Table 2.

Differential diagnosis table for IgG4-Related Disease.

	Primary sclerosing cholangitis	Systemic vasculitis – Takayasu’s and ANCA-associated	Cholangiocarcinoma	Hepatitis	IgG4-related autoimmune disease
XR	Not generally utilized	Angiogram may show stenosis and occlusion	Not generally utilized	Not generally utilized	Not generally utilized
US	Thickening bile duct walls Biliary dilatation	Shows mural thickening Mural layering reflecting inflammation	Can detect mass Biliary obstruction	Enlarged liver Diffuse decrease parenchymal echogenicity Increase echogenicity portal vein walls (“Starry night” pattern) Can have normal liver echogenicity	Biliary stricture and mural thickening Biliary dilatation
CT	Thickening and enhancement bile duct wall Focal, peripheral intrahepatic biliary dilatation	Mural thickening Mural enhancement Luminal narrowing	Mass with irregular peripheral enhancement Diffuse periductal thickening Abnormal dilated or irregular narrowed duct	Hepatomegaly Periportal edema Heterogenous enhancement Regions low attenuation	Biliary dilatation and mural thickening Autoimmune pancreatitis
MRI	T1: Normal signal intensity T2: Multifocal short strictures with intervening biliary dilatation resulting in a beaded appearance DWI: Biliary stricture with restricted diffusion	T1: Normal signal intensity T2: Vessel wall edema intense DWI: Mural inflammation with restricted diffusion	T1: Normal or low intensity T2: Hyperintense mass Overlying capsular retraction Strictures irregular margins, asymmetric arrowing DWI: Mass with restricted diffusion	T1: Normal or decreased signal intensity T2: Periportal edema high signal Parenchyma edema high signal intensity Absent biliary stricture DWI: Parenchymal inflammation with restricted diffusion	T1: Normal or decreased signal intensity pancreas Normal or decreased signal intensity hepatic inflammation T2: Biliary involvement as solitary structure with periportal soft tissue Often with autoimmune pancreatitis Focal hepatic inflammation DWI: Biliary stricture wall with restricted diffusion
Contrast Enhancement	Absent periductal soft tissue	Mural enhancement Involves aorta frequently	Delayed centripetal enhancement Overlying capsular retraction Vascular encasement Satellite nodules Less well-defined, often branching spiculated lesion	Heterogenous contrast enhancement	Vasculitis involving aorta branch vessels
PET	Not generally used	Metabolically active perivascular tissue	Metabolically active mass	Not generally used	Not generally used