Feasibility Of Functional MRI Techniques In Distinguishing Different Depth Of Myometrial Invasion Of Endometrial Carcinoma In Stage Ⅰ

Objective:To offer new ideas for preoperative staging of endometrial carcinoma and guide clinical treatment,we investigated the feasibility of functional MRI techniques,including DWI（diffusion weighted imaging）,DKI（diffusion kurtosis imaging）,IVIM（introvoxel incoherent motion imaging）and ESWAN（enhanced T₂*weighted angiography）techniques,in distinguishing different depth of myometrial invasion of endometrial carcinoma in stage I.Materials and Methods:The clinical and medical imaging data of forty eight pathologically proved endometrial carcinoma patients including 25 in stage IA and 23 in stage IBwere enrolled in this study.All patients underwent pelvic MRI scanning on 1.5T scanner from February 2016 to January 2019,including the routine T₁WI,T₂WI,dynamic contrast enhancement,DWI（b=0,600 s/mm²）and ESWAN sequences.Among those patients,15 in stage IA and 11 in stage IB underwent DKI（b=0,1000,2000s/mm²）and IVIM（b=0,20,50,100,150,200,400,800,1200,2000,3000 s/mm²）scanning.Two radiologists reviewed MR images and measured quantitative parameters using the Functool on GE ADW4.6 workstation.The apparent diffusion coefficient（ADC）value and R₂*value were derived from DWI and ESWAN sequence,respectively.The fractional anisotropy（FA）,mean diffusivity（MD）,axial diffusivity（Da）,radial diffusivity（Dr）,fractional anisotropy of kurtosis（FAk）,mean kurtosis（MK）,axial kurtosis（Ka）andradial kurtosis（Kr）value were derived from DKI.The distributed diffusion coefficient（DDC）and the heterogeneity of intravoxel diffusion（α）value were derived from IVIM.The consistency of measurements taken by two radiologists was established using intraclass correlation coefficients（ICC）.These parameters were statistically compared between IA and IB groups.ROC analysis was performed to evaluate the diagnostic performance and to discover the corresponding threshold.Results:The inter-observer reliability were verified（ICC≥0.75）.The ADC values showed no significant difference between IA and IB groups.The MD,Da and Dr values of stage IB group were significantly lower than that of stage IA group[（0.940±0.138）um²/ms vs.（1.089±0.111）um²/ms,P=0.006;（1.167±0.196）um²/ms vs.（1.349±0.121）um²/ms,P=0.007;（0.860±0.127）um²/ms vs.（0.960±0.112）um²/ms,P=0.045],while the MK,Ka and Kr values were significantly higher[（1.019±0.104）vs.（0.879±0.058）,P<0.001;（1.154±0.160）vs.（1.004±0.090）,P=0.006;（0.888±0.087）vs.（0.737±0.076）,P<0.001].The FA and FAk values were not found to exhibit significant difference between two groups.MK’s and Kr’s areas under the ROC curve（AUC）were0.897 and 0.909,respectively.The best cutoff value of MK were 0.916 with sensitivity of 86.7%,specificity of 90.9%,PPV of 92.9%,NPV of 83.3%and accuracy of 88.5%,when the best cutoff value of Kr were 0.861 with sensitivity of 100%,specificity of72.7%,PPV of 83.3%,NPV of 100%and accuracy of 88.5%.Theαvalue of stage IB was significantly higher than that of stage IA group[（0.717±0.060）vs.（0.665±0.056）,P=0.032],while the DDC value showed no significant difference between two groups.The ACU ofαvalue was 0.776 with sensitivity of 66.7%,specificity of 90.9%,PPV of90.9%,NVP of 66.7%and accuracy of 76.9%,when the critical value was 0.666.The R₂*value of stage IB was significantly higher than that of stage IA group[（15.77±2.45）Hz vs.（11.73±2.71）Hz,P<0.001].The AUC of R₂*was 0.889,and the best cutoff was 13.160Hz with sensitivity of 76.0%,specificity of 95.7%,PPV of95.0%,NPV of 78.6%and accuracy of 85.4%.Conclusion:The functional MRI techniques demonstrate good application value in staging endometrial carcinoma in stage I.The MK and Kr value derived from DKI sequence and the R₂*value derived from ESWAN sequence show high diagnostic efficiency.