Imaging pancreatobiliary ductal system with optical coherence tomography: A review

Table 2 Comparison of various imaging modalities

Imaging modality	PTC	ERCP	MRCP	US/HFUS/EUS/IDUS	CT	OCT
Projection/ tomograph	Projection	Projection	Projection or tomographic	Tomographic	Tomographic	Projection or tomographic
Resolution	1-2 mm	1-2 mm	Fairly poor 3-5 mm	US/EUS 100-250 μmHFUS/IDUS 50-100 μm	300-500 μmμCT: 3-125 μm	Fairly high1-10 μm
Imaging depth	1-5 mm	5-60 mm	Entire biliary tree	US/EUS: 5-10 cmHFUS/IDUS: 1-3 cm	Entire biliary tree	1-3 mm
Tissue sampling	+ +	+ + +	-	US +EUS + + +	+	-
Portability	-	+	-	US + + +EUS + +	-	+ +
Therapy	+ + +	+ + +	-	US -EUS +	-	+
System cost	+ +	+ + + +	+ + +	US - EUS + +	+ +	+ +
Operator dependence	High	High	Low	Very high	Low	Low
Staging of malignancy	-	-	+ +	US +EUS + + +	+ + +	-
Safety	-	+	+ + +	+ +	+ +	+++
Experiment duration	2-4 h	30-120 min	10-30 min	20-40 min	15-30 s	5-10 min
Complications	+ + +Risk (5%-10%) of Infection, bleeding and bile leaks	+ +Risk (< 5%) Bleeding, perforationpancreatitis cholangitis	-Claustrophobia in some patients	+Risk (1%) of failure rate, bleeding and perforation	-Rare allergic reaction (< 1%) to iodinated agents	-No complication
Comments pros	+ Diagnosis and therapeutic (treatment) procedure	+ Diagnosis and treatment procedure	Non-invasive+ No ionizing radiation+ Relatively operator -independent	Usually non-invasive (sedation)+ Diagnosis tool combined with tissue and/or lesion sampling	Non-invasive+ Faster method+ High resolution+ Operator-independent	Non-invasive+ No ionizing radiation+ High resolution+ Faster method+ Operator-independent
Cons	Invasive ionizing radiationOperator- dependent	InvasiveIonizing radiationOperator dependent	Expensive-poor resolutionSolely diagnostic methodMotion sensitiveclaustrophobia	Operator dependentHighly motion sensitiveThermal effects and cavitations	Ionizing radiationSolely diagnostic method	Low imaging depth 3 mmMotion sensitive

PTC: Percutaneous transhepatic cholangiography; ERCP: Endoscopic retrograde cholangiopancheatography; MRCP: Magnetic resonance cholangiopancreatography; US: Ultrasound; EUS: Endoscopic ultrasound; HFUS: High frequency ultrasound (> 10 MHz); IDUS: Intraductal ultrasonography; CT: Computed tomography; OCT: Optical coherence tomography.