Application Of IVIM-DWI And 3D PcASL In The Staging And Prediction Of Early Effect Of Nasopharyngeal Carcinoma

Part1 To explore the application of IVIM-DWI and 3DPCASL in the staging of nasopharyngeal carcinomaObjective:To explore the relationship between intravoxel incoherent motion diffusion-weighted imaging（IVIM-DWI）and three-dimensional pseudo continuous arterial spin labeling（3D p CASL）in different stages of nasopharyngeal carcinoma（NPC）.Materials and methods:One hundred patients with newly diagnosed,histologically proven NPC were initially recruited in this study from October2019 to October 2020 and underwent all routine MRI,3D pseudo-continuous ASL and IVIM-DWI examinations.According to AJCC 8th edition staging system,the patients were divided into total clinical staging,TN staging,high and low staging.Measurement of IVIM-DWI related parameters,including pure molecular diffusion（D）,perfusion-related diffusion coefficient（D*）and perfusion fraction（f）,and values of Maximum blood flow(BF_max)derived from 3D p CASL to analyze the correlation among NPC stages and compare the difference between the high and low-grade groups.Results:T staging showed negative correlation with D（r=-0.25,p<0.05）,N staging showed negative correlation with D value（r=0.31,p<0.05）.The total clinical staging showed negative correlation with D and f（r=0.41,-0.19,p<0.05）.The values of D,D*and f were higher in the low-grade group than in the high-grade group.In T staging,D=0.79±0.19(×10^-3mm²/s)for low grade group vs.0.71±0.12(×10^-3mm²/s)for high-grade group（p=0.010）.In N staging,the D=0.82±0.19(×10^-3mm²/s)for low-grade groupvs.0.68±0.09(×10^-3mm²/s)for high-grade group（p<0.001）,and D*=14.25±5.09(×10^-3mm²/s)for low-grade group vs.12.00±4.86((×10^-3mm²/s)for high-grade group（p=0.028）.In the total clinical staging,the D=0.87±0.22(×10^-3mm²/s)for low-grade group vs.0.70±0.10(×10^-3mm²/s)for high-grade group（p<0.001）.The f value in low-grade group was higher than in high-grade group（0.32±0.09 vs.0.28±0.08）（p=0.035）,but the BF_max=113.17±51.99（m L/min/100 g）for low-grade group vs.（146.65±77.14）（m L/min/100 g）for high-grade group.The BF_maxvalue was negatively correlated with D*（r=-0.052,P>0.05）,but positively correlated with f value（r=0.043,P>0.05）.The diagnostic efficiency of D value in T,N and clinical staging of nasopharyngeal carcinoma was low,but it was higher than other parameters,and the ROC area was about 0.621,0.642 and 0.683,respectively.Conclusion:IVIM-DWI and 3D p CASL can noninvasively reflect the information of the diffusion and blood perfusion of nasopharyngeal carcinoma,and play a certain guiding role in the staging of nasopharyngeal carcinoma.Part2 Application of voxel incoherent motion imaging and arterial spin labeling in the prediction of early response of nasopharyngeal carcinomaPurpose: To investigate the value of intravoxel incoherent motion diffusion-weighted imaging（IVIM-DWI）and three-dimensional pseudo-continuous arterial spin labeling（3D p CASL）in predicting the early response to chemoradiotherapy（CRT）in nasopharyngeal carcinoma（NPC）.Materials and methods: Fourty patients with newly diagnosed NPC underwent pre-treatment IVIM-DWI and（3D p CASL）were divided into complete remission group（CR）and incomplete remission（n CR）after CRT.The differences of IVIM-DWI related parameters including pure diffusion coefficient（D）,pseudo-diffusion coefficient（D*）,perfusion fraction（f）,and 3D p CASL related parameters average blood flow（BFavg）,minimum blood flow（BFmin）,and maximum blood flow（BFmax）between the two groups were analyzed by independent sample t-test.The diagnostic performance of each parameter to the curative effect was analyzed by ROC curve.Results: D = 0.71 ±0.12（× 10-3mm2/s）in the CR group was lower than that in the n CR group 0.85 ±0.22（× 10-3mm2/s）,and the difference was statistically significant（P=0.014）.There was no statistical significance in D* and f（p=0.899,0.568）.BFavg=85.05 ±23.11g（m L/min/100 g）in CR group was higher than 62.25 ±23.57g（m L/min/100 g）in n CR group.The BFmax=136.86 ±52.407（m L/min/100g）for CR group was higher than in the n CR group（m L/min/100 g）,and the difference was statistically significant（p < 0.05）,but the parameter BFmin was not statistically significant（p=0.54）.The area under the ROC curve of D,BFavg,and BFmax for predicting the curative effect of nasopharyngeal carcinoma was 0.731,0.753,and 0.724 respectively.The area under the ROC curve of the combination of BFavg and BFmax for predicting the curative effect of nasopharyngeal carcinoma was0.812.Conclusion: IVIM-DWI’s diffusion value and 3Dp CASL related blood flow parameters are helpful to predict and evaluate the early curative effect of nasopharyngeal carcinoma after radiotherapy and chemotherapy.