Lecture 26

Question 1

What are the characteristics of a normal stomach position on radiographs?

Answer 1

-fundus is left and dorsal
-pylorus is right and ventral
-body of the stomach is in between

Question 2

What is shown in this image?

Answer 2

normal stomach

Question 3

How does the appearance of the stomach differ between a right lateral radiograph and a left lateral radiograph?

Answer 3

-right lateral: fluid in pylorus, gas in fundus
-left lateral: gas in pylorus, fluid in fundus

Question 4

What is shown in this image?

Answer 4

normal right lateral view in the dog

Question 5

What is shown in this image?

Answer 5

normal left lateral view in the dog

Question 6

How does the position and shape of the stomach differ between dogs and cats?

Answer 6

*dogs:
-extends from left body wall to right body wall

*cats:
-predominantly within left cranial quadrant
-pylorus on midline
-“J” shaped

Question 7

What is shown in these images?

Answer 7

left: normal canine stomach

right: normal feline stomach

Question 8

What is shown in these images?

Answer 8

normal feline stomach

Question 9

What can affect the position and shape of the stomach?

Answer 9

-deep vs shallow chested animal
-effects of other organs

Question 10

Why is it important to fast an animal when taking radiographs of the stomach?

Answer 10

food can distend the stomach and cause it to appear larger than normal/when empty

Question 11

What is shown in this image?

Answer 11

normal post-prandial canine stomach

Question 12

What is shown in this image?

Answer 12

rugal folds within the fundus of the stomach

Question 13

What are the normal findings of the stomach on ultrasound?

Answer 13

-rugal folds
-thin wall that is distention dependent
-wall thickness around 2 to 5 mm
-wall layering present

Question 14

What is shown in these images?

Answer 14

normal stomach
-presence of rugal folds
-ability to assess gastric wall

Question 15

What are the characteristics of the small intestines?

Answer 15

-duodenum is in right cranial abdomen along body wall
-jejunum and ileum have smooth curves and are relatively mobile
-smooth margins
-diameter is variable; want to measure from serosa to serosa

Question 16

What is the average diameter of the intestines in dogs and cats?

Answer 16

dogs: less than 1.5x the height of the L5 vertebral body

cats: less than 12 mm

Question 17

What is shown in this image?

Answer 17

normal small intestines

Question 18

What are the normal imaging findings with regards to small intestinal lumen contents?

Answer 18

-should be relatively homogenous
-can contain gas or fluid/soft tissue opaque material
-fluid and gas separated by gravity may form a meniscus; looks similar to a thickened wall

Question 19

What is shown in this image?

Answer 19

fluid-opaque small intestinal contents
-NOT thickened wall

Question 20

What are the characteristics of the small intestinal wall on ultrasound?

Answer 20

-thin wall; around 4 to 6 mm thick
-mucosa and muscularis layers will be hypoechoic; lumen, submucosa, and serosa will be hyperechoic

Question 21

What is shown in these images?

Answer 21

normal small intestine on ultrasound
-can identify all layers on ultrasound

Question 22

What is indicated by the star-shaped icons in this image?

Answer 22

thickness of the small intestinal wall from lumen to serosa; approx. 4 mm

Question 23

What is the “string of pearls” or “pseudo-string sign” in cats?

Answer 23

-strong circular smooth muscle contractions and linear mucosal folds in duodenum and proximal jejunum
-causes small intestine to have a “string of pearls” appearance normally

Question 24

What is shown in this image?

Answer 24

“string of pearls” small intestinal appearance in cats

Question 25

What are the characteristics of canine peyer's patches?

Answer 25

-lymphoid aggregates in descending duodenum -can appear as "pseudo-ulcers" on imaging and cause a rough mucosal appearance

Question 26

What is shown in these images?

Answer 26

canine peyer's patch; normal

Question 27

What are the components of the large intestine?

Answer 27

*cecum -ileocecocolic junction *colon -ascending, transverse, and descending -descending colon usually along left abdominal wall *rectum -from entrance of pelvic canal to anal sphincter

Question 28

What are the characteristics of colon size?

Answer 28

-thin-walled, distensible tube -diameter less than 1.5x the length of the L7 vertebral body -wall thickness up to 2mm; may not see individual layers

Question 29

What is shown in these images?

Answer 29

normal large intestine in the dog

Question 30

What is shown in this image?

Answer 30

normal colon

Question 31

What is the preparation for GI contrast studies?

Answer 31

-start with routine radiographs -fast the patient -avoid sedation; can interfere with GI movement

Question 32

What are the indications for GI contrast studies?

Answer 32

-ultrasound not available -determine position -evaluate motility/function -further detail of survey radiographic abnormalities -abnormality suspected but not seen on survey rads

Question 33

What are the characteristics of liquid barium sulfate suspension as a GI contrast medium?

Answer 33

-relatively benign if aspirated -DO NOT USE if perforation is suspected -do not use before an endoscopy or ultrasound

Question 34

What is shown in this image?

Answer 34

aspiration of liquid barium sulfate suspension

Question 35

What are the characteristics of iodinated GI contrast medium?

Answer 35

-indicated if perforation is suspected -can be used prior to endoscopy -can cause acute pulmonary edema if aspirated -draws water into GI tract; can cause dehydration

Question 36

What are the characteristics of an upper GI study?

Answer 36

-typically using liquid barium -inadequate volume of contrast is the most common error in study -orogastric tubes permit more reliable delivery of contrast into the stomach -want a minimum of 3 views for the stomach and 2 views for intestines -suspected lesions should be seen on more than 1 radiograph -study ends when all contrast reaches the colon

Question 37

What are the characteristics of gastric emptying time?

Answer 37

-begins within 15 minutes of ingestion -complete within 1 to 4 hours

Question 38

What are the characteristics of small intestine transit time?

Answer 38

-contrast should be completely through the small intestine within 5 hours in the dog and 3 hours in the cat -no minimum for transit time

Question 39

Which factors can affect GI transit time?

Answer 39

-drugs -mental status -stress -insufficient volume of contrast media

Question 40

What is shown in these images?

Answer 40

normal upper GI contrast study in a dog

Question 41

What is shown in these images?

Answer 41

normal upper GI contrast study in a cat

Question 42

What are the characteristics of a pneumocolonogram?

Answer 42

-colonic contrast study -injection of gas into rectum to fill colon -main indication is to help identify colon location -low cost; can use room air

Question 43

What is shown in these images?

Answer 43

top: survey radiograph bottom: normal pneumocolonogram in a dog (lateral)

Question 44

What is shown in these images?

Answer 44

left: survey radiograph right: normal pneumocolonogram in a dog