Quantitative Evaluation Of The Degree Of Metabolic Associated Fatty Liver Disease By Magnetic Resonance IDEAL-IQ Sequence

Objective:Constructing a water lipid mixture model to test the accuracy and stability of magnetic resonance equipment and IDEAL-IQ sequence for fat quantification;Explore suitable scanning parameters for measuring liver fat content.Through clinical research,observe and analyze the correlation between MR liver fat quantification and other quantitative or semi quantitative imaging examinations and clinical related indicators,and explore the correlation between liver fat content in various liver segments and other organs.To provide more accurate quantitative diagnosis and efficacy evaluation information for clinical practice of fatty liver disease,in order to improve the diagnostic efficacy of metabolic related fatty liver disease.Methods:The first part is to construct a water-lipid mixture model,proportioning according to different concentration gradients,searching for suitable scanning parameters,and verifying the stability and accuracy of the MR equipment and sequence.The second part collected 28 patients with fatty liver and 26 normal volunteers who underwent liver magnetic resonance imaging（MRI）IDEAL-IQ sequence scanning from February 2022 to March 2023 for a comparative study:（1）The diagnostic efficacy of the MRI IDEAL-IQ sequence was determined by comparing it with ultrasound,CT values,CT liver spleen ratio,T1 phase difference and pathology;（2）Compare the liver fat content with serological indicators and other abdominal organ fat content,and study their correlation;Compare the differences in serum indicators and other abdominal organ fat content between the fatty liver group and the healthy volunteer group using liver fat content as the boundary standard;（3）Measure the fat content of each liver segment to explore whether there are liver segments that are prone to liver fat deposition.Results:The first part of two water-lipid model experiments showed a good linear correlation between the fat content measured by the magnetic resonance IDEAL-IQ sequence and the actual fat concentration.The regression equation was Y=0.979X+7.219,r²=0.980,and the appropriate scanning parameters were TR 6.5ms,TE3ms,layer thickness 10mm,excitation times 0.73,and flip angle-5°.The average liver MR fat content of 28 patients in the second part of the fatty liver group was16.72%±7.35%,and the mild,moderate,and severe components of the fatty liver group were 26%,59%,and 15%;The average value of MR liver fat content in the normal group was 3.38%±1.10%;（1）The liver fat content measured by magnetic resonance IDEAL-IQ sequence has a strong correlation with liver CT values,CT liver spleen ratio,and the difference in the same and opposite phase signals of magnetic resonance T₁,with correlation coefficients of-0.811,-0.850,and 0.850,respectively.The proportion of consistency with ultrasound and pathological examination results is87.5%and 100%,respectively There was a positive correlation between liver fat content and pancreatic and splenic fat content（r=0.340,0.415,P<0.05）.There was a significant statistical difference in pancreatic and splenic fat content between the healthy volunteer group and the fatty liver group（P<0.05）;There is a positive correlation between liver fat content and BMI（r=0.435,P<0.05）,and there are differences between groups;The liver fat content in the fatty liver group was positively correlated with alanine aminotransferase（ALT）and aspartate aminotransferase（AST）（r=0.340,0.415,P<0.05）,but only ALT showed intergroup differences in serological indicators,with no significant differences in other indicators;（3）By measuring the fat content of each liver segment and comparing the differences between groups,it was found that it is not possible to determine which liver segment is prone to fat deposition;（4）During the research process,it was also found that the IDEAL-IQ sequence of magnetic resonance imaging can differentiate pseudotumor signs caused by focal fatty liver.Conclusions:The IDEAL-IQ sequence of magnetic resonance imaging can quantitatively analyze liver fat content,which has good consistency and more accurate quantitative ability with existing pathological and imaging evaluation methods.It can also accurately locate fat and distinguish focal fatty liver;There is a correlation between liver fat content and pancreatic and splenic fat content,BMI,and ALT,which may be related to lipid accumulation and metabolism,as well as damage to liver cells after adipose transformation;The IDEAL-IQ sequence of magnetic resonance imaging has certain advantages over other imaging methods in the quantitative diagnosis of fat,providing assistance for the prevention and treatment of fatty liver,especially for the clinical work of efficacy evaluation,and has good feasibility.