Use Quantitative CT Texture Analysis To Identify Adrenal Tumors

ObjectiveTo investigate the feasibility of using CT texture analysis to differentiate amonglipid-poor adrenal adenoma,pheochromocytoma and adrenal metastases.Methods1.66 lipid-poor adrenal adenoma,98 pheochromocytoma and 101 adrenal metastases lesions were analyzed retrospectively.All the patients had abdominal non-enhanced CT and adrenal enhanced CT scans.We used TexRAD software to analyzed the texture features of CT images and compared the differences in each texture parameter among three adrenal lesions.Results1.On non-enhanced CT images,there were significant differences in Mean and Kurtosis at all the texture scales(SSF0-6)among the three types of adrenal lesions(P<0.05),as well as SD at fine and coarse texture scale(SSF2,6)(P<0.05).Entropy(SSF0-3,5-6)and MPP(SSF0-2,4-6)were significantly lower in lipid-poor adrenal adenoma and adrenal metastases than that in pheochromocytoma(P<0.05).There were significant differences in Skewness(SSF0-3)among three types of lesions,which was lowest in pheochromocytoma and highest in adrenal metastases.2.On enhanced CT images,Mean,SD,Entropy and MPP showed significantly differences among the three types of adrenal lesions at all the texture scales(SSF0-6)(P<0.05),which were all highest in pheochromocytoma and lowest in adrenal metastases.Skewness(SSFO)and Kurtosis(SSF0,2)were significantly lower in adrenal metastases than that in lipid-poor adrenal adenoma and pheochromocytoma(P<0.05).Conclusions There are significant differences in CT texture analysis parameters among lipid-poor adrenal adenoma,pheochromocytoma and adrenal metastases.CT texture analysis has potential clinical application values in differentiating these three adrenal lesions.ObjectiveTo determine whether quantitative CTTA can be used to differentiate metastases from benign adrenal masses on single energy CT images.Material and MethodsA total of 225 patients with 265 histologically confirmed adrenal masses(101 metastases,98 pheochromocytomas,and 66 lipid-poor adenomas)were included in this retrospective study.CTTA was performed and six texture parameters(including mean,SD of pixel distribution histogram,mean of positive pixels,entropy,kurtosis,skewness)across six spatial scaling factor(SSF)were recorded on both unenhanced and contrast-enhanced CT images.Receiver operating characteristic(ROC)analysis was performed and the area under the ROC curve(AUC)was calculated using the significant texture parameters for the objective.Diagnostic performance was evaluated using the cut-off values of texture parameters by ROC analysis.The optimal discriminative texture parameters were used to produce support vector machine(SVM)classifiers.Diagnostic accuracy and 10-fold cross-validation was performed.ResultsCompared to benign adrenal masses,metastases had significantly lower mean gray-level intensity,SD,entropy,mean of positive pixels and kurtosis on unenhanced images(P<0.0083).On contrast-enhanced CT images,except for skewness and kurtosis,the other four texture texture-quantifiers were lower in the metastatic compared to the other group(P<0.0083).A model incorporating mean,SD,entropy and mean value of positive pixels produced an AUC of 0.85±0.03 with an SVM accuracy of 77%to identify metastatic from benign adrenal masses.ConclusionDifferentiation of metastatic and benign adrenal masses can be achieved accurately with CTTA on contrast-enhanced CT images.