Value of combined CT parameters in distinguishing benign from malignant adrenal masses in cancer patients

The aim of this work was to evaluate the effectiveness of combined CT parameters in distinguishing benign from malignant adrenal masses in cancer patients.The study included 33 patients with 39 adrenal masses. CT protocol included pre-contrast scan, dynamic and delayed contrast-enhanced scans assessing the mass size, pre-contrast attenuation, histogram & post-contrast absolute percentage washout (APW). Sensitivities, specificities, accuracies & P-values were calculated for individual and combined parameters.Adrenal masses included 13 lipid rich, nine lipid poor adenomas, one carcinoma and 16 metastases. Size was accurate in the differentiation of 26 of the total 39 masses (66.7%). Accuracy (82.05%) & specificity (68.18%) for the 10% negative pixels threshold on histogram were higher as compared to 76.9% & 59% for the 10 HU mean attenuation threshold. Using APW of 55% at 10 min delay, a sensitivity of 88.23%, a specificity of 86.36% & an accuracy of 87.17% were calculated. The combination of pre-contrast attenuation & histogram values and the APW were highly significant for the differentiation of benign & malignant adrenal masses (P-value is <0.001).Combining the CT parameters including the pre-contrast attenuation values, histogram & the post-contrast washout analysis yielded a powerful diagnostic protocol with 74.3% accuracy, excluding the size parameter.