Analysis of MDCT Findings in the Differentiation of Adrenal Masses in Lung Cancer Patients in Siriraj Hospital

Abstract

Objective: To determine significant multi-detector CT (MDCT) features that may differentiate adrenal metastasis from
adrenal adenoma in lung cancer patients.
Methods: We retrospectively analyzed CT images of 52 patients (72 adrenal masses) with history of lung cancer, from January
2005 to September 2010. Two radiologists independently evaluated size, unenhanced and enhanced attenuation, homogeneous
or inhomogeneous density, calcification, patterns of involvement, number, unilateral or bilateral sides of the adrenal masses.
The nature of these adrenal masses were determined by follow-up CT scans for at least 6 months. Associations between CT
characteristics and the nature of these adrenal masses were interpreted.
Results: 22 of these adrenal masses were adenomas and 50 were metastases. CT features that show statistically significant
help in differentiating between these two entities were density in non-contrast, post-contrast enhancement, patterns of involvement,
and calcification. Differentiations of adenoma from adrenal metastasis by using the unenhanced attenuation criterion
(≤ 10 HU), yielded 50% sensitivity, 100% specificity, and 84% accuracy. Patterns of involvements yielded 58% sensitivity
and 90.9% specificity.
Conclusion: We found attenuation on unenhanced CT (≤ 10 HU) and the pattern of involvement (diffuse nodular infiltration
along body and limbs) of adrenal masses are helpful in differentiating adrenal adenoma and adrenal metastasis in lung cancer
patients with high specificity.