T₂WI Histogram Analysis In Categorization Of Ovarian Epithelial Cancer:Correlation With Ki-67 Expression

Objective:1.To evaluate the value of T₂WI histogram analysis in categorization of epithelial ovarian cancer.2.To evaluate whether the parameters derived from the histogram combined with the serum CA125 can improve the diagnostic efficiency.3.To investigate the correlation between histogram-derived parameters and ki-67 expression in ovarian cancer patients.Methods:Eighty-six pathologically proven ovarian epithelial cancer（OEC）patients were retrospectively analyzed.All included samples had complete MRI images,clinical data and pathological results.Clinical characteristics of the patients were queried through the Hospital Information System（HIS）,including the patients’ age,serum CA125 levels and ki-67 expression.The axial T₂WI fat suppression sequence images of all patients were imported into ITK-SNAP software to delineate the region of interest（ROI）and the corresponding histogram was obtained by Pyradiomics software.The following histogram parameters were recorded respectively: Mean,Variance,skewness,Kurtosis,the 10 th percentile and 90 th percentile.The Independent sample T-test and Mann-Whitney U test was used to evaluate the clinical characteristics and the histogram-derived parameters between the two types.The meaningful histogram-derived parameters were counted,and the corresponding receiver operating characteristic curve（ROC）was drawn to analyze the diagnostic efficiency of OEC classification and whether histogram-derived parameters combined with serum CA125 could further improve the diagnostic efficiency.The correlation between the histogram-derived parameters and ki-67 expression was evaluated by Pearson test.Results:1.The age,serum CA125 level and Ki-67 expression of type I group were lower than those of type II group in OEC patients,the differences were statistically significant（P < 0.05）.Based on the total tumor volume histogram parameters,Mean,Variance,Skewness and 90 th in the type I group were higher than those in the type II group,and the corresponding areas under ROC were 0.624,0.641,0.736 and 0.625,respectively.Skewness had the highest diagnostic efficiency for the classification.The sensitivity and specificity were 0.662 and 0.784 respectively.Based on the total tumor solid component volume histogram parameters,Variance,Kurtosis and 10 th of type I group were higher than those of type II group,and the corresponding areas under ROC were 0.688,0.636 and 0.669,respectively.Among them,Variance had the highest diagnostic efficiency,and the sensitivity and specificity were 0.324 and 0.973 respectively.2.Based on the parameters of the total tumor volume histogram,Skewness combined with serum CA125 can further improve the diagnostic efficacy.1/Variance combined with serum CA125 does not improve the diagnostic efficacy based on the total tumor solid component volume histogram parameters.3.There was no correlation between ki-67 expression and the derived parameters based on T₂WI total tumor volume histogram or total solid component volume histogram.Conclusion:1.The parameters derived from T₂WI histogram are helpful in categorization OEC.2.The parameters derived from T₂WI combined with the serum CA125 level are helpful in categorizing OEC.3.The parameters derived from T₂WI could not predict the Ki-67 expression status.