The role of imaging in gastrointestinal bleed

The Role of Imaging in Gastrointestinal Bleeding Introduction Common causes of GI bleeding ● Upper gastrointestinal bleeding ● Lower gastrointestinal bleeding ○ ○ ○ ○ ○ esophageal, gastric and duodenal ulcers esophagitis, gastritis, duodenitis, pancreatitis neoplasms vascular malformations varices ○ ○ ○ ○ ○ ○ diverticulosis post-polypectomy bleeding ischemic colitis colorectal polyps/neoplasms inflammatory bowel disease anorectal conditions ● Small bowel bleeding ○ ○ ○ ○ ○ neoplasia meckel’s diverticulum polyposis syndromes Angioectasia NSAID ulcers Nomenclature ● ● ● ● Upper GI bleeding (UGIB): bleeding originating proximal to the Treitz ligament Lower GI bleeding (LGIB): bleeding originating from the colon or rectum Suspected small-bowel bleeding: the upper and lower GI tracts have been evaluated (typically with endoscopy) and no bleeding site has been identified Obscure GI bleeding: no bleeding source is found after the entire GI tract has been examined with advanced techniques Radiologic imaging modalities of choice Radiologic imaging modalities ● ● ● ● Technetium 99m scintigraphy Computed tomography angiography (CTA), Multiphase computed tomography enterography (CTE) Catheter angiography (CA) Scintigraphy ● Protocol ○ ○ ○ labeling the RBCs intravascular injection dynamic acquisition ● Advantage ● Disadvantages ○ ○ ○ ○ Non-invasive Detect slowest bleed No bowel preparation required Can detect intermittent bleed ○ ○ ○ Ionizing radiation and radiation dose Non-therapeut Not good for UGIB Multiphase computed tomography enterography (CTE) ● Advantages ● Disadvantages ○ ○ ○ detect source in obscure bleed detect bowel pathologies even when not actively bleeding evaluate bowel wall and abdominal vessels simultaneously ○ ○ ○ ○ not good for acutely bleeding unstable patients requires proper technique and good bowel distention non-therapeutic ionizating radiation Multiphase computed tomography enterography (CTE) ● Recommendation ○ ○ initial diagnostic modality for LGI small bowel bleed with pre-existing bowel pathology In patients with negative capsule endoscopy to look for small or large bowel source Catheter angiography (CA) ● Protocols ○ selective arterial catheterization Catheter angiography (CA) ● Advantages ● Disadvantages ○ ○ ○ ○ therapeutic interventions can also be performed hemodynamically unstable patients can localize exact site and cause no bowel preparation required ○ ○ ○ ○ embolization and vascular access site related side effects ionizing radiation and contrast related side effects cannot detect very slow bleed poor performance in variable arterial anatomy Catheter angiography (CA) ● Recommendation ○ ○ LGIB: initial modality of choice for hemodynamically unstable patients or recurrent/continuous bleeding after post colonoscopic treatment UGIB: acutely bleeding patients with negative endoscopy or where endoscopy could not find source Dual-energy CT techniques ● ● Principles ○ acquiring both high- and low-energy datasets through a volume of tissue enables one to estimate the radiation attenuation => subtraction image ○ ○ increased conspicuity of enhancing disease or extravasated contrast media lower the radiation dose Benefits ACR appropriateness criteria Upper Gastrointestinal Bleeding Endoscopy is the best initial modality and radiology does not play a significant role Four situations/variants where radiologic management is useful when endoscopy: ● ● ● ● Reveals non-variceal arterial bleeding source: CTA and CA (hemodynamically unstable) Reveals non-variceal bleeding but does not identify a clear source: CTA and CA Negative: includes obscure UGIB CA, CTA, CTE Contraindicated: in CA, CTA and CT abdomen with IV contrast Upper Gastrointestinal Bleeding Four variant scenarios ● ● ● ● Active bleed and are hemodynamically stable: colonoscopy is the most appropriate In terms of radiological modalities, CTA and scintigraphy (CTA has many added advantages) Active bleed and are hemodynamically unstable: CA Rebleeding/ongoing bleeding post colonoscopic treatment for LGIB: CA Intermittent or obscure bleed: CTE References Carney BW, Khatri G, Shenoy-Bhangle AS The role of imaging in gastrointestinal bleed Cardiovasc Diagn Ther 2019;9(S1):S88S96 doi:10.21037/cdt.2018.12.07 Wells ML, Hansel SL, Bruining DH, et al CT for Evaluation of Acute Gastrointestinal Bleeding RadioGraphics 2018;38(4):1089-1107 doi:10.1148/rg.2018170138 ... Upper GI bleeding (UGIB): bleeding originating proximal to the Treitz ligament Lower GI bleeding (LGIB): bleeding originating from the colon or rectum Suspected small-bowel bleeding: the upper... AS The role of imaging in gastrointestinal bleed Cardiovasc Diagn Ther 2019;9(S1):S88S96 doi:10.21037/cdt.2018.12.07 Wells ML, Hansel SL, Bruining DH, et al CT for Evaluation of Acute Gastrointestinal. ..Introduction Common causes of GI bleeding ● Upper gastrointestinal bleeding ● Lower gastrointestinal bleeding ○ ○ ○ ○ ○ esophageal, gastric and duodenal