| Objective To investigate whether combined assessment of unenhanced and portal venous phase CT can distinguish between lipid-poor adrenal adenoma and metastatic tumor. Materials and Methods Retrospectively analyzed the clinical and imaging data of 42 patients with adrenal lipid-poor adenoma and 43 patients with adrenal metastases confirmed by clinical follow-up or surgical pathology at our hospital during the period of January 2018 to December 2022, The gender, age, hypertension, history of tumor, tumor distribution, morphology, cystic changes, and calcification of the two groups of tumors were analyzed, and measured and calculated the size, long and short diameters of the lesions, as well as the the unenhanced and contrast-enhanced attenuation, the absolute enhancement , and relative enhancement ratio of the lesions. Binary logistic regression analysis was used to screen the independent risk factors of the two groups of tumors, and then receiver operating characteristic curve (ROC) analysis was performed to compare the diagnostic efficacy of each factor. Results In the clinical data of the two groups of tumors, the differences between gender, age, hypertension, and tumor history were statistically significant (P < 0.01); in the categorical variable data of the two groups of tumors, the differences in tumor distribution, morphology, and cystic changes were statistically significant (P < 0.01), and the differences in calcification were not statistically significant (P > 0.05); and in the CT continuous variable data of the two groups of tumors, the differences in the unenhanced attenuation, contrast-enhanced attenuation, absolute enhancement , relative enhancement ratio, size and long diameter of the lesion were statistically significant (P < 0.05), while the difference in the short diameter of the lesion between the two groups was not statistically significant (P > 0.05); binary logistic regression analysis showed that age, unenhanced attenuation, and contrast-enhanced attenuation were the independent risk factors for the diagnosis of lipid-poor adenoma, with odds ratios of 1.135 , 1.554，0.828 ; ROC curve analysis showed that when the relative enhancement ratio was greater than the threshold value of 169%, the area under the curve (AUC), sensitivity, and specificity for diagnosing lipid-poor adenoma were 0.982 , 88%, and 98%, respectively; for unenhanced attenuation <26.5 HU, the AUC, sensitivity, and specificity were 0.820 , 86%, and 73.8%, respectively; Conclusion The relative enhancement ratio threshold of 169% for unenhanced and portal venous phase CT can distinguish adrenal lipid-poor adenoma and metastases more accurately, especially for lesions with unenhanced attenuation of 10-30 HU. |
