Study Of Functional Magnetic Resonance Imaging In Bladder Cancer

Part Ⅰ Intravoxel incoherent motion MRI for prediction of histological grade and muscle invasion in bladder urothelial carcinoma[Objective]To evaluate the utility value of MR intravoxel incoherent motion(IVIM)in histological grade and muscle invasion of bladder urothelial carcinoma.[Materials and Methods]According to postoperative histologic grade and T staging,60 patients with bladder urothelial carcinoma confirmed by surgery and pathology were divided into low grade(LG)and high grade(HG)group,non-muscle invasive bladder cancer(NMIBC)or muscle invasive bladder cancer(MIBC)group.MR IVIM parameters(apparent diffusion coefficient standard[ADCst],true diffusion coefficient[D],pseudo-diffusion coefficient[D*]and perfusion fraction[f])between groups were compared with independent-samples t test.A binary logistic regression model was established to evaluate the predicted probability of combined IVIM parameters.The ROC curves of IVIM parameters and their combination’s predicted probability were drawn and the diagnostic efficiency were evaluated.[Results]ADCst,D and f values of HG group were significantly lower than those of LG group(P<0.05).Area under ROC curve(AUCs)for ADCst,D and f values to differentiate HG from LG were 0.88,0.86 and 0.72,respectively,and AUCs for predicted probability of combined ADCst and D,combined ADCst and f and combined D and f were 0.91,0.90 and 0.88,respectively.ADCst,D and f values of MIBC group were significantly lower than those of NMIBC(P<0.0001).AUCs for ADCst,D and f value to differentiate MIBC from NMIBC were 0.91,0.85 and 0.88,respectively,and all the AUCs for predicted probability of combined ADCst and D,combined ADCst and f and combined D and f were 0.93.[Conclusions]Lower ADCst,D and f values may indicate greater possibility of high grade and muscle invasion of bladder urothelial carcinoma.Combination of IVIM parameters can improve diagnostic efficacy.Part Ⅱ Quantitative assessment of early response to neoadjuvant chemotherapy for bladder cancer:comparison of three methods of region of interest positioning for ADC measurements[Objective]To evaluate the utility of apparent diffusion coefficient(ADC)in assessment of early response to neoadjuvant chemotherapy(NAC)in bladder cancers and compare the impact of three different methods of region of interest(ROI)positioning for ADC measurements.[Materials and Methods]Twenty-four patients were inspected through DWI MR scanning before NAC and after two circles of NAC from March 2016 to January 2018,All cases were categorized into response group(14 cases)or non-response group(10 cases)according to RECIST 1.1.Pre-and post-NAC ADC values(pre-and post-ADC)were measured by using single-section(SS),three circular ROIs(three-ROIs)and whole-tumor volume(WTV)measurement methods respectively and then numeric and percentage values of ADC changes(△ADC and%△ ADC)were calculated.Pre-ADC and post-ADC values were compared by paired-sample t test.Comparisons of pre-ADC,post-ADC,△ADC and%△ADC values between response and non-response groups were performed by using independent sample t test.Diagnostic performance was calculated by means of receiver operating characteristics(ROC)analysis.[Results]Post-ADC values derived from three ROI methods were significantly higher than pre-ADC values respectively(P<0.05).Post-ADC values derived from three ROI positioning methods and △ADC values derived from three-ROIs and SS positioning methods in response group were significantly higher than those in non-response group respectively(P<0.05),but pre-ADC values derived from all the three ROI positioning methods did not show significant differences between response and non-response groups.Post-ADC value derived from WTV and SS positioning methods yielded high areas under ROC curves(AUCs)of 0.91 and 0.90 respectively.Post-ADC and △ADC values derived from three-ROIs positioning method and △ADC value derived from SS positioning method showed AUCs of 0.81,0.80 and 0.79 respectively.[Conclusion]Post-ADC and △ADC values can work as biomarkers to distinguish responders from non-responders after early NAC in bladder cancers.ADC value measurement was highly dependent on the ROI positioning method,and WTV and SS measurement methods yield greater accuracy than three-ROIs measurement method in early response assessment.