Single-operator Digital Cholangioscopy for the Diagnosis of Malignant and Benign Biliary Strictures
Single-operator Digital Cholangioscopy for the Diagnosis of Malignant and Benign Biliary Strictures
Differentiation between malignant and benign biliary strictures can be challenging. Accurate
 differentiation of malignant biliary strictures from benign ones is crucial to guide
 management decisions.

 While conventional tissue acquisition techniques such as brush cytology or intraductal biopsy
 of the biliary stricture is often performed during ERCP for tissue diagnosis, their
 sensitivities are suboptimal. The average sensitivities for brush cytology and intraductal
 biopsy were reported to be ~ 59% and ~ 63% respectively.

 When the cause of a biliary stricture remains unclear despite conventional ERCP techniques
 for diagnosis, cholangioscopy is often performed during ERCP to clarify the diagnosis. This
 allows an endoscopist to obtain a visual impression (VI) and to perform targeted biopsy under
 direct visualization of the biliary stricture.

 Recently, a digital SOC system (SpyGlass Digital System (SpyGlass DS), Boston Scientific,
 USA) has become available and has the potential to further improve the diagnosis of malignant
 and benign biliary strictures. The utility of this digital SOC in the evaluation of biliary
 strictures has not been well studied. We propose this study to evaluate the utility of the
 digital SOC during ERCP in the diagnosis of malignant and benign biliary strictures.
Differentiation between malignant and benign biliary strictures can be challenging. Accurate
 differentiation of malignant biliary strictures from benign ones is crucial to guide
 management decisions. While a mass lesion involving the bile duct may be observed on imaging
 such as ultrasound (USG), computed tomography (CT), or magnetic resonance imaging (MRI) in
 patient presenting with obstructive jaundice, early malignancy of the bile duct may often
 present with a ductal stricture without an obvious mass on imaging. Diagnosis of early stage
 malignancy of the bile duct is desirable since the lesion may be amenable to surgical
 resection of curative intent.

 Endoscopic retrograde cholangiopancreatography (ERCP) is an important diagnostic and
 therapeutic endoscopic technique in patients with obstructive jaundice and a suspected
 biliary stricture. While conventional tissue acquisition techniques such as brush cytology or
 intraductal biopsy of the biliary stricture is often performed during ERCP for tissue
 diagnosis, their sensitivities are suboptimal. The average sensitivities for brush cytology
 and intraductal biopsy were reported to be ~ 59% and ~ 63% respectively.

 When the cause of a biliary stricture remains unclear despite conventional ERCP techniques
 for diagnosis, cholangioscopy is often performed during ERCP to clarify the diagnosis.
 Cholangioscopy performed during ERCP involves passing a small scope (~ 10 French in size)
 through the working channel of the ERCP duodenoscope for direct visualization of the bile
 duct mucosa. This allows an endoscopist to obtain a visual impression (VI) and to perform
 targeted biopsy under direct visualization of the biliary stricture. The VI of a malignant
 biliary stricture is often characterized by the presence of intraductal abnormal tissue
 growth, and dilated, irregular, tortuous tumor vessels. During standard ERCP, cholangioscopy
 can be performed using a 2-operator "mother-baby" system, or a single-operator system. While
 the 2-operator "mother-baby" cholangioscopy technique can provide good image quality of the
 biliary stricture during ERCP, its use has been limited due to the cumbersome nature of the
 procedure requiring 2 endoscopists and the relative fragility of the video cholangioscope.
 Single-operator cholangioscopy (SOC) system, such as the SpyGlass Direct Visualization
 System, on the other hand allows a single operator to perform cholangioscopy during ERCP. In
 a recent meta-analysis of the studies using the optical fiber based SOC in the evaluation of
 indeterminate biliary strictures, the combined sensitivity and specificity of VI were 90% and
 87% respectively, and the combined sensitivity and specificity of cholangioscopy directed
 biopsy were 69% and 98% respectively. The overall incidence of procedure-related adverse
 event (eg, infection, perforation, pancreatitis, etc) was reported to be 7.5% for diagnostic
 SOC during ERCP.

 Despite the promising results of VI using the optical fiber based SOC from prior studies, the
 actual image quality in daily clinical practice is frequently regarded as fair only due to
 the use of a small optical fiber for imaging, and gradual loss of resolution over time from
 optical fiber damage. A SOC with better image quality is needed for better endoscopic
 diagnosis of a biliary stricture.

 Recently, a digital SOC system (SpyGlass Digital System (SpyGlass DS), Boston Scientific,
 USA) has become available and has the potential to further improve the diagnosis of malignant
 and benign biliary strictures. The utility of this digital SOC in the evaluation of biliary
 strictures has not been well studied. We propose this study to evaluate the utility of the
 digital SOC during ERCP in the diagnosis of malignant and benign biliary strictures.
Inclusion Criteria:

 -  Age ≥ 18 years

 -  Patients presenting with obstructive jaundice with clinical suspicion for a biliary
 stricture based on imaging findings or during ERCP

 -  Written informed consent available

 Exclusion Criteria:

 -  Contraindications for endoscopy due to comorbidities

 -  Unable to provide written informed consent

 -  Patients with clinical evidence of ongoing cholangitis precluding a safe
 cholangioscopy procedure

 -  Pregnant patients

 -  Moribund patients from terminal illnesses