遠藤 和洋

BACKGROUND: There are no studies to date using air as an enteral contrast medium for small bowel expansion in virtual enteroscopy. We examine the feasibility of air as an enteral contrast medium for virtual enteroscopy to achieve small bowel expansion. PATIENTS AND METHODS: Two volunteers and six patients were examined. The six patients included three with small bowel tumors, one with small bowel hemorrhage and two with suspected cases of post-operative small bowel stenosis. A duodenal tube was inserted under fluoroscopy and approximately 2000 ml air was administered prior to scanning. A 16-detector row computed tomography apparatus was used with 2-mm thick slices. Intravenous contrast material was administered to the patients, but not to the volunteers. Computed tomography scanning was performed two to three times until the air reached the colon. Two examiners reconstructed multi-planar reformation, volume rendering and virtual endoscopy. These images were compared with double balloon enteroscopic findings and/or resected specimens. RESULTS: There were no complications associated with this examination. In the volunteers the difference between the circular folds of the jejunum and those of the ileum was clearly visualized on virtual endoscopy. Angiodysplasia (9 mm), gastrointestinal stromal tumor (15 mm) and arteriovenous malformation were clearly detected by virtual endoscopy. In contrast, one tumor could not be detected because of inadequate intestinal distension. In the two suspected cases of the stenosis, the lesion was not identified because stenotic lesions were not differentiated from normal peristalsis of the small bowel. CONCLUSIONS: Air is a feasible enteral contrast material for virtual enteroscopy.

BACKGROUND: In natural orifice transluminal endoscopic surgery (NOTES), the endoscope has the disadvantages of an unstable visual field and wide blind space. We developed a compact charge-coupled device (CCD) camera unit that can be transgastrointestinally placed in the abdominal cavity. METHODS: The requisites for a wireless CCD camera unit for use in NOTES have been cited as: monitoring performance, fixation to the abdominal wall, attitude control, and antifogging functionality. Models to meet these requisites were prepared to assess their performance. The monitor had a CCD with dimensions of 7 x 7 x 7 mm and resolution of 410,000 pixels. The unit had a structure that allowed its attachment to the endoscope apex when placed to the abdominal wall. The abdominal wall fixation unit was equipped with a pantograph-type needle structure that was easily activated and retained by changing the polarity of an electromagnetic force. The pantograph-type needle head was designed to rotate by 360 degrees as an attitude-control mechanism, and both the pantograph and attitude-control mechanisms enabled attitude control in horizontal and vertical directions by a magnetic force applied from outside the body. Fogging was prevented by a vibration mechanism that physically cleaned the CCD lens surface and by titanium dioxide coating of the lens surface. RESULTS: The CCD camera unit was confirmed to have sufficient performance as an auxiliary monitor for endoscopy in terms of visual field and resolution. The pantograph-type needle structure successfully completed fixation of the CCD camera unit to the abdominal wall. Unit attitude was easily controlled, and fogging could be addressed by water supply before insertion of the CCD camera unit into the peritoneal cavity. CONCLUSIONS: The wireless CCD camera unit was verified to function as an effective second eye in NOTES by using the described mechanisms and antifogging coating.

CONTEXT: Although rare, a pancreatic arteriovenous malformation can have serious consequences. A diagnosis of arteriovenous malformation requires evidence of aberrant communication between the arterial and the venous systems. This report describes a case where the use of multi-detector row CT and specific post-processing methods provided a diagnosis of arteriovenous malformation. This minimally invasive diagnostic approach resulted in a clear, precise and comprehensive visual representation of the pancreatic arteriovenous malformation. CASE REPORT: A 60-year-old man with right hypochondriac pain presented with a mass in the head of the pancreas. The hypochondriac pain resolved spontaneously and physical examination revealed no abnormal findings. A multi-detector row CT study was performed. The data obtained in the arterial phase demonstrated a high-contrast mass in the head of the pancreas and early enhancement of the portal vein. A maximum intensity projection method clarified the aberrant vascular communication. Changes in Hounsfield numbers were observed using a multi-planar reformation method. A volume-rendering method was used to create a 3D model which demonstrated the spatial relationship between the aberrant vascular communication and the surrounding tissue. An annual follow-up study using this technique showed no significant alteration. CONCLUSIONS: Multi-detector row CT with specific post-processing methods is a useful diagnostic tool for pancreatic arteriovenous malformation.

BACKGROUND/PURPOSE: We tried to determine whether the customization of an X-TRACT Tissue Morcellator could avoid the laceration-induced distension of surgical incisions/openings when transintestinally removing resected liver tissue from the body, when the greatest dimension of the tissue exceeded the dimension of the opening. METHODS: Pigs were used to examine changes in the caliber and shape of surgical incisions made with a conventional hook knife and insulation-tipped diathermic (IT) knife for electrodissection in endoscopy, and to examine changes in circular incision made with a customized X-TRACT Tissue Morcellator. The ENDO CATCH II device was used to remove tissue. RESULTS: Laceration occurred in the "roundness-lost portion" of the surgical incisions made with the hook knife, thus confirming the greatest dimension of the distended incisions and the occurrence of an irregular laceration. In the circular incision that were made with the customized X-TRACT Tissue Morcellator, by contrast, the removal of resected liver tissue whose greatest dimension was fivefold greater than that of the surgical openings did not increase the caliber of the openings. The shape of the openings remained round, and no laceration was observed. CONCLUSIONS: The use of the customized X-TRACT Tissue Morcellator with an electrifiable round cutter allowed the performance of transintestinal hepatectomy and the removal of a solid organ through surgical openings that had been made in the gastrointestinal wall.