other two tracers resulted in a lower sensitivity, specificity and accuracy. Futhermore, 99m Tc-HYNIC-TOC could have a high diagnostic yield to detect adrenal tumors (the receiveroperating-characteristic curve analysis, A/B ratio cut-off value of 8.40). Conclusion.A semiquantitative SPECT analysis showed that 99m Tc-HYNIC-TOC is a highly sensitive tumorseeking agent for the accurate localization of adrenal tumors.

Can MDCT Enhancement Patterns Be Helpful in Differentiating Secretory from Non-Functional Adrenal Adenoma?

“…Adrenal scintigraphy using 99m Tc-HYNIC-TOC is an SSTR-based imaging method, equal or superior to other conventional imaging methods. Encouraged by the results of various studies somatostatine radiolabeled analog 99m Tc-HYNIC-TOC has a high sensitivity in localizing adrenal tumors, while the visualization of functional adrenal masses remains controversial [15,41]. In the present study, we showed statistically significant positive diagnostic potential for detecting the existence of Ats and the functional active form of these tumors as well.…”

“…MDCT examination is more frequently used, with a prevalence varying between 0.35% and 9% in different series, while MRI remains a second-level technique. The expense, the duration of examination, which is very demanding for the patient, as well as the appearance of artifacts caused by physiological processes in the abdomen, are cited as the main limiting factors [11][12][13][14][15]. The most important MRI technique is Chemical-shift which can be used to distinguish adenomas from non-adenomas.…”

“…According to comparative radiology studies, radionuclide imaging has a complementary and increasingly important role in characterizing adrenal lesions [15].…”

“…Scintigraphy with the somatostatin analog tyrosine3-octreotide labeled with the radioactive isotope Tc-99m ( 99m Tc-HYNIC-TOC) has an affinity for tumors expressing somatostatin receptors. 99m Tc-HYNIC-TOC has high sensitivity and specificity and enables precise localization of expansive changes in the adrenal glands [15].…”