Linear endoscopic ultrasound of the liver: a practical, landmark-based approach to segmental orientation

Linear endoscopic ultrasound (EUS) has emerged as an essential tool in endohepatology, enabling high-resolution evaluation of the hepatic parenchyma, vascular structures, and segmental anatomy of the liver via transgastric and transduodenal imaging. As the role of linear EUS has expanded to include tissue acquisition, biliary drainage, portal pressure measurement, and targeted hepatic interventions, a thorough understanding of the liver anatomy has become indispensable to ensure procedural safety and efficacy. However, EUS-based liver evaluation remains technically challenging because of its use of dynamic imaging planes and the absence of fixed anatomical reference points. This review proposes a structured, station-based approach that integrates Couinaud's segmental anatomy with reproducible vascular and ligamentous landmarks. By correlating the transgastric and transduodenal imaging views with the corresponding portal venous, hepatic venous, and ligamentous axes, this framework provides a systematic method for accurate segmental identification. Adoption of this approach may enhance diagnostic accuracy, facilitate safe therapeutic interventions, and promote more structured and reproducible training frameworks.