How Endoscopic Guidance Augments Nonvascular Image-guided Interventions.

Endoscopy can improve guidance in nonvascular procedures performed by interventional radiologists (IRs). Historically, the major limiting factors preventing the widespread use of endoscopic tools by IRs were the large diameter (>20F) and length of the endoscopes. IRs had to significantly upsize their access into vascular organs such as the kidney and liver to allow endoscope placement. With the advent of newer endoscopes with sizes smaller than 11F (approximately 4 mm in diameter), percutaneous endoscopy has become more feasible than before. IRs routinely place percutaneous drains (eg, abscess drains, biliary drains, percutaneous nephrostomies, and percutaneous cholecystostomies). Once the drain is in position and the acute infection (if present) has resolved, the IR can use the percutaneous access to perform image-guided and endoscopically guided procedures, depending on the clinical situation. Most percutaneous image- and endoscopically guided interventions performed by IRs involve procedures for biliary and gallbladder pathologic conditions. Image-guided procedures with additional endoscopic guidance can also be used to manage urinary, gastrointestinal, and gynecologic pathologic conditions. The authors review the current applications and techniques of percutaneous endoscopy in interventional radiology. In unique situations, IRs can also perform endoscopy through natural orifices (eg, the urethra) or surgically created orifices (eg, urostomies). The authors also discuss the adjunctive techniques that are enhanced or made possible because of endoscopy in interventional radiology, including but not limited to endoscopic forceps biopsies, endobiliary ablation, laser stricturotomy, lithotripsy, and stone extraction. An invited commentary by Srinivasa is available online. Online supplemental material is available for this article. © RSNA, 2022.