Current status of peroral cholangioscopy in biliary tract diseases

Table 1 Comparison of different equipment for indirect peroral cholangioscopy

Characteristics	Spyglass	Polyscope
Optics resolution	6000 Pixel	10000 Pixel
Working channel	1.2 mm	1.2 mm
Viewing angle	70°	70°
Outer diameter	10 Fr	8 Fr
Re-useable	Yes	Yes
Optical channel hermetically close	No	Yes (The optical fiber doesn't need to be sterilized; this prolongs its life cycle)
Steerability	4 way	1 way (With locking of the bending and rotating of the tip)
Compatibility with existing endoscopy tower	No (You have to buy a complete endoscopy tower system)	Yes (You can use, through adapters an existing endoscopy tower in the Hospital)

Table 2 Diagnostic and therapeutic applications for cholangioscopy

Diagnostic applications		Therapeutic applications
Common	Uncommon	Common	Uncommon
Indeterminate biliary strictures	Biliary cyst evaluation	Lithotripsy for choledocholithiasis	Biliary guidewire placement
Verification of bile duct stone clearance	Bile duct ischemia evaluation (post-liver-transplant)		Transpapillary gallbladder drainage
Staging of cholangiocarcinoma	Ductal involvement in ampullary adenoma Hemobilia		Foreign body removal (e.g., stent)

Table 3 Results of cholangioscopic-guided biopsies in indeterminate lesions

Ref.	Sensitivity	Specificity	Negative predictive value	Accuracy
Ramchandani et al[17]	82%	82%	100%	82%
Chen et al[18]	49%	98%	72%	75%
Draganov et al[16]	76.5%	100%	69.2%	84.6%