RESUMO
Objective To evaluate the diagnostic performance of enhancement value and morphological features by using mul-tiphasic MDCT on differentiating untypical T4a from T3 gastric cancer.Methods Fifty-one histopathologically proven T3 and T4a gastric cancer patients with smooth serosa were collected retrospectively.Three radiologists read all images regarding morphological features,while the CT value and enhancement value of regions of interest (ROIs)located in the outer of lesion were calculated.Cut-off analysis was performed to determine optimal threshold levels of enhancement value to discriminate T4a and T3 gastric cancer.Di-agnostic performance of enhancement value and combination of enhancement value and morphologic assessment were compared with morphologic assessment by means of receiver operating characteristic (ROC)curve analysis.Results The sensitivity and specificity of morphological features was 66.67% and 33.33% respectively;the area under the ROC of enhancement value (between venous phase and plain scan)for differentiating T4a from T3 gastric cancer was 0.82,with a cut-off at 43.6 HU,sensitivity of 74.07% and specificity of 70.83%.Combined conventional standard and enhancement value,sensitivity of 100.00% and specificity 26.31%. Conclusion For differentiation of T4a and T3 gastric cancer by means of MDCT,enhancement value is found to be superior to con-ventional standard.