The Research On Correlation Between The Adiabatic T1rho Values On 3.0T MRI And Tissue Composition Changes In Rat Hepatic Fibrosis Models

BackgroundOur previous research has found that MRT1rho sequence has high efficiency in the diagnosis of hepatic fibrosis in rat models.But it cannot reveal the influencing factors of T1rho values.The purpose of our study is to explore the correlation between adiabatic T1rho values and changed component information during the process of hepatic fibrosis by using analysis of laser Raman spectroscopy.Chapter ? Analysis of laser Raman spectrum results and clinical significance in hepatic fibrosis stage S0?S4 in rat modelsObjectiveTo collect Raman spectra of hepatic tissue,summarize characteristic peaks during hepatic fibrosis stage S0-S4 in rat models by using near infrared laser Raman spectroscopy,and analyse the value of near infrared laser Raman spectroscopy in early detection for different hepatic fibrosis stages and material composition changes in hepatic tissue.Materials and Methods65 healthy SD rats were randomly divided into blank group(15 rats)and experimental group(50 rats).Rats in blank control group were sampled drawn in turn for MRIT1rho scan,Raman spectroscopy detection and pathological examination.Rats in experimental group were subcutaneously injected with carbon tetrachloride oil of 50%solution of 0.2ml/100g,2 times a week.Two weeks after hepatic fibrosis models were made,3-5 model rats were randomly selected every week for MRIT1rho scan,Raman spectrum detection and pathological examination in turn.Results58 of the 65 rats were included in the final analysis,of them,SO 15,S1 11,S2 12,S3 10,and S4 10.Results showed Raman spectrum peaks in hepatic tissues staging for S0-S4 were stable and typical Raman spectra of hepatic tissue was respectively located at 848cm-1,1006cm-1,1268cm-1,1305cm-1,1442cm-1,1595cm-1,1658cm-1 band.They respectively belonged to tyrosine and collagen(848cm-1),phenylalanine respiratory chain beta carotene(1006cm-1),amide III lipid(1268cm-1),lipid(1305cm-1),lipid/phosphor lipid fatty acids,cholesterol(1442cm-1),quinones substances(1595cm-1)and collagen/elastin(1658cm-1).Peak intensity increased from stage SO to stage S4(P<0.05)at 1658cm-1 Raman spectrum band.Peak intensity decreased from stage SO to stage S4(P<0.05)at 1006cm-1 Roman spectrum band.Stage S2 group showed the highest peak intensity(P<0.05)at 1268cm-1,1305cm-11442cm-1 Raman spectrum band respectively.Stage SO group showed the highest intensity and stage S1 group showed the lowest intensity at 1595cm-1 Roman spectrum band.Conclusions(1)Raman spectrum peaks in hepatic tissue of the rats staging for S0-S4 are stable.There have characteristic peaks for quantitative analysis.(2)Near infrared laser Raman spectra can reflect substance composition changes during the process of hepatic fibrosis in rats and provide important clinical value for early detection and staging of hepatic fibrosis.Chapter ? The research on correlation between adiabatic T1rhovalues and composition changes in different hepatic fibrosis stages in rat modelsObjectiveTo analyse the correlation between 3.0 T magnetic resonance(MR)adiabatic T1rho values and hepatic component changes in different hepatic fibrosis stages in rat models,and to explore factors leading to changes of adiabatic T1rho values in the process of rat hepatic fibrosis.Materials and Methods65 healthy SD rats were randomly divided into blank group(15 rats)and experimental group(50 rats).Rats in blank control group were sampled drawn in turn for liver conventional MRI and T1rho check,Raman spectroscopy detection and pathological examination.Rats in experimental group were subcutaneously injected with carbon tetrachloride oil of 50%solution of 0.2 ml/100 g,2 times a week.Two weeks after hepatic fibrosis models were made,3-5 model rats were randomly selected every week for conventional MRIT1rho check,Raman spectrum detection and pathological examination in turn.Results58 of the 65 rats were included in the final analysis,of them,SO 15,S1 11,S2 12,S3 10,and S4 lO.The correspondent average adiabatic T1rho values from SO to S4 were 74.97±3.897ms,89.665±5.608ms,101.453±7.569ms,109.341±7.243ms and 115.922±7.094msrespectively.There were statistical differences among adiabatic T1rho values between any two groups.Adiabatic T1rho values were highly positive correlated with the stage of hepatic fibrosis(r=0.917,P<0.01).The components changed in the process of hepatic fibrosis measured by Raman spectra were tyrosine and collagen(848cm-1),phenylalanine respiratory chain beta carotene(1006cm-1),amide III lipid(1268cm-1),lipids(1305cm-1),lipid/phospholipid fatty acids and cholesterol(1442cm-1),quinones substances(1595cm-1)and collagen/elastin(1658cm-1).Among them,there was a certain correlation between the peak value of beta carotene and T1rho value(r=-0.342,P<0.01)and there was also a certain correlation between the peak value collagen/elastin and T1rho value(r=0.409,P<0.01).Conclusions(1)Adiabatic T1rho values are positively correlated with the progression of hepatic fibrosis in rats.(2)Adiabatic T1rho values may have some relationships with biological macromolecules such as ?-carotene(1006cm-1),collagen and elastin(1658cm-1).The concrete mechanism needs to be further studied.