Table 1 CT/MRI features of primary biliary cholangitis
From: CT and MR imaging of primary biliary cholangitis: a pictorial review
CT/MRI features | Definition | Pathological basis | Clinical significance | CT | MRI |
|---|---|---|---|---|---|
Morphological abnormalities | |||||
Hepatomegaly [37] | Subjective abnormal diffuse enlargement of the liver supplemented by lineal craniocaudal measurement | Intrahepatic cholestasis, hepatocyte edema, degeneration, massive inflammatory cell infiltration | Found in 11 to 50% of PBCs, the percentage tends to decrease with increasing stage | + | + |
Nodular liver margin (with nodules < 3 cm) | Diffuse regenerative nodules | Found in 64% of cirrhosis caused by PBC, correlated with advanced stages, used to differentiate stage I-II from stage III-IV fibrosis | + | + | |
Disproportionate liver lobes due to a combination of segmental atrophy and/or hypertrophy | Altered segmental portal venous perfusion | Segmental atrophy often found in late cirrhosis, less common than viral hepatitis; segmental hypertrophy is common in PBC with stage IV fibrosis | + | + | |
Parenchymal abnormalities | |||||
Lace-like or patchy density or signal abnormalities in liver parenchyma | Parenchymal necro-inflammatory changes or fibrosis and perfusion changes secondary to destruction of portal vein branches | Degree of heterogeneity on T2WI correlated with fibrosis stages | − / + | + | |
Periportal halo sign [42] | 0.5–1.0 cm rounded low signal intensity lesion centred on a portal vein branch on T1WI and T2WI | Fibrous tissue deposition or cellular depletion around the portal triads | The most typical feature of PBC, associated with advanced stages | − | + |
Periportal edema [43] | Low-density on CT or hyperintensity on T2WI around portal venous branches | Portal tract inflammation with infiltration of lymphocytes and plasma cells, associated with interfacial hepatitis | Found in 80–100% of early-stage PBC and 66.7% of PBC with stage IV fibrosis, controversial correlation with fibrosis stage | + | + |
Irregular configuration of the biliary ducts [43] | Segmental bile duct dilatation, stenosis or poor visualization, mostly involving the intrahepatic secondary bile ducts | Non-suppurative destructive cholangitis | Usually represents more advanced disease, useful for differentiation with PSC | − / + | + |
≥ 2 lymph nodes with ≥ 1 cm on the short axis | Benign reactive hyperplasia of lymph nodes | Found in 62–88% of PBC, located in periportal, gastrohepatic ligament, retroperitoneal, paracardial space and in mesentery, not associated with fibrosis stage or inflammation grade | + | + | |
Portal hypertension | |||||
Portal vein diameter > 13 mm | Distortion of hepatic vascular architecture and dynamic changes result in increased resistance to portal blood flow | Can occur in non-cirrhotic stages, associated with histological grade, treatment response and prognosis Splenomegaly may be the first imaging feature captured in PBC, while other signs are more relevant to advanced stages | + | + | |
Increased number and size of vessels around splenic hilum, paraesophageal region, and gastrohepatic ligament | − / + | + | |||
Craniocaudal diameter of the spleen ≥ 13 cm | + | + | |||
Complications of cirrhosis [11] | Ascites, spontaneous bacterial peritonitis, and HCC development | Portal hypertension and resultant circulation disturbance cause ascites; liver and immune dysfunction cause spontaneous bacterial peritonitis | PBC with baseline cirrhosis is a strong predictor of worse long-term outcomes and should consider liver transplantation once symptoms fail to resolve | + | + |
Liver stiffness quantification [46] | Liver stiffness measured by elastography | Hepatic fibrosis and cirrhosis | Used to identify advanced fibrosis of PBC, liver stiffness > 4.30 kPa is a risk factor for cirrhotic decompensation in patients receiving UDCA | − | + |
Semi-quantitative parameters (C (max), T (max) and T (1/2)) and model-free parameters (HEF, irBF, MTT) Mean relative signal enhancement in the liver and mean contrast to noise ratio of the common bile duct | Gadoxetic acid-enhanced MRI visualizes the impairment of hepatocyte function through the uptake and excretion of contrast in the liver parenchyma and bile ducts | Significant differences in several quantitative parameters on gadoxetic acid-enhanced MRI among PBC, postherpetic cirrhosis (other etiologies) and healthy subjects The ability of gadoxetic acid-enhanced MRI in differentiating cirrhosis of different etiologies needs further investigation | − | + | |