Utility Of Different Apparent Diffusion Coefficients For Preoperative Assessment Of Low Risk Endometrial Carcinoma

PurposeTo investigate the clinical value of meanADC、minADC and rADC values in predicting patients with low risk EC,and to identify an optimum ADC measurement for preoperative assessment.MethodsEighty-one patients with stage I EC who underwent DWI at 1.5T were included and divided into low group and high risk group based on the ESMO-ESGO-ESTRO classification.Clinical indexes,conventional MRI parameters,minimum ADC values（minADC）,mean ADC values（meanADC）and relative ADC values（rADC）were compared between those two groups.rADC was calculated using the equation ADC（cancer）/ADC（reference）with the obturator internus muscle as reference.The optimal ADC measurement and cut-off ADC value for low risk EC were calculated using the receiver operating characteristic（ROC）curve.ResultsThe low risk group had significantly higher meanADC,minADC,and rADC values than did the high risk group(1.095 vs.0.902×10^-3mm²/s,0.755 vs.0.657×10^-3mm²/s,0.754 vs.0.603,respectively).In assessments of low risk EC patients,the area under the curve（AUC）values for meanADC,minADC,and rADC were 0.840（95%CI,0.749,0.931）,0.681（95%CI:0.561,0.800）,and 0.876（95%CI:0.798,0.954）,respectively.The optimal cut-off rADC value for prediction was 0.669,the maximum Youden index,sensitivity,specificity,and accuracy values were 0.683,81.8%,86.5%,and 84.0%,respectively.ConclusionrADC is superior to minADC and meanADC for predicting patients with low risk EC,and could potentially stratify low risk EC patients from undergoing unnecessary lymphadenectomy and provide reliable imaging information for adequate surgical management.