The Diagnostic Value Of Multimodal MR Imaging For Differentiating The Histological Types And Lymph Vascular Space Invasion Of Endometrial Carcinoma

Objective:The aim of this study was to investigate the value of multimodal MR,including dynamic contrast enhanced MRI?DCE-MRI?,diffusion weighted imaging ?DWI?,intravoxel incoherent motion imaging?IVIM?,diffusion kurtosis imaging?DKI?and enhanced T₂^* weighted angiography?ESWAN?techniques,for differentiating histological types and lymph vascular space invasion?LVSI?of endometrial carcinoma.Materials and Methods:Sixty eight patients with histopathological proven endometrial carcinoma were retrospectively enrolled between February 2015 and August 2019.According to the histological types,they were divided into type I group?n=35?,and type II group?n=33?.According to the histopathology with or without LVSI,they were divided into LVSI positive group?n=17?,and LVSI negative group?n=51?.All patients underwent conventional pelvic MRI before hysterectomy,including routine T₁WI,T₂WI,DWI?b=0,600 s/mm²?,DKI?b=0,1000,2000 s/mm²?and ESWAN sequences.Among these patients,62 patients underwent DCE-MRI?40 phases in 250seconds?and IVIM?b=0,20,50,100,150,200,400,800,1200,2000,3000 s/mm²?scanning.On the GE ADW 4.6 workstation,the Gen IQ post-processing software was used to post-process the DCE-MRI sequence images,the Functool post-processing software was used to post-process the DWI,IVIM,DKI and ESWAN sequence images.The transfer rate constant(K^trans),intravasation rate constant(K_ep),fraction volume of extravascular extracellular space?V_e?value were derived from DCE-MRI.The apparent diffusion coefficient?ADC?value was derived from DWI.The slow apparent diffusion coefficient?ADC-slow?,fast apparent diffusion coefficient?ADC-fast?,perfusion fraction?f?,distributed diffusion coefficient?DDC?and the heterogeneity of intravoxel diffusion???value were derived from IVIM.The mean kurtosis?MK?,axial kurtosis?Ka?,radial kurtosis?Kr?,mean diffusivity?MD?,axial diffusivity?Da?,radial diffusivity?Dr?,fractional anisotropy?FA?and fractional anisotropy of kurtosis?FAk?value were derived from DKI.The R₂^* value was derived from ESWAN sequence.Intra-class correlation coefficients?ICC?was used to evaluated the consistency of the two radiologists.The differences of these parameters were analyzed using independent-sample t test and Mann-Whitney U-test depend on the data distribution.The diagnostic efficacy of parameters were analyzed by receiver operating characteristic?ROC?curve.Results:The consistency of each measured quantitative parameter from two radiologists was good?ICC?0.75?.The K^transvalue of type I group was lower than type II group[?0.337±0.058?min^-1vs.?0.501±0.087?min^-1,P<0.001].The AUC of K^transwas0.956,and the best cutoff was 0.389 min^-1with sensitivity of 96.6%,specificity of87.9%,PPV of 87.5%,NPV of 96.7%and accuracy of 91.9%,while the K_epand V_evalue showed no significant difference between the two groups.The K^trans,K_epand V_evalues showed no significant difference between LVSI positive and LVSI negative groups.The ADC value of type I group was higher than type II group[?0.965±0.099?×10^-3mm²/s vs.?0.878±0.134?×10^-3mm²/s,P=0.003].The AUC of ADC was 0.713,and the best cutoff was 0.934×10^-3mm²/s with sensitivity of 72.7%,specificity of 62.9%,PPV of 64.9%,NPV of 71.0%and accuracy of 67.6%.The ADC value in LVSI positive group was lower than LVSI negative group[?0.839±0.114?×10^-3mm²/s vs.?0.948±0.110?×10^-3mm²/s,P=0.001].The AUC of ADC was 0.764,and the best cutoff was 0.837×10^-3mm²/s with sensitivity of 52.9%,specificity of 90.2%,PPV of 64.3%,NPV of 85.2%and accuracy of 80.9%.The ADC-slow and DDC values of type I group were higher than type II group[?0.534±0.039?×10^-3mm²/s vs.?0.404±0.051?×10^-3mm²/s,P<0.001;?1.034±0.182?×10^-3mm²/s vs.?0.807±0.218?×10^-3mm²/s,P<0.001].The AUC of ADC-slow was 0.978,and the best cutoff was 0.467×10^-3mm²/s with sensitivity of 93.1%,specificity of 97.0%,PPV of 96.4%,NPV of 94.1%and accuracy of 95.2%.The AUC of DDC was 0.783 with sensitivity of 65.5%,specificity of 84.8%,PPV of 79.2%,NPV of 73.7%and accuracy of 75.8%,when the best cutoff was 0.890×10^-3mm²/s.The ADC-fast?f and?values revealed no significant difference between the two groups.The ADC-slow?ADC-fast?f?DDC and?values showed no significant difference between LVSI positive and LVSI negative groups.The MK,Ka and Kr values of type I group were lower than type II group[?0.849±0.113?vs.?0.994±0.134?,P<0.001;?0.935±0.172?vs.?1.125±0.219?,P<0.001;?0.736±0.105?vs.?0.869±0.148?,P<0.001],while the MD,Da and Dr values of type I were higher[?1.225±0.270?um²/ms vs.?0.996±0.220?um²/ms,P<0.001;?1.496±0.319?um²/ms vs.?1.207±0.247?um²/ms,P<0.001;?1.090±0.254?um²/ms vs.?0.890±0.219?um²/ms,P=0.001].The FA and FAk values demonstrated no significant difference between the two groups.The AUC of MK was 0.798,and the best cutoff was 0.853 with sensitivity of 87.9%,specificity of 60.0%,PPV of 67.4%,NPV of84.0%and accuracy of 73.5%.The AUC of Kr was 0.805 with sensitivity of 81.8%,specificity of 74.3%,PPV of 75.0%,NPV of 81.3%and accuracy of 77.9%,when the best cutoff was 0.787.The MK,Ka and Kr values in LVSI positive group were higher than LVSI negative group[?1.028±0.107?vs.?0.886±0.136?,P<0.001;?1.153±0.205?vs.?0.979±0.191?,P=0.002;?0.888±0.111?vs.?0.768±0.144?,P=0.003],while the MD,Da and Dr values in LVSI positive group were lower[?0.970±0.187?um²/ms vs.?1.157±0.261?um²/ms,P=0.008;?1.186±0.195?um²/ms vs.?1.410±0.318?um²/ms,P=0.001;?0.862±0.197?um²/ms vs.?1.031±0.244?um²/ms,P=0.012].The FA and FAk values were not significantly different between the two groups.The AUC of MK and Kr were 0.799 and 0.753,respectively.The best cutoff value of MK was 0.928 with sensitivity of 82.4%,specificity of 66.7%,PPV of 45.2%,NPV of 91.9%and accuracy of 70.6%,and the best cutoff value of Kr was 0.824 with sensitivity of 76.5%,specificity of 66.7%,PPV of 43.3%,NPV of 89.5%and accuracy of 69.1%.The R₂^*value of type I was significantly lower than type II group[?12.35±1.55?Hz vs.?16.16±2.41?Hz,P<0.001].The AUC of R₂^*was 0.907,and the best cutoff was 14.07Hz with sensitivity of 75.8%,specificity of 94.3%,PPV of 92.6%,NPV of 80.5%and accuracy of 85.3%.The R₂^*value in LVSI positive group was significantly higher than LVSI negative group[?16.27±2.08?Hz vs.?13.50±2.16?Hz,P<0.001].The AUC of R₂^*was 0.835,and the best cutoff was 14.75 Hz with sensitivity of 82.4%,specificity of80.4%,PPV of 58.3%,NPV of 93.2%and accuracy of 80.9%.Conclusions:The multimodal MR imaging parameters can effectively evaluate the type I and type II of endometrial carcinoma,the K^transvalue derived from DCE-MRI,the ADC-slow value derived from IVIM and the R₂^*value derived from ESWAN sequence have high diagnostic efficiency;for with or without lymph vascular space invasion of endometrial carcinoma,the R₂^*value derived from ESWAN sequence has high diagnostic efficiency.