ABSTRACT
Objective To investigate the feasibility of energy spectrum CT material separation technology for quantitative evaluation of nonalcoholic fatty liver patients,to compare the accuracy of this method with the conventional liver/spleen CT ratio for grading liver fat content.Methods Sixty patients diagnosed with nonalcoholic fatty liver and 20 healthy volunteers were chosen to undergo liver MR multi-echo(ME)Dixon and energy spectrum CT scans.The proton density fat fraction(PDFF),fat concentration(FC),and liver/spleen CT ratio were then measured for each participant.According to PDFF,nonalcoholic fatty liver patients were divided into mild fatty liver group,moderate fatty liver group,and severe fatty liver group.Results With the increase in PDFF,FC increased and the liver/spleen CT ratio decreased.The difference between FC groups in normal,mild,moderate and severe fatty liver groups was statistically significant(P<0.05),while the difference between the liver/spleen CT ratio of normal group and mild fatty liver group was not statistically significant(P>0.05).The receiver operating characteristic(ROC)curve analysis showed that when the critical value of FC was 351.19 mg/mL,the sensitivity,specificity and area under the curve for normal group and fatty liver group were 0.95,0.1 and 0.99,respectively.Conclusion The energy spectrum CT material separation technology has a good correlation between the fat content measured by the MR ME Dixon,which is superior to the fat content measured by the liver/spleen CT ratio.For patients with nonalcoholic fatty liver,FC in energy spectrum CT has high accuracy in differentiating normal and mild fatty liver.