Copyright ©The Author(s) 2019.
World J Gastroenterol. Feb 14, 2019; 25(6): 644-658
Published online Feb 14, 2019. doi: 10.3748/wjg.v25.i6.644
Table 1 Summary of magnetic resonance techniques used in primary sclerosing cholangitis
MR techniqueDescription of techniqueRole in PSC
T2-weighted MRCPNon-contrast sequences that depict fluid-filled structures such as bile ducts as high-intensity (white) compared to low-intensity (grey/black) of adjacent structures.Visualisation of biliary anatomy.
Three-dimensional MRCPRespiratory-triggered, single volume thin slab acquisitions producing isotropic images.Preferred sequences for optimal multi angle visualisation of the biliary anatomy.
Two-dimensional MRCPSpecific sequences combining coronal thin-slab and rotating oblique-coronal thick-slab image acquisition.Single shot T2w MRCP sequences are used when three-dimensional MRCP has artefacts or not feasible.
T2-weighted liver axialMeasure of T2 relaxation time in liver parenchyma. Both fat and water appear bright.Sequence for optimal visualisation of the liver parenchyma.
T1-weighted liver axialMeasure of T1 relaxation time in liver parenchyma. Fat appears bright, water appears dark.Sequence for optimal visualisation of the liver parenchyma.
MR elastrographyGenerates an elastogram map. Specific regions can be selected to obtain mean liver stiffness (kilopascals; kPa).Quantification and distribution of liver fibrosis.
Diffusion-weighted MRICaptures changes in the diffusion properties of water protons in tissue represented as the apparent diffusion coefficient.Can be used to assess liver parenchymal morphological changes (e.g., tumours) and as surrogate for liver fibrosis.
Dynamic contrast-enhanced MRIMeasures T1 changes in liver parenchyma following bolus administration of gadolinium in different phases of uptake and elimination.Delineates flow in vessels, permeability and enhancement of parenchyma. Can be used to quantify liver function using flow and permeability parameters as surrogate for liver fibrosis.
Table 2 Descriptive features of primary sclerosing cholangitis on magnetic resonance imaging/ magnetic resonance cholangiopancreatography[22,30-32]
Bile duct changes
Multiple annular or short segmental strictures (1-2 mm) with slightly dilated ducts among them: “beaded” appearance
Obliteration of small peripheral ducts “pruned tree”
Periductal inflammation
Thickening of walls of large ducts
Strictures seen at bile duct bifurcation
Angles between peripheral and central bile ducts become obtuse
Exclusive involvement of extrahepatic bile duct is infrequent
Bile duct dilatations are usually subtle
Retraction of papilla
Webs, diverticula and pigmented stones
Liver parenchymal changes
Segmental or lobular atrophy with compensatory hypertrophy attributed to chronic biliary obstruction
Patchy areas of peripheral parenchymal enhancement
Caudate lobe hypertrophy1
Spherical liver shape2
Peripheral wedge-shaped areas with focal increased signal intensity on T2-weighted images3
T2-weighted hyperintensity around portal vein branches
Regional changes
Gallbladder enlargement
Enlarged regional lymph nodes
Signs of portal hypertension including splenomegaly and collateral vessels
Table 3 The Amsterdam classification of endoscopic retrograde cholangiopancreatography cholangiographic changes in primary sclerosing cholangitis[65]
0No visible abnormalitiesNo visible abnormalities
IMultiple calibre changes; minimal dilatationSlight irregularities of duct contour; no stricture
IIMultiple strictures; saccular dilatations, decreased arborisationSegmental strictures
IIIOnly central branches filled despite adequate filling pressure; severe pruningStrictures of almost entire length of duct
IV-Extremely irregular margins; diverticulum-like outpouchings