To investigate the differential diagnostic value of CT scan minimum attenuation values（minAVsCT）in adrenal adenomas and non-adenomas.

CT scan data of 89 cases of clinical and pathologically confirmed adrenal adenomas were subjected to retrospective analysis and compared with data of 46 cases involving 50 non-adenomas（25 metastases, 20 pheochromocytomas, 3 lymphomas, and 2 cortical carcinomas）. The distributions of mean attenuation values（meanAVs）≤10 Hu and minAVs≤0 Hu and CT histogram analysis with ≥10% negative pixels were observed in adrenal adenomas and non-adenomas, and the diagnostic sensitivity and specificity of these 3 methods for adenomas were calculated.

The distributions of unenhanced meanAVs≤10 Hu, minAVs≤0 Hu, and CT histogram analysis with ≥10% negative pixels among cases of adenoma and non-adenoma were 62.9%（56/89）and 0%（0/50）（χ²=52.687, P=0.000）, 84.3%（75/89）and 2%（1/50）（χ²=83.917, P=0.000）, and 77.5%（69/89）and 0%（0/50）（χ²=83.917, P=0.000）, respectively. The respective diagnostic sensitivities, specificities, false negative rate（FNR）, false positive rate（FPR）, positive predictive value（PPV）, negative predictive value（NPV）and accuracy of these 3 methods for adenomas were 62.9% vs 84.3% vs 77.5%, 100% vs 98.0% vs 100%, 37.1% vs 15.7% vs 22.5%, 0 vs 2% vs 0, 100% vs 98.7% vs 100%, 60.2% vs 77.8% vs 71.4%, and 76.3% vs 89.2% vs 85.6%.

Although the specificity and PPV of minAVs≤0Hu is slightly less than meanAVs≤10Hu and CT histogram analysis with ≥10% negative pixels, it exhibits the best sensitivity and accuracy with a simple operation, and is thus suitable for clinical application.