The Value Of ESWAN In Evaluating Aggressiveness Of Epithelial Ovarian Cancers

Objective:The aim of this study is to investigate the potential of enhanced T₂ star weighted angiography（ESWAN）in evaluating the aggressiveness of epithelial ovarian cancers（EOCs）,which can provide detailed information for clinical treatment.Materials and Methods:Thirty-four patients with 37 histopathology proven EOCs（14 BEOTs,23 MEOTs）were retrospectively analyzed.MRI scan including ESWAN sequence was performed on a 1.5T scanner（GE Signa HDXT）.The ESWAN images were transferred to a GE SDC-ADW 4.6 workstation for post-processing.The magnitude,phase,R₂*and T₂*maps were reconstructed automatically,and two experienced radiologists blindly reviewed and analyzed the data.The manual regions of interest（ROIs）were drawn along the boundaries of tumors on the slice with maximal solid area,according to fat suppression T₂WI and LAVA.A P value less than0.05 was considered as statistically significant.The intra-observer consistency of thrice measurements by two observers respectively was tested by intra-class correlation coefficients（ICC）using SPSS 22.0 statistical software and the inter-observer consistency of average values by two observers was analysed by Bland-Altman test using MedCalc 15.2.2 statistical software.The data with better intra-observer agreement were used for the statistical analysis.The magnitude,phase,R₂*and T₂*values of BEOTs and MEOTs were compared in independent-sample t test.The receiver operating characteristic（ROC）curve was used to evaluate the diagnostic efficiency.The correlation between the grade of intertumoral susceptibility signal（ITSS）and invasiveness of EOCs was tested by Spearman correlation test.Results:Both intra-class and inter-class consistency by two observers were all good.The values of magnitude and phase between BEOTs and MEOTs didn’t show significant difference（P>0.05）,while the values of R₂*and T₂*between BEOTs and MEOTs showed significant difference.The R₂*value of BEOTs was statistically lower than that of MEOTs（[5.98±1.79 vs.11.40±3.66]Hz,P<0.001）,whereas the mean T₂*value of BEOTs was statistically higher than that of MEOTs（[187.91±75.57 vs.129.09±28.48]ms,P=0.01）.The area under the curve（AUC）of R₂*values was 0.894（95%confidence interval,CI:0.749-0.971）and the corresponding cutoff value was 7.50 Hz,with a sensitivity,specificity and accuracy of85.7%,82.6%and 86.5%respectively,and with a positive predictive value（PPV）and negative predictive value（NPV）of 89.0%and 77.8%respectively.The AUC of T₂*values was 0.776（95%CI:0.610-0.896）and the corresponding cutoff value was143.73 ms with a sensitivity,specificity and accuracy of 71.4%,82.6%and 78.4%respectively,and with a PPV and NPV of 87.1%and 63.7%respectively.The AUC between R₂*and T₂*has no significant difference（P=0.21,95%CI:﹣0.067-0.303）.There was a statistically significant difference between ITSS grade and EOCs invasiveness（r_s=0.45,P=0.005）,and the ITSS grade was moderate and positivecorrelated with tumor invasivenessConclusion:The R₂*and T₂*values of MR-ESWAN can be used in evaluating the aggressiveness of EOCs.The R₂*showed higher sensitivity and accuracy than T₂*.The ITSS on ESWAN minIP image revealed positively correlated with the invasiveness of EOCs.ESWAN technique would be very promising in evaluating the aggressiveness of EOCs.