The Investigation Of Clinical Application Of Quantitative Computed Tomography In The Quantitative Evaluation Of Fatty Liver

Object: To investigate the value of clinical application of Quantitative Computed Tomography(QCT) in quantitative diagnosing of fatty liver. Methods: From June to September at 2015, a total of 113 cases with fatty liver and 17 cases of normal liver underwent abdominal non-enhanced CT scan in affiliated hospital of Guizhou Medical University, age 19-80 years old. The patients were asked about the disease history to confirm without any positive feature, such as virus hepatitis, hepatocellular cancer, autoimmune steatosis and so on. Besides this, all patients had no abnormal biochemical parameters. All patients received abdominal non-enhanced CT scan with SIEMENS 64-row CT scan which is cushioned with QCT solid phantom made by Mindways Company. The scanning technology parameters were obtained by qualitive assurance phantom. After collecting all patients’ CT data, all images were sent to PACS. The Bone Mineral Density(BMD) of liver, the slope value and the value of Field-Uniformity Correction(FUC) of all patients were acquired from QCT Pro work station and plugged into the fatty content formula to get the lipid content of liver(β-value) of all cases. The formula is as follows:(1)Observed BMD=BMD/FUC(2) Expected liver HU=1047.9+(slope+0.2174)*4.842-999.6(3)Expected Fat HU=942.9+(slope+0.2174)*(-31.42)-999.6(4)Expected liver BMD=Expected liver HU/slope(5)Expected Fat BMD=Expected Fat HU/slope(6)Beta=(Expected Liver BMD-Observed BMD)/(Expected Liver BMD-Expected Fat BMD).The difference of the mean value of CT, BMD and β-value in the liver of mild, moderate and severe grades of fatty liver groups and a control group were compared and the statistical correlations among these indicators was analyzed with SPSS19.0 software. Results: There was significant difference among the average value of CT, BMD and the β-value in the liver of mild, moderate and severe grades of fatty liver groups and control group(p<0.05, respectively). The 95% confidence intervals of the β-value in each group(the control group and mild, moderate, severe grades of fatty liver groups) could be demonstrated as [-0.0474,-0.0043]、[0.0481, 0.0642]、[0.0960, 0.1276]、[0.1994, 0.2442]. There were obvious correlations demonstrated between the average CT value and average BMD of liver, the average CT value and average β-value of liver, the average β-value and ratio of liver-spleen(L/S)(r = 0.976,-0.977,-0.959 respectively, all p<0.05, both side). The β-value has a highly sensitivity(0.912) and specificity(0.882) in the quantitative diagnose of fatty liver. Conclusion: The β-value acquired from formula detected the fatty content of the liver is feasible to quantitatively detect fatty liver.