Intraductal ultrasound substantiates diagnostics of bile duct strictures of uncertain etiology

Table 1 Baseline characteristics of the patient cohort

Baseline characteristics
Patients (n)	397
Age (yr), mean ± SE	61.43 ± 13
Sex (M/F)	210/187
IDUS performed (n)	397
Follow-up (mo), mean ± SE	39.7 ± 23.1
Follow-up range (mo)	12-100
Procedures (n)
Clinical follow-up	95
Surgery	264
Palliative therapy	32
Calculus extraction	6
Localization of stricture (CBD)
Proximal third	59
Middle third	46
Distal third	292
Final diagnosis (n)
Normal bile duct	25
Benign disease
Papillitis	30
Ampullary adenoma	18
Cholangitis	17
PSC	8
Mirizzi syndrome	7
Choledocholithiasis	14
Pancreatitis	59
Pseudocyst	4
Portal vein thrombosis	1
Papilloma of pancreatic duct	3
Choledochal cyst	1
Postoperative stenosis	1
Pancreatic cystadenoma	2
Caroli’s syndrome	1
Malignant disease
Cholangiocarcinoma	85
Pancreatic carcinoma	80
Ampullary carcinoma	26
Gallbladder carcinoma	9
Hepatocellular carcinoma	6

CBD: Common bile duct; PSC: Primary sclerosing cholangitis; M: Man; F: Female; IDUS: Intraductal ultrasound.

Table 2 Staging results of intraductal ultrasound (n = 397)

	Final diagnosis according to histopathology or long-term follow-up
Method, classification	Benign lesion	Carcinoma	CCC	Pancreatic CA	Ampullar CA	GB CA	HCC
IDUS, benign	171	14	2	5	5	1	1
IDUS, malignant	20	192	83	75	21	8	5

CA: Carcinoma; GB CA: Gallbladder cancer; CCC: Cholangiocellular carcinoma; HCC: Hepatocellular carcinoma; IDUS: Intraductal ultrasound.

Table 3 Sensitivity, specificity and accuracy rates of intraductal ultrasound (n = 397)

Tumor	Sensitivity (95%CI)	Specificity (95%CI)	Accuracy (95%CI)
All tumors	0.93 (0.90-0.97)	0.89 (0.85-0.94)	0.91 (0.89-0.94)
CCC	0.98 (0.94-1.0)	0.98 (0.94-1.0)	0.92 (0.89-0.95)
Pancreatic CA	0.94 (0.88-0.99)	0.90 (0.85-0.94)	0.91 (0.87-0.94)
Ampullary CA	0.81 (0.66-0.96)	0.90 (0.85-0.94)	0.89 (0.84-0.93)
GB CA	0.89 (0.68-1.0)	0.90 (0.85-0.94)	0.90 (0.85-0.94)
HCC	0.83 (0.54-1.0)	0.90 (0.85-0.94)	0.89 (0.85-0.94)

CA: Carcinoma; GB CA: Gallbladder cancer; CCC: Cholangiocellular carcinoma; HCC: Hepatocellular carcinoma; IDUS: Intraductal ultrasound.

Table 4 Statistical analysis of intraductal ultrasound accuracy rates relating to localization of bile duct strictures (n = 397)

Localization of stenosis	N	Accuracy (95%CI)	Test for significance	P value
Proximal third	55/59	0.93 (0.87-1.0)	Proximal vs middle third	0.958
Middle third	43/46	0.93 (0.87-1.0)	Proximal vs distal third	0.280
Distal third	260/292	0.89 (0.85-0.93)	Middle vs distal third	0.308

Table 5 Histopathological vs intraductal ultrasound T staging

	Histopathology
IDUS	pT1	pT2	pT3/4	∑
uT1	12	9	13	34
uT2	1	26	24	51
uT3	1	5	56	62
∑	14	40	93	147
Sensitivity (95%CI)	0.86 (0.67-1.0)	0.65 (0.50-0.80)	0.60 (0.50-0.70)
Specificity (95%CI)	0.83 (0.77-0.90)	0.77 (0.69-0.85)	0.89 (0.81-0.97)
Accuracy (95%CI)	0.84 (0.78-0.89)	0.73 (0.66-0.81)	0.71 (0.63-0.78)

IDUS: Intraductal ultrasound.

Table 6 N staging accuracy-histopathology vs intraductal ultrasound

	Histopathology
IDUS	pN0	pN1	∑
uN0	44	23	67
uN1	23	57	80
∑	67	80	147
Sensitivity (95%CI)	0.66 (0.61-0.81)	0.61 (0.57-0.79)
Specificity (95%CI)	0.61 (0.54-0.77)	0.66 (0.54-0.77)
Accuracy (95%CI)	0.69 (0.61-0.76)	0.69 (0.61-0.76)

IDUS: Intraductal ultrasound.

Table 7 Meta-analysis of intraductal ultrasound accuracy in detecting bile duct malignancy

Study	No. of patients	Accuracy of IDUS
Menzel et al[15]	57	89%
Tamada et al[30]	19	84%
Domagk et al[14]	60	88%
Domagk et al[31]	33	88%
Domagk et al[29]	30	95%

IDUS: Intraductal ultrasound.