Computed tomography and magnetic resonance imaging features for differentiating functioning from non-functioning adrenal lesions

Abstract

Aim: It is not well known whether the radiological features of adenomas differ between functioning and non-functioning adrenal lesions (NFAL). The aim of this study was to evaluate the characteristic features of computed tomography (CT) and magnetic resonance imaging (MRI) characteristics among functioning and non-functioning adrenal lesions. Material and Methods: This retrospective study included 89 patients with functioning adrenal lesions and 148 patients with NFAL, whose CT or MRI findings were present. Group 1 included patients with functioning adrenal lesions and group 2 patients with NFAL. Results: In patients with functioning adrenal mass, adenoma size (p:0.001), unenhanced and early-enhanced Hounsfield units (HU) (p<0.001) were significantly higher compared to those with NFAL. Among the patients with functioning adrenal mass; Cushing’s syndrome, pheochromocytoma and primary hyperaldosteronism were diagnosed in 34, 32 and 23 patients, respectively. Mean earlyenhanced HU was higher in all functioning groups compared to NFAL (p<0.001, all). ROC analysis showed 80% specificity and 82.7% sensitivity for determining functioning adrenal masses with an early-enhanced CT attenuation value of 27 HU. On T1-weighted images functioning adrenal lesions were more commonly hypointense than NFAL (p=0.02). Conclusion: This study reveals that functioning adrenal lesions might be differentiating from NFAL using CT features. Especially early-enhanced CT attenuation, which is elevated in all functioning adrenal mass forms, may be used effectively for this purpose.