Gastrointestinal Angiodysplasia: CT Findings

Transcription

1 Gastrointestinal Angiodysplasia: CT Findings Poster No.: C-1792 Congress: ECR 2012 Type: Authors: Keywords: DOI: Educational Exhibit G. Anguita Martinez, A. Fernandez Alfonso, D. C. Olivares Morello, J. Gonzalez Nieto, P. Rodriguez Carnero, C. García Villafañe; Madrid/ES Dysplasias, Education, CT-Angiography, CT, Gastrointestinal tract, Emergency /ecr2012/C-1792 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 7

2 Learning objectives To review the main computed tomography (CT) findings of gastrointestinal angiodysplasia. Background Gastrointestinal angiodysplasia is the most common vascular lesion of the gastrointestinal tract; the second most important cause of haemorrhage in the lower intestinal tract, as well as the main cause of recurrent bleeding, particularly in old patients. Its etiopathogenesis is not well understood although it is supposed to have its origin in degenerative lesions which occurs secondary to intermittent obstruction of submucosal small veins during muscular contraction and cecum distension. Seventy-seven percent of angiodysplasias are located in the cecum and ascending colon, 15% are located in the jejunum and ileum, and the remainder is distributed throughout the alimentary tract. Clinical presentation in patients with angiodysplasia is usually characterized by marooncolored stool, melena, or hematochezia. Bleeding is usually low grade, but it can be massive in approximately 15% of patients. In 20-25% of bleeding episodes, only tarry stools are passed. Iron deficiency anemia and stools that are intermittently positive for occult blood can be the only manifestations of angiodysplasia in 10-15% of patients. Bleeding stops spontaneously in greater than 90% of cases but is often recurrent. Frequently the diagnosis is made with colonoscopy and arteriography, however, helical CT has become a very efficient diagnostic tool in these situations. Imaging findings OR Procedure details MDCT scanning protocol An unenhanced CT scan is obtained immediately prior to CT angiography to identify any preexisting hyperattenuating areas within the bowel lumen that could be confused with hemorrhage at CT angiography. The technical parameters used Page 2 of 7

3 to acquire the unenhanced data are as follows: detector configuration, 64 x mm; section thickness, 1 mm; section increment, 1mm. 120kV; 150 ma; pitch, 1,2; and rotation time, 0.8 seconds Contiguous 3-mm axial and coronal sections are then reconstructed and transferred to the picture archivingand communication system review, with the CT angiographic data for review. CT Angiographic Protocol for Detection of Gastrointestinal Bleeding. detector configuration, 64 x mm; section thickness,0.9 mm; section increment, mm. 120 kv; 405 ma; pitch, 1,2; and rotation time, 0,8 seconds. 100ml of intravenous contrast material, 4 ml/sec, typically via an antecubital vein. Automatic bolus-triggering software with use of a circular region of interest is placed on the abdominal aorta at the level of the diaphragm with a trigger threshold of 25 HU. Data acquisitioncommences 25 seconds after the bolustrigger threshold is reached. scanning is performed from the xyphoid process through the symphysis of pubis. The acquired data are thenreconstructed into 1,25 mm axial sections with a section increment of 1 mm for workstation review and contiguous 3-mm axial and coronal sections for picture archivingand communication system review. In our experience, the additional time delay provided by scanning during the late capillary phase may also increase the sensitivity of CT angiography, allowing detection of slower bleeding rates that may not be evident at arterial phase scanning. The CT angiographic diagnosis of active GI bleeding is made when hyperattenuating extravasated contrast material not present at unenhanced CT is seen within the bowel lumen ( Fig. 1). The main findings of Angiodysplasia Gastrintestinal we can find in CT angiography include a group of hypertrophied vessels in the colonic wall, early filling veins as well as a supplying enlarged artery (Fig. 2,3). Page 3 of 7

4 Images for this section: Fig. 1: Active descending colon bleeding. Axial unenhanced CT scan (left imaging) and axial CT angiogram (right)demonstrate active contrast material extravasation into the descending colon. Page 4 of 7

5 Fig. 3: Signs of ileum Angiodysplasia. CT angiogram shows early filling of ileocolic and superior mesenteric veins and hypertrophied of the antimesenteric ileum veins. Also we can observe active bleeding into ileum lumen. Fig. 2: Signs of descending colon angiodysplasia. CT angiograms shows early filling of inferior mesenteric vein and hypertrophied antimesenteric veins of the wall of the descending colon. Page 5 of 7

6 Conclusion Colonic angiodysplasia is the second most important cause of haemorrhage in the lower gastrointestinal tract. Most common diagnostic tools for this condition are colonoscopy and mesenteric arteriography., although everal studies have been performed trying to assess the usefulness of helical CT.Their study demonstrated an overall locationbased sensitivity, specificity and positive predictive value for CT angiography in the detection and localization of colonic angiodysplasia of 70%, 100%, and 100% respectively. Personal Information References 1.Christopher J. Laing, MD, Terrence Tobias, MD # David I. Rosenblum,DO, Wade L. Banker, MD, Lee Tseng, MD, Stephen W. Tamarkin,MD.Acute GastrointestinalBleeding: Emerging Role of MultidetectorCT Angiography and Review of Current Imaging Techniques.Radiographics July-August : Bruno M. Graça, MD, Paulo A. Freire, MD, Jorge B. Brito, MD José M. Ilharco, MD, Vitor M. Carvalheiro, MD, Filipe Caseiro-Alves, MD, PhD. Gastroenterologic and Radiologic Approach to Obscure Gastrointestinal Bleeding: How, Why, and When?.Radiographics January : Fallah MA, Prakash C, Edmundowicz S. Acute gastrointestinal bleeding. Med Clin North Am 2000;84(5): Page 6 of 7

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