Diagnostic performance of digital and video cholangioscopes in patients with suspected malignant biliary strictures: a systematic review and meta-analysis

Abstract

Background: Per-oral cholangioscopy (POC) has evolved over the past decade from fiberoptic to digital and video imaging systems. Nowadays, only direct per-oral cholangioscopy (DPOC) and digital single-operator cholangioscopy (DS) are performed in daily practice. With better image resolution, POC is increasingly used as diagnostic tools in patients with suspected malignant biliary stricture (MBS). We aimed to evaluate the diagnostic yield of digital/video cholangioscopes for the diagnosis of MBS.

Methods: A systematic search was performed in MEDLINE, Embase, and ISI Web of Knowledge databases until April 2020, to identify randomized controlled trials and prospective studies using digital or video POC. The meta-analysis of diagnostic accuracy study was performed to calculate summary estimates of the primary outcomes, including pooled sensitivity, and specificity of POC to diagnose MBS using bivariate random-effects models. Tissue histopathology was used as the reference standard for MBS diagnosis. For benign stricture, negative tissue histopathology and at least 6 months clinical follow-up were required.

Results: Thirteen original articles with 876 patients were identified. The overall pooled sensitivity and specificity were 88 (95% CI 83-91) and 95 (95% CI 89-98), respectively. The area under the curve (AUROC) was 0.94 (95% CI 0.92-0.96). Subgroup analysis showed that cholangioscopic image impression provided significantly higher sensitivity (93% (95% CI 88-96) vs 82% (95% CI 76-87); p = 0.007), but lower specificity 86% (95% CI 75-92) vs 98 (95% CI 95-99); p < 0.001) than the tissue diagnosis from cholangioscopic-guided biopsy. In addition, biopsy obtained from DPOC had significantly higher sensitivity than that of DS (92% (95% CI 81-97) vs 79% (95% CI 72-84); p = 0.004). Diagnostic performance under image-enhanced endoscopy was not significantly better from white light endoscopy.

Conclusions: Digital/video POC has very high diagnostic performance to diagnose MBS. While image diagnosis provides higher sensitivity than biopsy, its specificity drops as a trade-off.

Keywords: Biliary stricture; Cholangiocarcinoma; Cholangioscopy; ERCP.