Optimal diagnosis of adrenal masses

IntroductionMost adrenal gland lesions are detected by CT; however some patients are referred for MRI and PET CT, with percutaneous biopsy as the last resort.Aim of studyTo provide the role of various imaging modalities for optimal assessment of adrenal masses. Furthermore we would like to recommend a diagnostic algorithm.Patient & methodsWe studied 29 patients with 29 adrenal masses (11 adenomas, 6 metastases, 5 myelolipomas, 4 adrenocortical carcinomas, 2 pheochromocytoma & 1 cyst). CT scan was done with a dedicated adrenal CT protocol. Washout characteristics were then assessed. MRI was done in 19 patients. Qualitative assessment of the chemical shift images was done in 11 patients. Five patients underwent PET and PET CT.ResultsIn CT: a mean absolute percentage washout of 83% and 41.4% while a mean relative percentage washout of 57.4% and 17.95% were found for adenomas and metastases respectively. In MRI: adenomas showed signal drop on out of phase sequences compared to in phase sequences while metastases did not. In PET CT: mean maximum SUV uptake for adrenal metastases was 7.5 compared to 2.1 in adenoma.ConclusionOur results confirm the evolving role of CT in detection and characterization of an adrenal mass. Further assessment by MRI & PET CT can be beneficial.