Comparative analysis of ERCP, IDUS, EUS and CT in predicting malignant bile duct strictures

Table 1 Baseline characteristics of the patient cohort n (%)

Variable	Value
Patients, n	234
Median age, yr (IQR)	64 (54-73)
Age range, yr	20-90
Sex (M/F)	127/107
ERCP + IDUS performed, n	234
ETP performed	194 (83)
EUS performed, n	234
CT performed, n	234
Median follow-up, mo (IQR)	34 (19-52)
Follow-up range, mo	12-100
Procedures, n
Clinical follow-up	50
Surgery	161
Palliative therapy	23
Localization of stricture (CBD)
Proximal third	28 (12)
Middle third	21 (9)
Distal third	185 (79)
Final diagnosis (n)
Benign disease	98
Normal bile duct	10
Papillitis	15
Ampullary adenoma	8
Cholangitis	10
PSC	3
Mirizzi syndrome	3
Choledocholithiasis	2
Pancreatitis	39
Pseudocyst	2
Choledochal adenofibroma	1
IPMN	2
Choledochal cyst	1
Pancreatic cystadenoma	1
Caroli’s syndrome	1
Malignant disease	136
Cholangiocarcinoma	56
Pancreatic carcinoma	55
Ampullary carcinoma	19
Gallbladder carcinoma	3
Hepatocellular carcinoma	3

IQR: Interquartile range; CBD: Common bile duct; PSC: Primary sclerosing cholangitis; M: Male; F: Female.

Table 2 Diagnostic indices predicting malignant bile duct stenosis

Index	Diagnostic parameter
	ERCP/IDUS			ETP			IDUS + ETP			EUS			CT
	95%CI			95%CI			95%CI			95%CI			95%CI
All patients
Sensitivity	93%	88-97	126/136	37%	29-45	47/127	94%	90-98	128/136	71%	63-78	96/136	67%	59-75	91/136
Specificity	89%	83-95	87/98	100%	NA	67/67	89%	83-95	87/98	78%	69-86	76/98	82%	74-89	80/98
Accuracy	91%	87-95	213/234	59%	52-66	114/194	92%	88-95	215/234	74%	68-79	172/234	73%	67-79	171/234
Subgroup only considering CCC as a malignancy
Sensitivity	96%	92-100	54/56	42%	29-55	23/55	96%	92-100	54/56	57%	44-70	32/56	73%	62-85	41/56
Specificity	89%	83-95	87/98	100%	NA	67/67	89%	83-95	87/98	78%	69-86	76/98	82%	74-89	80/98
Accuracy	92%	87-96	141/154	74%	66-81	90/122	92%	87-96	141/154	70%	63-77	108/154	79%	72-85	121/154
Subgroup only considering pancreatic carcinoma as a malignancy
Sensitivity	93%	86-100	51/55	26%	14-38	13/50	93%	86-100	51/55	87%	78-96	48/55	65%	53-78	36/55
Specificity	89%	83-95	87/98	100%	NA	67/67	89%	83-95	87/98	78%	69-86	76/98	82%	74-89	80/98
Accuracy	90%	85-95	138/153	68%	60-77	80/117	90%	85-95	138/153	81%	75-87	124/153	76%	69-78	116/153
Subgroup only considering ampullary carcinoma as a malignancy
Sensitivity	84%	68-100	16/19	53%	29-77	9/8	95%	85-100	18/19	68%	48-89	13/19	47%	25-70	9/19
Specificity	89%	83-95	87/98	100%	NA	67/67	89%	83-95	87/98	78%	69-86	76/98	82%	74-89	80/98
Accuracy	88%	82-94	103/117	90%	84-97	76/84	90%	84-95	105/117	76%	68-84	89/117	76%	68-84	89/117

IDUS: Intraductal ultrasound; ETP: Endoscopic transpapillary biopsies; EUS: Endoscopic ultrasound; CT: Computed tomography; NA: Not available.

Table 3 Method-dependent accuracy rates and tests of significance (proximal vs distal stenosis) with respect to the localization of bile duct stenosis n (%)

Method	Stenosis (localization)	Accuracy	95%CI	P value
				(prox. vs distal)
IDUS	Proximal	28 (100)	100-100	0.419
	Distal	165 (89)	85-94
ETP	Proximal	13 (46)	28-65	0.275
	Distal	93 (62)	55-70
IDUS + ETP	Proximal	28 (100)	100-100	0.505
	Distal	167 (90)	86-95
EUS	Proximal	16 (57)	39-75	< 0.0001
	Distal	147 (79)	74-85
CT	Proximal	25 (89)	79-100	0.09
	Distal	132 (71)	65-78

IDUS: Intraductal ultrasound; ETP: Endoscopic transpapillary biopsies; EUS: Endoscopic ultrasound; CT: Computed tomography.