Ces radiol. 2008, 62(1):34-43

Adrenal incidentalomas: spectrum of histologic diagnoses and CT findingsOriginal article

Filip Čtvrtlík¹, Miroslav Heřman¹, Vlastislava Tichá², Vladimír Študent³

¹ Radiologická klinika FN, Olomouc

² Oddělení klinické patologie FN, Olomouc

³ Urologická klinika FN, Olomouc

Aim: To summarize typical CT features of incidentally found adrenal masses and to compare literature resources with our own experience as well as to create image database of typical CT findings.

Method: Retrospective study of incidentally found adrenal masses was performed among the subjects operated at the University Hospital in Olomouc between 2003 and 2007. The study group consists of 62 histologically confirmed masses: adrenocortical carcinomas (n = 4), metastases (n = 7), adenomas (n = 37), pheochromocytomas (n = 9), myelolipomas (n = 2) and others (n = 3). Following CT signs were observed: size, shape, demarcation, homogeneity, density before and after contrast agent injection, central hypodensity, presence of calcifications and fat. Statistical analysis was performed by chi-square test, Kruskal-Wallis test, and Mann-Whitney test. For differences among groups, two tailed t-test was used. For assessment of maximum size, mean size, and volume of the mass, regression analysis was used.

Results: Correlation and regression analysis showed that maximum size, mean size, and volume of the mass well correlate with high determination coefficient (0.96-0.99). Sensitivity, specificity, accuracy, positive and negative predictive values for distinguishing adenomas from non-adenomas with the size of 41.5 mm were as follows: 81.1%, 70.0%, 77.2%, 83.3%, 66.7%; using non-contrast density of 23 HU: 89.2%, 100%, 93.0%, 100%, 83.3%; using post contrast density of 47.5 HU: 80.6%, 100%, 88.2%, 100% 76.9%; using post contrast density increase of 34.5 HU: 74.2%, 70.0%, 72.5%, 79.3%, 63.6%, respectively. ROC showed that the most accurate parameter determining adenomas from non-adenomas is the native density. Post contrast density values are less accurate. The least accurate parameters were: size of the lesion and density increase.

Conclusion: Routine CT of abdomen gives sufficient results for adrenal masses diferentiation (regarding surgical treatment, conservative treatment, or regular follow-up).

Keywords: adenoma, pheochromocytoma, incidental findings, carcinoma, metastasis, adrenal glands, computed tomography

Accepted: January 3, 2008; Published: March 1, 2008  Show citation