Semi-quantitative Analysis Of Hepatic And Pancreatic Fat Based On Dixon Method Of Magnetic Resonance Imaging And Their Clinical Significances

Part one:Semi-quantitative Analysis of Hepatic Fat Based on Dixon Method of Magnetic Resonance Imaging and Its Clinical SignificanceObjective:To measure the hepatic fat fraction(HFF)and investigate the correlation between HFF and other clinical outcome indicators,then summarize its clinical significance.Methods:The hepatic fat fractions(HFF)were measured after Dixon scans of magnetic resonance imaging with 95 adults,according to which this cohort was divided into high fat group and low fat group.Total abdominal fat area(TA),visceral fat area(VA)and subcutaneous fat area(SA)were measured.We tested the fasting blood glucose(FPG),total cholesterol(TC),triglyceride(TG),low density cholesterol(LDL-c),high density cholesterol(HDL-c)and blood pressure of the participants,body mass index(BMI)was then calculated.The percentage of Metabolic Syndrome(MS)was calculated for different groups of hepatic fat content.Results:The levels of FPC,TG,LDL-c,systolic blood pressure,diastolic blood pressure,VA,TA and visceral fat percentage(VFP)in high HFF group were significantly higher than those in low HFF group(P<0.05),while the abdominal subcutaneous fat percentage was significantly lower(P<0.05).HFF was positively correlated with FPG,TG,LDL-c,VA,TA,VFP,age and BMI(r = 0.354,0.370,0.415,0.299,0.285,0.238,0.203,0.221,respectively;P<0.05).With the increasing of liver fat,the rate of metabolic syndrome also gradually increased.Conclusion:There were positive correlations between between liver fat content and FPC,TG,LDL-c,VA,TA,VFP,age,and BMI.The results of this study could provide a reliable basis for clinical diagnosis and treatment of nonalcoholic fatty liver disease(NAFLD).Part two:Measurement of Pancreatic Fat Fraction Based on Dixon Method of Magnetic Resonance Imaging and Its Related Factors Objective:To analyze the pancreatic fat fraction based on magnetic resonance Dixon sequence and its related factors.Methods:The magnetic resonance imaging Dixon technique was used to determine pancreas fat fraction(PFF)of 95 adults.The cohort was divided into fatty pancreas group(PFF>8.9%)and normal pancreas group(PFF<8.9%)according to its median PFF.Total abdominal fat area(TA),visceral fat area(VA)and subcutaneous fat area(SA)were measured by Image J software,subcutaneous fat percentage(SFP)and Visceral fat percentage(VFP)were also calculated.Fasting blood glucose(FPG),total cholesterol(TC),triglyceride(TG),low density cholesterol(LDL-c),high density cholesterol(HDL-c)of this cohort were determined,blood pressure and body-mass index(BMI)were also collected.The differences in fat area,SFP,VFP,blood pressure and clinical biochemical indexes were analyzed between the two groups,and Pearson correlation analysis was used to verify the correlation between PFF and these parameters.The percentage of Metabolic Syndrome(MS)was calculated for different groups of pancreatic fat content.Multivariate logistic regression was used to analyze the risk factors of pancreatic fat infiltration.Results:The levels of BMI,FPC,TG,LDL-c,systolic blood pressure,VA,TA and VFP of fatty pancreas group were significantly higher than those of normal group(P<0.05).PFF was positively correlated with FPG,TG,LDL-c,VA,TA,VFP,systolic blood pressure,diastolic blood pressure,BMI and age(r=0.323,0.343,0.269,0.515,0.480,0.434,0.430,0.222,0.481,0.344;P<0.05).SFP was negatively correlated with PFF.With the increasing of pancreatic fat,the rate of metabolic syndrome also gradually increased.VA(P = 0.001,95%CI:0.015-0.049)and age(P = 0.005,95%CI:0.010-0.175)were independent risk factors for pancreatic fat content.Conclusion:PFF have a certain correlation with age,BMI,blood pressure,abdominal fat area and blood lipid metabolism.PFF measurement based on Dixon magnetic resonance imaging can provide accurate quantitative indicators for the study of non-alcoholic fatty pancreatic disease(NAFPD).Part three:A Comparative Study of Fat Content in Liver and Pancreas Assessed by Dixon Magnetic Resonance Imaging MethodObjective:To compare pancreatic fat content and hepatic fat content between hyperglycemia group and normoglycemia group using the Dixon method,and explore their correlations with hepatic fat content.Methods:The hepatic fat fractions(HFF)and pancreas fat fraction(PFF)were measured after Dixon scans of magnetic resonance imaging with 95 adults.All participants were divided into hyperglycemia group and normoglycemia group.We compared the HFF and liver PFF in these two groups,the correlation between liver and pancreatic fat content was analyzed.Results:The average fat content of the liver in hyperglycemia group was higher than that in normoglycemia group.Hepatic and pancreatic fat fraction were 8.3±6.9%and 5.5%±3.2%(t=-2.209,P<0.05),as well as 13.05±8.48%and 9.24±6.12%(t=-1.829,P>0.05),respectively,in the two groups.Correlation coefficients in the two samples of liver and pancreatic fat content were 0.404(P<0.05)and 0.328(P<0.05),both of them were correlated each other.Conclusions:Hepatic content in hyperglycemia people were higher than that of normoglycemia people,and the pancreatic and hepatic fat content were both positively correlated with each other in the two groups.