Imaging of the Small Bowel
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Transcript of Imaging of the Small Bowel
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Imaging of the Small BowelCarmen Meier, MDMarch 24, 2012
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Small Bowel FactsConsists of: duodenum, jejunum, ileum20 to 30 feet longRoleDigestion of proteins, carbohydrates, lipidsAbsorption of nutrients
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Why image the small bowel?Structural problemsStrictures (medications, Crohns disease)Inflammation (Crohns, infection, ischemia)Masses or polypsForeign bodies (capsules)BleedingVascular ectasia (AVMs)Masses/tumorsPolypsMeckel's diverticulumDieulafoy's lesionUlcerations
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Radiology ImagingSmall Bowel Follow ThroughEnteroclysisCTTagged RBC scanAngiography
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SBFTPo radio-opaque contrast followed by serial x-raysPosition changes, abdominal pressure often neededUnable to see small lesions or mucosal lesions (AVMs)
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SBFTUseful for fistulas (Crohns disease)
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EnteroclysisInjection of contrast followed by methylcellulose through nasoduodenal tube. Contrast coats the intestine and the methylcellulose distends the lumen to help with visualization.
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EnteroclysisCon: nasoduodenal tube, uncomfortable, time-intensive
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CT EnterographyHigh volume (1200ml) negative oral contrast over 1 hour (no tube)improves small bowel distension c/w regular CTGive IV contrast to evaluate bowel wall
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CrohnsDiseaseCrohnsdisease
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Tagged RBC scanSmall amount of blood drawn and labeled with radioactive material (Technetium)Blood then re-injected and circulates: picked up by gamma scan
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Tagged RBC scanPro: may pick up slower bleedCon:Only approximate location givenDoes not pick up intermittently bleeding lesionsNo option for intervention
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AngiographySelective cannulation and contrast injection of blood vessels by interventional radiologist under fluoroscopy to pick up brisk/active bleeding
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AngiographyPro: Intervention possible (occlusion of bleeding vessel with coils, etc)Con:Fast, active bleeds onlyNeed at least approximate locationInvasiveHigh IV contrast load -> renal issuesNot available everywhere
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Endoscopic Imaging of Small BowelVideo Caspule EndoscopyPush EnteroscopySingle Balloon EnteroscopyDouble Balloon Enteroscopy
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Capsule EndoscopySmall capsule capable of taking sequential still images that are transmitted to receiver is swallowed by patient.Capsule disposable.Images downloaded from receiver and analyzed by MD.
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Capsule EndoscopyPro: NoninvasiveCon:No control over imagesUnable to interveneStill requires prepTakes some timeNot all patients suitable candidates
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Standard EnteroscopyPro:Able to interveneBiopsy, polypectomy, cautery, foreign body retrivalCon:InvasiveNot suitable for all patients
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Push EnteroscopySimply pushing a (pediatric) colonoscope (180cm) or dedicated enteroscope (200cm) into the small bowel as far as possibleLimitations:Uncomfortable (anesthesia)Small bowel is non-fixed, and therefore difficult to simply advance scopeLooping in stomach
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Single Balloon EnteroscopyPush-and-pull mechanismNeeded: Balloon Control Unit and single-use splinting tubeMost procedures take about 1 hourLimitations:Still uncomfortable for patient (anesthesia)Post-surgical anatomyContraindicated with varices
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Single Balloon Enteroscopy
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Double Balloon EnteroscopyOne balloon on endoscope, one on overtubeVisualization of more distal small bowelLimitations:Fujinon systemMore difficult to learn90-120 minutes procedure time
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Questions?