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Abdominal Imaging 4

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sihirlifil's version from 2017-11-30 22:13

Intestines

Question Answer
How can we see the normal brush border mucosal surface of the gas-filled duodenum & small intestine?Barium
Which structure at arrows? Cecum: wider lumen, corkscrew shape
Pseudoulcers (outlined by barium)
What are pseudoulcers caused by?Peyers patches on ANTIMESENTERIC wall of duodenum
Species? normal?
NORMAL “string of pearls” duodenum of CAT
Normal?
Nope! filling defect in lumen of descending duodenum due to ascarid worm
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Pancreas anatomy & ultrasound

Question Answer
Local peritonitis
Poor abdominal contrast & serosal detail in cranial abdomen, ground glass appearance
This 4-year-old terrier presented for vomiting and dullness… whats wrong with him?
Pancreatic carcinoma
Caudally displaced gastric axis (pylorus to midline)
Poor serosal detail in right cranioventral abdomen
Stubby arrows are what? How is the serosal detail at long arrow?
Lateral displacement of descending duodenum & medial displacement of ascending duodenum. Due to pancreatic swelling
Poor serosal detail in R cr abdomen (local peritonitis)
Where is the L limb of the pancreas? How does it look on US?Medial to the spleen
Lacy hypoechoic structure with no clear capsule
Where is the R limb of the pancreas? How does it look on US?Medial to the duodenum
Large arrow = pancreaticoduodenal vein. Markers: duodenal wall thickness 0.29cm (Normal)
What’s going on?
Pancreatitis
Swollen, hypoechoic right limb, adjacent hyperechoic (due to inflammation) fat
This US of the right limb is showing what?
Mottled & swollen appearance, hyperechoic fat due to early abscessation (discrete anechoic area)
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Ileus & intestinal conditions

Question Answer
Kinds of ileus?Functional/Non-obstructive/Dynamic
Mechanical/obstructive/adynamic
How does functional ileus present?Hyper or hypomotility (depends on cause)
Underlying cause rarely identified
How does mechanical ileus present?Severe, focal distention (often acute presentation)
Hyper or hypo (chronic) motility
Cause of obstruction usually found: FB, neoplasia, intussusception…
Chronic phase of intestinal obstruction: pathogenesisReduced peristalsis --> fluid & gas accumulation continues --> dilatation of intestine cranial to obstruction may become locally severe in adjacent loop, more generalized distention of loops of intestine, may see gravel sign
Survey radiography quantitative guideline: a small intestinal diameter ___ (#) times the depth of the mid-body of the ___th lumbar vertebra suggests obstruction>1.6x the 5th lumbar vertebra
Typical pattern of ileus for a chronic FB obstruction in distal small intestineGeneralized
Generalized ileus with marked distention of whole intestine
Cause of obstruction: A? B? C?
A: Mural lesion compressing lumen, e.g. tumor
B: Intraluminal curved object e.g. FB
C: intraluminal radiolucent object e.g. material (corn on the cob)
Arrows?
Circular radiolucent structure in mid abdomen- rubber ball in ascending duodenum
Where does intestinal distention occur with duodenal FB?Proximal. Gas induces vomiting, therefore local distension not seen on radiographs
Partially radiopaque FB in descending duodenum- peach pit. No gas distension cr to FB (no vomiting)
Which artifact seen on this US? Cause?
Acoustic shadow due to FB in duodenal lumen (short arrow)
Top arrow? Bottom?
Focal ileus in descending duodenum
Plastic FB in ascending duodenum causing obstruction
What is a gravel sign? Cause?Chronic intestinal obstruction
Causes: radiolucent FB, chronic intussusception, tumor
Gravel sign
What is typical of linear FB on radiographs?Corrugated, plicated or bunched up appearance of small intestines
This cat was presented to your clinic, you do a contrast study. Which contrast medium? Dx?
IODINATED, NOT barium! This is a linear FB
Ultrasound is the preferable method of confirming diagnosis
What condition?
Ileus
Distended lumen of SI filled with gas
What condition?
IBD
Thickened bowel wall predominantly affecting mucosa
A 7yo FN crossbred dog presents with chronic v+/d+. These US show?
IBD, thickened bowel walls
Intussuscipiens =outside part
Intussusceptum =inside part
Arrows? Problem?
Radiolucent area (filling defect) within descending colon, surrounded by halo of barium = intussusception
Preferred imaging method for intussusceptionUS
Intussusception of ascending colon
Typical appearance of intussusception on USSwiss roll appearance: circular in cross section (bulleye)
A 12yo male DSH presents with chronic weight loss & palpable abdominal masses:
Neoplasia
Marked disruption & thickening of bowel walls
A 12yo crossbreed dog presents with abdominal pain, hx of splenic neoplasia:
Neoplasia eccentric thickening of bowel wall (neoplastic infiltration)
US features for Ddx: InflammationThickening but layering pattern usually preserved
Generally diffuse
Any layer might be affected (mucosa & submucosa more common)
Does not cause obstruction
US features for Ddx: NeoplasiaLayering pattern usually disrupted
Generally focal
May cause obstruction
Main ddx = lymphosarcoma
Infiltrative bowel disease, irregular serrated mucosal outline in distal ileum (US preferred method of imaging)
NORMAL barium enema: which structures pointed at?
Top: Cecocolic junction
Bottom: cecum
Ascending, transverse, & descending colon
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Colon Ultrasound & Hernias

Question Answer
Short arrows? Long?
Short = colonic wall
Long = dirty acoustic shadow from gas & air in lumen
Where does the colon lie relative to bladder?Dorsal
Annular mural carcinoma
Constriction of colonic lumen, causing fecal retention & concretions (long arrow = fecolith)
Severe megacolon
Large fecoliths extending full length of colon, causing ileus cranially (in small intestines)
Rectal diverticulum from perineal hernia, at caudal extent of rectum, diverging to right
Signs of abdominal wall herniaDisruption of abdominal contour
Abdominal organs in soft tissue swelling
US often useful
Ventral hernia
Problem? something else to note?
Ventral hernia
Also see subq emphysema under the skin & ventral to where abdominal wall should be
Arrows?
Loops of intestine contained in subq inguinal mass (hernia!)
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