Abstract
The challenge of effectively eliminating air during gastrointestinal endoscopy using ultrasound techniques is apparent. This difficulty arises from the intricacies of removing concealed air within the folds of the gastrointestinal tract, resulting in artifacts and compromised visualization. In addition, the overlap of folds with lesions can obscure their depth and size, presenting challenges for an accurate assessment. Conversely, in intricately folded regions of the gastrointestinal tract, such as the stomach, intestine, and colon, insufficient delivery of air or CO(2) into the cavity impedes luminal expansion, hindering the accurate visualization of lesions concealed within the folds. Although this underscores the requirement for substantial airflow, excessive airflow can hinder visualization of bleeding lesions and other abnormalities. Considering these challenges, an ideal endoscopic device would facilitate the observation of lesions without the requirement for air or CO(2) delivery whereas, ensuring optimal expansion of the gastrointestinal tract. Recently, transparent gels with specific viscosities have been employed more frequently to address this issue. This review aims to elucidate how these gels address these challenges and provide a solution for enhanced endoscopic visualization.