| Objective1.To compare the difference between three-dimensional volume interpolated body examination(3D-VIBE)and three-dimensional T1-weighted fast low-angle shot(3D-FLASH)on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid(Gd-EOB-DTPA)enhanced Magnetic resonance imaging(CE-MRI)in the assessment of biliary tract quality and the visualization of biliary stricture(BS)after liver transplantation.Optimal scanning protocols have been explored.2.To evaluate the application value of CE-MRI in evaluating the liver function of BS and different drainage areas,and to provide reliable imaging evidence for patients with BS after liver transplantation.MethodsA total of 60 patients with clinically and ultrasound examination suspected BS after liver transplantation underwent Gd-EOB-DTPA contrast-enhanced magnetic resonance cholangiography(CE-MRC)in our hospital from January2018 to December 2022.These included conventional MRI dynamic contrast-enhanced imaging,T2-weighted magnetic resonance cholangiography(T2W-MRC),axial 3D-VIBE and coronal 3D-FLASH sequence at 20 minutes after Gd-EOB-DTPA injection,which is the hepatobiliary phase(HBP).If less contrast agent was discharged into the biliary tract,delays of 60,90 and 120 minutes were added to visualize the biliary tract.All patients underwent biochemical tests and Model for End-Stage Liver Disease(MELD)score within1 week before MRI examination.All MRI results were independently reviewed by two radiologists.The3D-VIBE and 3D-FLASH sequences were measured and analyzed for qualitative and quantitative assessment of biliary tract quality.For qualitative evaluation,a 4-point Likert scale was used to score the degree of display in each region of the biliary tract.For quantitative evaluation,the signal noise ratio(SNR)and contrast noise ratio(CNR)of different image sequences are compared.The differences between T2W-MRC,3D-VIBE and 3D-FLASH sequences in diagnosis of BS degree and diameter are evaluated separately.BS is classified as mild,moderate and severe depending on the extent of stenosis.Correlation between the relative enhancement(RE)of liver and BS degree,different biochemical tests,and MELD score.Results1.Clinical data: a total of 40 patients were enrolled,including 28 males and12 females,aged from 31 to 73 years,with an average age of(54.70±9.80)years.2.Quality evaluation: the qualitative score of biliary tract in 3D-FLASH sequence was higher than that in 3D-VIBE sequence(all P<0.05).The SNR and CNR of 3D-FLASH were significantly higher than those of 3D-VIBE(all P<0.05).3.BS evaluation: there was no significant difference in the diameter of BS between T2W-MRC,3D-VIBE and 3D-FLASH groups(P>0.05).The diameter of BS in the severe group was significantly different among T2W-MRC,3D-VIBE and 3D-FLASH groups(P=0.011<0.05).Forty patients had a total of 47 BS(including 1 patient with 4 nonanastomotic strictures and 4 patients with 2anastomotic strictures),of which 14 patients had mild BS(grade 1),16 patients had moderate BS(grade 2),and 17 patients had severe BS(grade 3).4.Liver function Evaluation: RE was negatively correlated with AST,ALP,bilirubin and MELD score(all P<0.001).HBP severe BS had lower RE values than moderate and mild BS.There was significant difference between mild BS and severe BS(P<0.001),moderate BS and severe BS(P=0.003<0.01),but there was no significant difference between mild BS and moderate BS(P=0.099>0.05).Conclusions1.Both CE-MRC 3D-VIBE and 3D-FLASH sequences can be applied to biliary tract quality and the visualization of BS.The image quality of 3D-FLASH is better than that of 3D-VIBE,and the effect of BS after liver transplantation is better.2.CE-MRC provides theoretical support for the selection of clinical treatment options by not only accurately determining the extent of BS,but also evaluating liver function in different drainage areas of BS. |
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