[Navigation surgery in the biliary surgery and NOTES: carbon dioxide enhanced MDCT cholangiopancreatography and image overlay surgery].

The preoperative image diagnosis in the biliary disease devolved from analog imaging such as PTCD or ERCP to digital data analysis such as MDCT, MRI, DIC-CT, or MRCP. In late years synchronous visualization of the biliary tracts and associated blood vessels was enabled in fusion method or MRCPA. Carbon dioxide enhanced MDCT cholangiopancreatography depicts the biliary and pancreatic duct by the negative contrasting effect of the carbon dioxide, and is ideal for the surgical navigation. Real time correspondence to the operator's demand is important, and multidirectional observation and volume rendering method are effective for the use of it during surgery. The introduction of image analysis software OsiriX improves complexity and image construction time, and it may be practical. Image overlay surgery consisted of augmented reality and mixed reality is developing toward practical use in navigated surgery. In recent years, NOTES (Natural Orifice Translumenal Endoscopic Surgery) was developed, the support system of the navigation of such flexible endoscope is desired earnestly.