[Application value of diffusion-weighted imaging in ischemic-type biliary lesions after liver transplantation]

To discuss the application values of DWI (diffusion-weighted imaging) and ADC (apparent diffusion coefficient) on ischemic-type biliary lesions (ITBL) after orthotopic liver transplantation.

According to whether there was ITBL after liver transplantation or not, 46 cases of liver transplantation were selected and divided into 2 groups on the basis of PTC (percutaneous transhepatic cholangiography) or ERCP (endoscopic retrograde cholangiopancreatography) examination, pathology or clinical follow-up data: ITBL group (n = 29) and no ITBL group (C group, n = 17). The ADC value was measured for right lobe of graft liver parenchyma (b value = 600 s/mm(2)). And the signal of biliary system of graft on DWI and biliary tract on MRCP were analyzed.

(1) The ADC values of liver graft were (1.456 ± 0.286) × 10(-3) mm(2)/s and (1.716 ± 0.391) × 10(-3) mm(2)/s in ITBL and C groups respectively. The difference in ADC value was significant between two groups (P = 0.015); (2) the incidence of increased signal of bile duct on DWI was 82.8% (24/29) and 5.9% (1/17) for ITBL and C groups respectively. The lesion was located in porta hepatis and intrahepatic small bile duct was seen in 17 of 24 patients (70.8%) in ITBL group. The difference was significant in signal of bile ducts between ITBL and C groups (P < 0.001). Twenty-one cases with sludge on DWI in ITBL group had hyperintensity, isointensity or hypointensity. There was no abnormal signal in the lumen of bile duct in C group.

The major sign of ITBL is a hyperintensity of porta hepatis and small bile ducts on DWI. And the ADC value of graft liver parenchyma decreases. These reflect the pathological changes to an extent and may be an effective and sensitive monitoring tool of early ITBL. DWI is a novel, non-invasive, simple and practical method in the diagnosis and differential diagnosis of ITBL after liver transplantation.