1Gastrointestinal Special ProceduresKari L. Anderson, DVMUniversity of MinnesotaLearning ObjectivesBe able to:• List indications, contra-indications, complications• Choose the appropriate contrast procedure• Describe special procedure– contrast/dose– preparation– views• Answer questions pertaining to normal findings• Answer questions pertaining to basic abnormal interpretationGI Special Procedures• Function• Morphology2GI Special Procedures• Esophagography• Upper GI series– gastrogram• Pneumocolon• Barium enemaGI Special Procedures• Indications• Contra-indications/complications• Contrast media/dose• Preparation• Technique• Normal interpretation• Abnormal interpretationGI Contrast Media• Barium sulfate suspension– contrast media of choice– commercial preparation• micropulverized barium sulfate• suspending agents• deflocculating agents• preservatives• flavoring agents3GI Contrast Media• Barium sulfate suspension– can purchase “high density” preparation• dilute with tap water to desired concentration•Barium sulfate paste/cream– thicker adherent creamy preparation– excellent mucosal adherence• Also adheres to foreign bodies GI Contrast Media• Water-soluble, iodine-containing contrast– May be chosen in cases of suspected perforation– commercially available oral preparations or use IV preparations – not irritating to mediastinal, pleural, and peritoneal cavities like bariumGI Contrast Media• Water-soluble, iodine-containing contrast (compared with barium sulfate)– More expensive– Hyperosmolar (ionic)• May worsen dehydration• Becomes diluted– Irritating (ionic)• More likely to cause emesis• More rapid transit through intestinal tract– Difficult to visualize small leaks– May be absorbed systemically4EsophagographyEsophagography• Function– Fluoroscopy– Serial static radiographs• MorphologyIndications• Abnormal survey radiographs• Historical findings• To outline lesions of esophagus• To evaluate location of esophagus• To study function5Contra-indications (relative)• Fluid-filled megaesophagus• Severe regurgitation• Suspected perforationComplications• Aspiration of contrast– Barium relatively inert– Worse if compromised lung• Leakage of barium into mediastinum or pleural cavitiesContrast Media• Barium cream/paste• Liquid barium suspension– Mixed with wet and dry food• Iodinated contrast• 5-20 ml6EquipmentPatient Preparation• Not really needed• Fast for 4-6 hours– empty stomach– a hungry patient is a cooperative patient!Technique• Survey radiographs– Assess esophagus/other tissues– Select technique• Sedation?• Administer contrast• Obtain radiographs7Case Example• 1.5 year old, MN, Rottweiler• Pelvic surgery after being HBC • Regurgitated during anesthesia• Presents 7 days later with a fever, painful, anorexicCase ExampleWhich contrast do you wish to use?a. Barium sulfate pasteb. Barium sulfate suspensionc. Ionic, iodinated contrastd. Non-ionic, iodinated contraste. Air Normal Interpretation (function)• Easily forms bolus with tongue• Bolus stimulates coordinated swallow– Contraction of pharynx– Dorsal arching of soft palate to close nasopharynx and closure of epiglottis– Relaxation of upper esophageal sphincter• Swallow stimulates good primary peristalsis of esophagus• Secondary peristalsis moves any residual8Dynamic EsophagographyNormal liquid swallowNormal liquid swallow9Normal food swallowNormal food swallowNormal Interpretation(structure)• Minimal coating in oropharynx• Longitudinal folds of mucosa• “Herringbone” pattern of cats• Redundant esophagus10Normal dogNormal dogNormal dog11Normal catNormal diverticulumNormal InterpretationNormal location– Midline dorsal to larynx– Left of trachea in cervical region– Dorsal and to right at aortic arch– Near midline in caudal thorax12Abnormal Interpretation (function)• Poor bolus formation• Uncoordinated swallow• Reflux into nasopharynx or trachea• Poor or lacking primary peristalsis• Diminished secondary peristalsisAbnormal functionAbnormal Interpretation (structure)• Intraluminal– Filling defects– Luminal distension• Intramural– Wall thickening– Mucosal irregularity– Distortion of mucosal folds• Extramural– Deviation of esophagus13IntraluminalIntraluminalIntramural14IntramuralIntramuralIntramural15IntramuralExtramuralExtramural16ExtramuralImportance of complete studyCase ExampleA client brings in her older golden retriever because he has a difficult time eating. The dog makes many attempts to swallow, and sometimes he gags after these attempts. He also has regurgitated. Thoracic radiographs reveal some aspiration pneumonia, but no other abnormalities. Which study do you recommend for the best evaluation of these signs?a. You only need survey radiographsb. Esophagogram (conventional)c. Esophagogram with fluoroscopy17Case ExampleCase ExampleWhat type of lesion is this?a. Intraluminalb. Intramuralc. Extramural Upper Gastrointestinal Series18Upper GI Series• Gastrogram– positive contrast– double contrast– negative contrast• Small intestine• Not for evaluation of large intestineThe cheapest GI special procedureThe cheapest GI special procedure – opposite lateral19Upper GI Series• Morphology• FunctionIndications• Acute or chronic vomiting• Hematemesis• Anorexia• SI diarrhea or melena• Suspect obstruction• Suspect linear foreign body• Cranial abdominal mass lesion• Position of intestinal tract• Suspect perforationContra-indications (relative)• Survey radiographs show obstruction• Known or suspected perforation• Prior use of motility altering drugs• Food in stomach or feces in colon20Complications• Aspiration of contrastComplications• Aspiration of contrast21Complications• Leakage of contrast into peritoneal cavityComplications• Leakage of contrast into peritoneal cavityContrast Media• Barium sulfate suspension– 30% weight/weight– 6 ml/lb• Iodinated contrast– 1-2 ml/lb diluted with tap water to make 6 ml/lb2223Patient Preparation• Important!– especially for functional studies• Fast for 12-24 hours• Warm water enemasEquipment24Technique• Survey radiographs– evaluate need for study– ensure proper preparation– establish radiographic technique• Sedation?– Dogs: acepromazine– Cats: ketamine/valiumTechnique• Administer contrast via