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What is the radiographic technique for abdominal rads for small animals and large animals?
- SA: fasted ideal, 3 views, diaphragm to pelvic inlet
- LA: fasted ideal, standing laterals, diaphragm to pelvic inlet
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Where will gas in the stomach be in left lateral, right lateral, VD, and DV?
- Left lat: pyloric antrum
- Right lat: fundus
- VD: body
- DV: fundus
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What is a difference between dogs and cats as far as stomach?
- Dogs tend to have long axis of stomach perpendicular to spine, stomach straight and sometimes U-shaped
- Cats have a J-shaped stomach, the pyloric antrum is barely to the right of midline
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Causes of an abnormal looking stomach on rads. (8)
- gastritis: wall thickening (really need contrast to see this)
- FB: difficult to see in stomach
- pyloric outflow obstruction: mass, FB, hypertrophy, gastroduodenal intussusception- positive gastrogram, beak sign, maybe distended stomach (if chronic)
- gastric masses: intra-luminal versus extra-luminal
- ulceration: double contrast gastrogram best to detect
- perforation: EMERGENCY, pneumoperitoneum; secondary to GDV, neoplasia, FB
- gastric dilatation: gas- aerophagia, drugs; food- outflow obstruction, overeating
- GDV: EMERGENCY,gas or food distention, compartmentalization, displacement, splenomegaly, pneumoperitoneum
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How do you diagnose a GDV?
- RIGHT LATERAL RADIOGRAPH
- gas-filled pyloric antrum (should only be seen on left lateral, but it is seen on the right when the stomach is twisted)
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How do you diagnose a gastric perforation with a GDV?
- horizontal beam x-ray
- (patient in left lateral recumbency b/c you need the fundus gas far away from the peritoneal gas you are trying to see)
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What is the normal location/ appearance of the intestines and duodenum on radiographs?
- Intestines: great variance, spring of pearls is normal feline peristalsis, mobile and easily displaced
- Duodenum: mid-abdomen on lateral, right abdomen on VD
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What is the normal location and appearance of the cecum and colon on radiographs?
- Cecum: mid-dorsal abdomen to the right of midline; C-shaped, often gas filled in a dog
- Colon: question-mark shaped, can be difficult to distinguish from small intestine, cats normal to have a lot of feces and gas
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What are the types of ileus and causes of each?
- Mechanical: FB, intussusception, Mass, +/- stricture
- Functional: enteritis (dietary indiscretion, inflammatory, infectious), drug induced, neuromuscular, infiltrative disease (IBD, lymphoma), mesenteric volvulus
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How might ileus appear radiographically?
- may be radiographically normal
- Usually focally (mechanical)or diffusely (functional) dilation of intestines
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How does a mechanical obstruction appear radiographically?
- distention with gas and/or fluid of some bowel loops AND empty bowel loops
- sentinel loop- the big, dilated, abnormal bowel
- Gravel sign- chronic partial obstruction
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How do linear FB appear radiographically?
- [string, tinsel, towels, mops, hosiery]
- characteristic plication
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What is the Gravel Sign?
- irregular mineral opacities in the intestines that does not change over time
- Chronic partial obstruction, usually a mural mass
- Smaller area for ingesta to pass through, so particles get stuck
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What do you see radiographically with obstruction of an equine patient?
fluid lines at many different levels- mechanical obstruction of the small intestine
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Where so linear FB get stuck in dogs most commonly? In cats?
- Dogs- pyloric antrum
- Cats- under the tongue
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If you identify a linear FB on radiographs, what is the next question you ask yourself?
Is there perforation?- free gas? decreased detail with free fluid?
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What are common mural masses causing obstruction? (2)
primary GI neoplasia- adenocarcinoma, lymphoma
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What do extra-mural masses often lead to?
- displacement of bowel
- partial obstruction (except: equine strangulating lipomas)
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Describe presentation of intussusception and radiographic findings.
- often preceeded by diarrhea, hypermotile phase
- sausage shaped soft tissue mass
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What are differentials for obstructions? (6)
- FB
- intussusception
- mass (intramural or extramural)
- less common: stricture, hernia, entrapment/ torsion
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What is the classic radiographic sign for intussusception?
well-defined, C-shaped soft tissue opacity, surrounded by gas
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What are causes of functional ileus? (6)
- mesenteric voluvlus- EMERGENCY
- inflammation (peritonitis, enteritis)
- pain
- autonomic nervous system disorder
- post-op
- drugs
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What is an abnormally large large intestine in a dog?
>1.5 times the length of L7
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How does perforation appear radiographically?
- free peritoneal gas and/or fluid
- secondary to obstruction, FB, neoplasia, trauma
- often with peritonitis
- EMERGENCY
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Differentials if the intestines are displace ventrally, dorsally, abaxially (on VD), and axially (on VD).
- Ventrally: retroperitoneal mass/ organomegaly
- Dorsally: peritoneal mass/ organomegaly
- Abaxially: peritoneal mass/ organomegaly
- Axially: enlarged uterus
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What are the types of positive, negative, and double contrast GI studies?
- Positive: barium liquid, non-ionic iodinated hexol (if suspect perf)
- Negative: room air
- Double contrast: positive first to coat, then negative added (best to measure wall thickness)
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What are the steps for an upper GI contrast study? (4)
- 1. fasted patient
- 2. survey radiographs (3 views) +/- enema
- 3. Give enough contrast (via orogastric tube)
- 4. take images until study is complete (when we see the obstruction, contrast is out of stomach and in colon)
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What are contraindications for upper GI contrast studies? (5)
- dehydration (contrast pulls fluid into the GI tract)
- radiographic Dx of mechanical obstruction
- free peritoneal gas
- septic peritoneal fluid
- obvious material in stomach
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On a positive contrast gastrogram, gastric emptying should start within _________ and should be complete in __________.
15 minutes; 2-4 hours
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Negative contrast gaastrograms are best for... (3)
location (of GI structures), FB, and mural masses
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Positive contrast gastrograms are best for... (5)
location (of GI structures), motility, obstruction, emptying, FB
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Double contrast gastrograms are best for... (2)
mucosal lesions (tumors, ulcers), FB
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What is a beak sign?
- pyloric outflow obstruction
- seen with positive contrast- thin pyloric-duodeno junction
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What is the use of lower GI (colon) contrast studies? (3)
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