IVIM-DWI Application And Research Of The Differential Diagnosis Of Pancreatic Cancer And Chronic Pancreatitis

Objective:In this study,the intravoxel incoherent motion(IVIM)magnetic resonance diffusion weighted imaging(DWI)double exponential model with multiple b values was used to compare the routine ADC value of DWI and the pure diffusion coefficient(D),pseudo-diffusion coefficient(D*)and perfusion fraction(f)from IVIM-DWI of pancreatic cancer,chronic pancreatitis and cancerous relative normal pancreatic tissue;to study the optimal diagnostic threshold and diagnostic performance of the above parameters in the differential diagnosis of pancreatic cancer,chronic pancreatitis and cancerous relative normal pancreatic tissue.Methods:Select from December 2015 to January 2017 in our hospital by pathology biopsy confirmed and in line with clinical diagnosis?the follow-up 1-6 months confirmed that pancreatic cancer and chronic pancreatitis in 55 patients,and divide into pancreatic cancer group?the chronic pancreatitis group,the cancerous relative normal pancreatic tissue was selected as the control group.All MRI examinations were performed on a Philips Achieva 3.0T TX magnetic resonance scanner.The scan sequence includes T2WI,T1WI,Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)and conventional transverse axis DWI(b values of 0 and 700s/mm2).IVIM(b values of 0,20,40,70,100,200,400,700,1000s/mm2)were scanned for all cases.The conventional ADC images were obtained by fitting the conventional DWI with b-value 0 and 700s/mm2 by using Philips's own post-processing workstation,and the Region of interest(ROI)was placed to calculate the ADC value of the lesion and the cancerous relative normal pancreatic tissue,and the D,D*and f values of the lesion and the cancerous relative normal pancreatic tissue were calculated by using Philips developed software(IVIM v1.0,For Philips Data Only)to process the IVIM-DWI image and placing the ROI,and the corresponding parameter pseudo color map was generated automatically by the software.The differences of ADC value,D value,D*value and f value between pancreatic cancer group,chronic pancreatitis group and cancerous relative normal pancreas tissue group were analyzed by one-way ANOVA and t-test with the results.using receiver operating characteristic(ROC)curve to calculate the area under curve(AUC),to analysis the sensitivity?specificity and diagnostic value of the four parameters of ADC value,D value,D*value and f value to distinguish between pancreatic cancer,chronic pancreatitis and cancerous relative normal pancreatic tissue.Result:1.In this study,35 cases of pancreatic cancer,23 cases of surgical pathology confirmed,12 cases by following-up from one to six months to the presence of pancreatic metastases as the criteria to confirm;20 cases of chronic pancreatitis,surgical pathology confirmed 11 cases,9 cases by following-up 1-6 months to Confirm.2.The results of single factor analysis of variance showed that the D value in pancreatic cancer group,chronic pancreatitis group and normal pancreatic tissue group was not statistically significant(F=0.045,p=0.956),ADC value(P=3.937,p=0.022),D*value(F=97.125,p<0.001)and f value(F=118.917,p<0.001)in pancreatic cancer group,chronic pancreatitis group and normal pancreatic tissue group were statistically significant.A further one and one group comparison,D values were not statistically significant between groups of pancreatic cancer group,chronic pancreatitis group and normal pancreatic tissues(1.29± 0.27vs1.31±0.21×10-3mm2/s,p=0.776;1.29±0.27vs1.30±0.21×10-3mm2/s,p=0.955;1.31 ±0.21vs1.30±0.21 X 10-3mm2/s,p=0.796);ADC values except for pancreatic cancer group and its own normal pancreatic tissue group were no significant difference between the other two groups(1.31±0.29vs1.53±0.44 X 10-3mm2/s,p =0.008;1.31±0.29vs1.38±0.33×10-3mm2/s,p=0.494;1.38±0.33vsl.53±0.44 ×10-3mm2/s,p = 0.132).The D*values except for the pancreatic cancer group and pancreatitis group were were statistically significant between the other two groups(21.34 ± 9.34 vs 24.97 ± 8.09 X 10-3mm2/s,p = 0.324;21.34 ±9.34vs57.38 ± 16.19×10-3mm2/s,p<0.001;24.97±8.09vs57.38±16.19×10-3mm2/s,p<0.001);f value were significant difference between the pancreatic cancer group,the chronic pancreatitis group and the normal pancreatic tissue group(0.26±0.054 vs 0.36±0.022,p<0.001;0.26±0.054 vs 0.40±0.037,p<0.001;0.36±0.022vs0.40±0.037,p<0.001).3.Pancreatic cancer group,chronic pancreatitis group and relative normal pancreas tissue group D value and ADC values were different,statistically significant(t=-2.784,p<0.05;t =-13.095,p<0.001;t =-3.386,p<0.05),ADC values were greater than D values.4.Area under curve of ADC.D*?f value of the distinction between pancreatic cancer and normal pancreatic tissue were 0.705?0.996 and 0.999,f value is the best diagnostic results,Optimal critical value of the three were 1.29×10-3mm2/s?37.33×10-3mm2/s?0.34,The sensitivity of the corresponding diagnosis are 81.8%?96.4%and 98.2%,and the specificity are 71.4%?94.3%and 97.1%,the area under curve of the D value was no statistical significance.Area under curve of f value of the differential diagnosis of pancreatic cancer and chronic pancreatitis was the largest area of 0.976,the optimal critical value was 0.32,The sensitivity and specificity of the corresponding diagnosis were 95%and 87.1%,area under curve of ADC?D?D*value are low and diagnostic worth is low.Area under curve of D*and f values the differential diagnosis of chronic pancreatitis and normal pancreatic tissue were 0.985 and 0.866,and the optimal critical value were 36.2×10-3mm2/s and 0.38,the sensitivity of the corresponding diagnosis are 94.5%?78.2%,the specificity were 90.0%?80.0%,ADC and D value of the area under curve are not statistically significant.Conclusion:1.ADC?D*?f value of pancreatic cancer,chronic pancreatitis and the cancerous relative normal pancreatic tissue are difference,suggesting that they contribute to the diagnosis of pancreatic cancer,chronic pancreatitis and the cancerous relative normal pancreatic tissue.2.Pancreatic cancer,chronic pancreatitis and the cancerous relative normal pancreatic tissue ADC values are greater than the D value,suggesting that conventional ADC values contain perfusion characteristics.3.D*?f value to identify pancreatic cancer and the cancerous relative normal pancreatic tissue is better,the optimal critical value are 37.33×10-3mm2/s,0.34(AUC=0.996?0.999,p<0.001),Sensitivity and specificity respectively are 100%?100%and 97.1%?97.1%.The differential diagnosis of f value of pancreatic cancer and chronic pancreatitis is the best,and the optimal critical value is 0.33,sensitivity and specificity are 95%?94.3%.D*?f value to identify chronic pancreatitis and the cancerous relative normal pancreatic tissue are better,the optimal critical value respectively are 38.9×10-3mm2/s?0.36,Sensitivity and specificity respectively are 96.4%?89.1%and 95%?70%.diagnostic efficiency of D*?f value to identify pancreatic cancer,chronic pancreatitis and the cancerous relative normal pancreatic tissue are better than conventional ADC value.