LOCALIZING THE LESION BY CAPSULE ENDOSCOPY

Abstract

Purpose: One of the challenges in improving the quality of information obtained by capsule endoscopy is accurate localization of an abnormality. The present study highlights techniques that help in accurate localization of small bowel lesions and the role this plays in patient management. Methods: The present study employed localization software and capsule transit times from fixed anatomical landmarks in determining the location of abnormal lesions. An antenna array was applied in a predefined pattern to the abdomen. The antenna picks up radio-frequency signals from the capsule endoscope; the sensors closest to the M2A™ capsule (Given Imaging) receive the strongest signal. Three sensors with the strongest signals were used to triangulate the position of the capsule over the abdominal wall (in one of four quadrants). This information together with knowledge of how far the capsule traveled in time since passing a landmark such as the pylorus was used to determine the location of the lesion. Results: Case 1: A 72 year old lady with 7-month history of intermittent malena, required transfusions every 6–8 weeks. Multiple upper and lower en-doscopic examinations including enteroscopy (Pantex VSB 2900) and small bowel enteroclysis were negative. Capsule endoscopy revealed blood in the distal ileum about 3 hours from the pylorus and 37 minutes from the ileoce-cal valve. Localization software put the lesion in the left lower quadrant just left of midline. At laparotomy, an enteroscopy performed through an entero-tomy in the distal ileum quickly located a bleeding AVM. Case 2: A 68 yr old was referred for occult GI bleeding and anemia. Upper endoscopy, enteroscopy, colonoscopy and small bowel barium study were normal. Capsule endoscopy revealed a small tumor 7 minutes from the pylorus. Localization software put it in the right upper quadrant. At repeat endoscopy with a pedi-atric colonoscope, an ulcerated mass was identified and successfully resected surgically. Conclusions: The localization software is useful adjunct in determining the site of a lesion in the small intestine. Lesions in the right upper and sometimes right lower quadrants can be reached by enteroscopes. The time elapsed afterthe capsule crossesthe pylorus is areliable indicator of whether a lesion can be reached by an endoscope. We believe that lesions within 30 minutes of the pylorus may be reached at enteroscopy. Further developments in the software technology are likely to improve the accuracy for localizing lesions seen by capsule endoscopy.