Table 2.

Major utility of different imaging techniques

Techniques	Utility
Ultrasound	Detection of bile duct dilation
	Differentiation from a stone
EUS/IDUS	Assessing the depth of invasion and lymph node involvement
CT/MRI	Detect tumors larger than 1 cm and bile duct dilation
	Differentiation from conventional cholangiocarcinoma
Cholangiography	Define the extent of tumors
	Detection and drainage of mucin in ERC and PTC
Cholangioscopy	Confirm the histology and extent of lesions
	Adjuvant treatments
PET/CT	Detection of unsuspected distant metastases

EUS: Endoscopic ultrasonography; IDUS: Intraductal ultrasonography; ERC: Endoscopic retrograde cholangiography; PTC: Percutaneous transhepatic cholangiography; CT: Computed tomography; MRI: Magnetic resonance image; PET: Positron emission tomography.