Pancreaticobiliary direct imaging and novel therapies

Known or suspected pathology within the pancreaticobiliary system is a common clinical problem which can often be assessed with data such as history, physical examination, and laboratory tests. Noninvasive or indirect imaging techniques, such as ultrasound, computed tomography, and magnetic resonance cholangiopancreatography are widely available and can provide useful information in the evaluation of pancreaticobiliary pathology. The gold standard for direct imaging and evaluation of the pancreaticobiliary tree is endoscopic retrograde cholangiopancreatography. This technique not only allows for diagnostic imaging with injection of contrast dye into the biliary and pancreatic ducts but also allows for therapeutic interventions such as stone extraction, dilation, stent placement, and tissue sampling. Endoscopic ultrasound (EUS) is another commonly used direct imaging modality which allows for more precise images and directed therapy such as aspiration or ablation. EUS is considered to be one of the most sensitive tests for staging malignancy and detecting a wide range of pancreaticobiliary illnesses, and has also been shown to be useful in evaluation of indeterminate biliary strictures. Despite the accuracy and widespread use of these modalities, there are limitations to their diagnostic and therapeutic utility. For this reason, novel imaging and therapy techniques have been and continue to be developed. Although some of these modalities have been used for many years, recent advances in technology have enabled these modalities to have greater clinical utility, as well as allowing endoscopists more experience. This article focuses on these “novel” techniques, including direct pancreaticobiliary imaging with cholangioscopy and pancreatoscopy, and probe-based technologies such as intraductal ultrasonography, probe-based confocal laser endomicroscopy, and optical coherence tomography. Endoscopic ablative techniques such as radiofrequency ablation and intraductal argon plasma coagulation as well as stent and lithotripsy technologies would be described as they pertain to the pancreaticobiliary tree. Briefly discussed would be fiber-optic scopes through an fine needle aspiration to directly image cystic lesions, as well as novel guidewire and EUS-based technologies.