High-definition confocal endomicroscopy of the common bile duct

Probe-based confocal laser endomicroscopy (pCLE) of the common bile duct (CBD) is a new procedure that can be used for assessing indeterminate billiary strictures. The CBD has been examined using the CholangioFlex miniprobe (Mauna Kea Technologies, Paris, France), which has a lateral resolution of 3.5 microm and diameter of <1.0 mm. However, larger-diameter higher-resolution confocal probes are available. We aimed to determine if pCLE of the CBD with the high-definition GastroFlex(UHD) miniprobe (UHDp) was feasible. This probe has a lateral resolution of 1 microm and an outer diameter of 2.6 mm.

Eleven consecutive patients undergoing endoscopic retrograde cholangiopancreatography for various indications at a single, large, academic center were included in the study. Examination of the CBD was attempted with the UHDp after injection of 2.5 mL of 10% fluorescein. A 0.035 inch guidewire was first placed into the CBD and the confocal probe was subsequently inserted adjacent to the guidewire. Position of the miniprobe was identified fluoroscopically.

The GastroFlex(UHD) miniprobe was successfully introduced into the CBD in 10 of 11 patients. Cellular structures and individual cell morphology seemed to be more clearly visualized with the UHDp compared with the CholangioFlex probe. No significant side effects except 1 case of mild pancreatitis.

We demonstrate that high-definition pCLE of the CBD by the GastroFlex(UHD) miniprobe is feasible and may offer improved image quality over the standard CholangioFlex probe. Further studies are needed to see if this improves the diagnostic accuracy of bile duct lesions.