| Objective:To investigate the potential application of diffusion-weighted magnetic resonance(MR)imaging(DW imaging)in evaluating the liver function in calculus obstruction using the apparent diffusion coefficient(ADC).Materials and Methods:1.Clinical and Patients groupThis study was conducted at Lanzhou university second hospital between September and November 2011.A total of 24 patients(14 female,10 male;average age,57 years)and 7 healthy controls(4 female,3 male;average age,67 years)with completely normal liver.The 24 patients were divided into three groups based on the content of total bilirubin in the serum(mild group,34-170 ummo/l;moderate group,170-340 ummol/l;severe group,>340 ummo/l).2.Examination Methods2.1 The patients were examined using a 3.0 Tesla(T)8 channel system(Magnetom verio Syngo MR 317;Siemens Medical Solutions,Erlangen,Germany)with a 45 mT/in gradient strength and a 12-element surface phased-array coil.Sequence parameters were as follows:repetition time(TR),5900 ms;echo time(TE),83 ms;acquisition matrix,115×192;field of view,284×376 mm;slice thickness/gap,6.59/1 mm,30 slices,2 averages.The b-values of 0,400,and 800 s/mm2 were adopted with a scan time of approximately 3-5 minutes(depending on the respiratory cycle).2.2 Laboratory biochemical tests including total bilirubin(TB),conjugated bilirubin(CB),transaminases(AST&ALT),alkaline phosphatase(ALP),and ?-glutamyltransferase(?-GGT),which are markers for hepatic function,were performed on 24 patients and 7 controls.3.Imaging DiagnosisQuantitative analysis was performed using a freestanding MR workstation(Leonardo;Siemens Medical Solutions,Erlangen,Germany).ADCs of liver parenchyma were calculated from the ADC maps using regions of interest(ROIs)placed on the right lobe of the liver(the left hepatic lobe was not assessed due to the risk of cardiac motion artifacts).Vessels and artifacts were avoided in ROI placement.Each measuring circle was approximately 1.0 cm in diameter with an average pixel number of 776.Identical ROIs were applied to corresponding ADC maps.4.Statistical MethodsSPSS(Statistical Package for Social Sciences)12.0 was used for statistical analysis.One-way ANOVA was used to compare the acquired ADCs calculated with b-values of 400 and 800 s/mm2 between the control group and the mild,moderate,and severe groups.Pearson correlation coefficient was determined to investigate the association between DWI parameters and hepatic functional laboratory index.Results:1.Surgery confirmed choledocholith;2.There were statistically significant differences between the control group and the mild,moderate and severe groups(P<0.05).However,there was no significant difference between the mild group and the moderate group(P>0.05).There wre statistically difference in each group before and after surgery.There were statistically significant correlations between TBIL,DBIL,ALP,GGT,and ADCs(P<0.01),especially between ADCs and TBIL,DBIL and ALP(r=-0.753,-0.733,and-0.708,respectively,P<0.01).However,there was no significant correlation between ADCs and ALT(r=-0.2 12,P<0.01).Conclusion1.DWI have the potential for use to analyze the liver function in calculus obstructive jaundice patients.2.The ADC value can indicate the damage degree of hepatic cells.There is significant negative correlation between the serum bilirubin and the ADC values. |
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