| Part I MR Multi Echo Dixon and HISTO Technology Quantitative Liver Iron Overload on A Rabbit ModelObjective:To explore the feasibility and accuracy of MRI(Magnetic Resonance Imaging)multi-echo Dixon and HISTO sequences to quantify liver iron overload.Materials and Methods:Twenty-nine New Zealand white rabbits were randomly divided into 21 in the high-speed rail group and 8 in the control group.The highspeed rail group was injected intramuscularly with iron dextran 15 mg/kg every week for 21 weeks.Perform MR multi-echo qDixon-WIP,HISTO and traditional GRE sequence scans every week to measure ME Dixon-R2*,GRE-R2*,HISTOR2water,HISTO-H-R2water values.Prussian blue staining was used to observe the distribution of liver iron deposits,and the liver iron content(LIC)was obtained by atomic spectrophotometer.Pearson or Spearman correlation analysis was used to evaluate the correlation between fat ME Dixon-R2*,GRE-R2*,HISTO-R2water and HISTO-H-R2water values and LIC.Draw receiver operating characteristic(ROC)to analyze the diagnostic efficacy and differences of MRI sequences for liver iron content.Result:(1)The HISTO-R2water,HISTO-H-R2water,ME Dixon-R2*,GRE-R2*measured by MR of rabbit liver in the high-speed rail group(21 rabbits)were significantly higher than those of the control group(8 rabbits).There were statistics between the two groups Academic difference(P<0.05).(2)Measured by MR scan of all experimental rabbits:ME Dixon-R2*and LIC are significantly positively correlated(r=0.94,P<0.01),and the linear regression equation is established as follows:y=0.023x-1.400(F=204.0,P<0.001);There was a significant positive correlation between GRE-R2*and LIC(r=0.95,P<0.001).The linear regression equation was established as:y=0.013x-0.516(F=252.5,P<0.05);HISTO-There is a moderate positive correlation between H-R2water and LIC(r value is 0.51,P<0.001),and the linear regression equation is established:y=0.093x-2.215(F=9.4,P<0.05);HISTO-R2water and LFC There is no correlation between them(P=0.329).(3)Perform ROC analysis.When LIC=1.8mg/g dry weight,the corresponding AUC of HISTO-R2water,HISTOH-R2water,ME Dixon-R2*and GRE-R2*values are 0.744(P=0.038),0.983(P<0.001),0.994(P<0.001),0.994(P<0.001).The best cut-off values are 45.25(1/S),60.40(1/S),180.45(1/S),234.19(1/S);the diagnostic sensitivity is 0.550,1.000,0.923,0.950;the specificity is respectively It is 1.000,0.889,0.950,1.000.(4)When LIC=3.2mg/g dry weight,the corresponding AUC of HISTO-R2water,HISTO-H-R2water,ME Dixon-R2*and GRE-R2*values are 0.583(P=0.452)and 0.917(P<0.001),0.995(P<0.001),1.000(P<0.001).The best cut-off values are 43.10,84.05(1/S),268.70(1/S),320.78(1/S),the diagnostic sensitivity is 0.588,0.824,0.941,1.000,and the specificity is 0.667,0.917,1.000,1.000.At this time,the diagnostic efficiency of HISTO-R2water was poor(P>0.05).(5)When LIC=7.0mg/g dry weight,the corresponding AUC of HISTO-R2water,HISTO-H-R2water,ME Dixon-R2*and GRE-R2*values are 0.280(P=0.071),0.643(P=0.242),0.964(P<0.001),1.000(P<0.001).The best cut-off values of HISTO-R2water,HISTO-H-R2water,ME Dixon-R2*and GRE-R2*are 36.25(1/S),60.40(1/S),396.80(1/S),629.33(1/S),and the diagnostic sensitivity is 0.750,1.000,0.880,1.000,the specificity is 0.250,0.380,1.000,1.000,respectively.Conclusion:The qDixon-WIP sequence can noninvasively,quickly,accurately quantify and grade liver iron overload,and its diagnostic efficiency is comparable to the traditional GRE sequence,and it is better than the HISTO sequence.Part Ⅱ MR Multi Echo Dixon and HISTO Technology Quantitative Study of Liver Iron Overload Combined with Fatty on A Rabbit ModelObjective:To explore the feasibility and accuracy of multi-echo Dixon and HISTO sequences for simultaneous quantification of liver fat and iron.Materials and Methods:Thirty-eight New Zealand white rabbits were randomly divided into 30 high-fat and high-iron groups and 8 control groups.The high-fat and high-iron groups were fed with high-fat diet and injected intramuscularly with iron dextran 15 mg/kg every week.Perform MR multi-echo qDixon-WIP and HISTO sequence scans every week to measure ME Dixon-R2*,HISTO-R2water,HISTO-H-R2water values and ME Dixon-PDFF,HISTO-PDFF,HISTO-H-PDFF values.HE staining and Prussian blue staining were used to observe liver steatosis and iron deposition distribution,and obtained by atomic spectrophotometer and chemical extraction to obtain LIC and liver fat content(LFC).Use Pearson or Spearman correlation analysis to evaluate the correlation between ME Dixon-R2*,GRE-R2*,HISTO-R2water and HISTO-H-R2water values and LIC,analyze and evaluate ME Dixon-PDFF,HISTO-PDFF,HISTO-H-Correlation between PDFF and LFC.Draw ROC,analyze the diagnostic efficiency and difference of each sequence of MRI for liver iron content and fat content.Result:(1)The HISTO-R2water,HISTO-H-R2water and ME Dixon-R2*values measured by MR in the high-fat and high-iron group(25 rabbits)were:46.68± 10.21(1/s),80.13±19.73(1)/s),240.13±105.38(1/s),the HISTO-R2water,HISTO-H-R2water,ME Dixon-R2*values measured by MR of rabbit liver in the normal control group(8)were 38.51 ±4.21(1/s),43.70±3.61(1/s),70.39± 19.03(1/s),there were statistical differences between the two groups(P<0.05).(2)There is no correlation between HISTO-R2water and LIC in all 33 experimental rabbits(P>0.05).HISTO-H-R2water is significantly positively correlated with LIC(r value is 0.89,P<0.01).The linear regression equation is:y=0.1x-3.71(F=119.90,P<0.05);ME Dixon-R2*is significantly positively correlated with LIC(r=0.94,P<0.01),the linear regression equation is:y=0.02x-0.81(F=235.56,P<0.05).(3)Perform ROC analysis,when LIC=1.8mg/g dry weight,HISTO-R2water,HISTOH-R2water,ME Dixon-R2*value AUC are 0.654(P=0.141),0.946(P<0.001),0.954(P<0.001).The best cut-off values were 48.15(1/S),63.30(1/S)and 151.98(1/S),the sensitivity of diagnosis was 0.55,0.90 and 0.90,and the specificity of diagnosis was 0.92,0.92 and 1.00,respectively.At this time,the diagnostic efficiency of HISTO-R2water is poor(P greater than 0.05).When LIC=3.2mg/g dry weight,HISTO-R2water,HISTO-H-R2water,ME Dixon-R2*value AUC are 0.646(P=0.161),0.958(P<0.001),0.996(P<0.001).The best cut-off values were 50.89(1/S),81.65(1/S)and 246.18(1/S),the diagnostic sensitivity was 0.54,1.00 and 1.00,and the specificity was 0.85,0.85 and 0.95,respectively.When LIC=7.0mg/g dry weight,HISTO-R2water,HISTO-H-R2water and ME DixonR2*AUC are 0.599(P=0.161),0.974(P<0.05),0.948(P<0.05),respectively.The best cut-off values were 55.65(1/S),95.85(1/S)and 324.03(1/S),the diagnostic sensitivity was 0.50,1.00 and 1.00,and the specificity was 0.93,0.97 and 0.90,respectively.HISTO-R2water has poor diagnostic efficiency for LIC at all levels(P>0.05).(4)33 experimental rabbits HISTO-PDFF and LFC are moderately positively correlated(r value is 0.54,P<0.01),HISTO-H-PDFF and LFC are highly positively correlated(r value is 0.63,P<0.01),ME Dixon-PDFF was significantly positively correlated with LFC(r=0.85,P<0.01).(5)Do liver fat ROC curve analysis:when LFC=5%,the best cut-off values of HISTO-PDFF,HISTO-H-PDFF and ME Dixon-PDFF are 4%,3.9%and 3.05%,respectively,the sensitivity of diagnosis They are 1.00,1.00 and 1.00,and the specificity of diagnosis is 1.00,1.00 and 1.00 respectively.The AUC were 1.000(P<0.001),1.000(P<0.001),and 1.000(P<0.001).At this time,each sequence has high diagnostic efficiency for fatty liver.When LFC=10%,HISTO-PDFF,HISTO-HPDFF and ME Dixon-PDFF AUC are 0.688(P=0.071),0.688(P=0.071),0.838(P<0.05),and the best cut-off values are respectively They were 8.38%,6.93%,and 7.11%,the diagnostic sensitivity was 0.77,0.77,and 1.00,and the specificity was 0.55,0.55,and 0.60.At this time,HISTO-PDFF and HISTO-H-PDFF had poor diagnostic efficiency for liver fat content(P>0.05).Conclusion:The qDixon-WIP sequence can accurately quantify and grade liver iron overload with fatty liver.It has a higher diagnostic efficiency and is superior to the HISTO sequence.Excessive iron deposition will affect the accuracy of the HISTO sequence to quantify liver fat content.Part Ⅲ Multi Echo Dixon Technique Quantitative Study of Liver Iron Overload in Patients with ThalassemiaObjective:To explore the feasibility and effective range of qDixon-WIP sequence in the 3.0T MR device to quantify liver iron concentration in patients with thalassemia,and to analyze the prevalence of fatty liver in patients with thalassemia.Materials and Methods:Collect 36 thalassemia patients who came to the First Affiliated Hospital of Guangxi Medical University from August 2020 to December 2020.They underwent 3.0T MR examination and measured GRE-T2*,ME Dixon-R2*and ME Dixon-PDFF value.Result:There were 15 males and 21 females,aged from 5 to 59 years old,with a median age of 15.4 years.The range of GRE-T2*measured by CMR-tools software in 36 thalassemia patients was 1.51-15.12ms,and the median was 4.21ms(2.99-5.54ms).There were 12,12,10,and 2 patients with normal,mild,moderate,and severe liver iron deposition,respectively.GRE-R2*of 36 patients was 346.74±172.79(1/s)(66.14-662.25/s),ME Dixon-R2*was 339.27±162.77(1/s)(41.85-633.44/s).There was no correlation between the age of 36 thalassemia patients and the values of SF,liver GRE-R2*,ME Dixon-R2*(r=0.144,P=0.492;r=0.218,P=0.296;r=-0.018,P=0.931;).There was no correlation between SF and liver GRE-R2*and ME Dixon-R2*values(r=0.104,P=0.622;r=0.141,P=0.501;r=-0.18,P=0.931;).There is a significant positive linear correlation between the liver GRE-R2*and ME Dixon-R2*values(r=0.94,P<0.001),and the linear regression equation is:y=0.996x+8.835.The Bland-Altman method analyzed that the GRE-R2*and ME Dixon-R2*values were highly consistent,and the intraclass correlation coefficient(ICC)was 0.967(95%CI,0.936-0.983).The ME Dixon-PDFF measured in 36 thalassemia patients was 0.50-15.90%,with a median of 2.20%.Conclusion:The MR multi-echo qDixon-WIP sequence can quickly and accurately quantify liver iron content,which is comparable to the traditional GRE sequence,and it can also energize liver fat. |
