| Abstract: | Objective: To evaluate the diagnostic efficacy of CT in differentiating adrenal adenomas from malignant tumors. Methods: 124 patients with 147 adrenal adenomas and malignant tumors were analyzed. Tumor size, margin, internal structure and the relation of the tumor to the adrenal gland were investigated with CT. Both precontrast and postcontrast CT attenuation values of the tumor were measured and the enhanced degree was calculated respectively. CT pixel mapping of the tumor was done in 20 patients. Results were analyzed by using ROC curve. Results: The area under the ROC curve for precontrast CT attenuation values (0.91(0.05) was significantly larger than that for postcontrast CT attenuation values (0.83(0.04), enhanced degree (0.74(0.08) or tumor sizes (0.82(0.04). With a threshold of tumor size(3.0 cm, homogenous density, precontrast CT attenuation value(20 HU, postcontrast CT attenuation value(35 HU or enhanced degree(20 HU, the sensitive for characterizing adenomas were 86%, 85%, 88%, 76% and 74%, and the specificity were 73%, 72%, 91%, 78% and 61% respectively. Connection with normal adrenal gland (68%), precontrast CT attenuation value<0 HU (17%), and area of slightly negative CT attenuation value on CT pixel mapping were only seen in adrenal adenomas, whereas poorly defined margin and/or invasion of surrounding structures (30%), irregular thick rim enhancement (22%) were characteristic of malignant tumors. The overall correspondence rate with final diagnosis was 92.7% in our group. Conclusion: Most of the adrenal adenomas and malignant tumors can be distinguished by comprehensive analysis of CT features. |
