Novel ultrasound capsule endoscopy for gastrointestinal scanning: An in vivo animal study.

Background and objectives: EUS is an important modality for diagnosis and assessment of gastrointestinal (GI) subepithelial lesions. However, EUS is invasive and operator-dependent and requires sedation in most cases. The newly developed ultrasound capsule endoscopy (USCE) system, with both white-light and ultrasound imaging modalities, is a minimally invasive method for superficial and submucosal imaging of the esophagus. This animal study aimed to evaluate the feasibility and efficacy of the USCE system for upper GI tract and small bowel scanning.

Methods: Three Bama miniature pigs were selected to scan their esophagus, stomach, small bowel, and simulated submucosal lesions. USCE was performed first, followed by EUS. The feasibility of USCE was measured by obtaining ultrasound images of normal GI walls and submucosal lesions under the guidance of optical viewing. The efficacy of USCE was evaluated by comparing tissue structures and lesion features shown on ultrasound images obtained with both instruments.

Results: Under the optical mode of USCE, the GI tract was well visualized, and all simulated lesions were located. Clear ultrasound images of normal GI tract and submucosal lesions were acquired. Ultrasound images of the esophagus, stomach, and small bowel were characterized by differentiated multilayer structures on USCE, which was consistent with the structures displayed on EUS. And the visualization of submucosal lesions, using both USCE and EUS, was characterized by a hypoechoic and well-demarcated mass in the layer of submucosa.

Conclusions: This animal study indicated the feasibility and potential clinical efficacy of this USCE for simultaneous optical mucosal visualization and transmural ultrasound imaging of upper GI tract and small bowel, providing possibility of using this technology for a wider range of GI tract.