Imaging of the GI tract Flashcards
(35 cards)
What is a ring down artefact?
Hyperechoic band distal to a a shadowing structure
Caused by exciting liquid trapped between gas bubbles
What type of trasducer should be used for the GI tract?
High frequency (7.5-10) May need lower for big dogs and deeper structures
What are the patterns that can be produced by luminal contents?
Gas - hyperechoic middle
Fluid - hypoechoic middle
Alimentary (food) - middle is similar to rest of tract
Mucous - less hyperechoic than fluid - how would normally appear in a fasted animal
How are the canine and feline stomachs different?
Dog - boomerang shape pancreas, long axis of the stomach is perpendicular to the spine
Cats - stomach is more angular. Pyloric antrum on the midline. Left pancreatic limb much larger than the right
How can you differentiate different gastric wall diseases?
Thickening can occur with neoplasia or inflammaroty dieases (with or without loss of layering)
Anything over 10mm likely to be neoplastic
Ulcers can appear mass like and lymphoma can present as preserved layering just thickened, so always biopsy
What are the common gastric neoplasias?
Cats - lymphosarcomas
Dogs - adenocarcinomas
Leiomyomas may be incidental findings
How may gastic ulcers appear on U/S?
Normally in pyloric region
Focal gastric thickening
Often combined with loss of normal layering
may be able to see a crater and hyperechoic foci (gas)
Where can you identify the descending duodenum
Most dorsal loop with a straight course in the right cranial abdomen
How may peristalsis change with intestinal disaese
Movement normally reduced with obstructions/ periotonitis, although you can see temporary increases.
How may linear FBs appear on US?
Plication of the intestines
How do intususscpetions appear on US?
Multilayered appearance of the intestines
Normally at the ileocolic junction but can be anywhere
May lose wall layers due to oedema
Entrapped mesenteric fat can appear hyperechoic alongside the intususcepted segment
Can crudely assess for viability with doppler
How do inflammatory conditions normally appear in the intestines?
Mild to moderate thickening of the small intestines
Mainly involving the mucosa/ submucosa
May appear normal
What does corrugation of the intestinal walls suggest?
Pancreatits
Severe intestinal inflammation
Peritonitis
Infiltrative neoplasia
How can lymphangiectasia appear?
Hyperechoic mucosal striations
snow storm appearance
What do lymph nodes look like?
Slightly hypoechoic or isoechoic to the mesentry
How may peritonitis look?
Mesentry becomes more hyperechoic
Loses its granular texture and becomes uniform
Other organs hard to see clearly
FF
Where can you find the left and right limbs of the pancreas?
Right - with proximal duodenum
Left - Between the greater curvature of stomach cranially, colon caudally, splenic vein dorsally
May be able to see pancreatic ducts in cats
How would the pancreas look with pancreatitis?
Acute pancreatitis - thickened, hypoechoic, surrounding mesentry hyperechoiccorrugated appearance of the duodenum
Chronic - can be minimal changes, may be heterogenous with areas of increased echogenicity due to fibrosis/ mineralisation
What radiographic signs of small intestinal obstruction are there?
Plication of the intestines
Segmental dilation of the intestine with SI:height of L5 >2.07 = 90% chance of obstruction
Abnormal appearance or location of the bowel
Focal accumulation of granular tissue in the small intestine
Visible FB
Mottle gas appearance should raise suspicion, esp for a textile FB
What ultrasonographic signs of small intestinal obstruction are there?
GI dilation - particularly likely if there is jejunal dilation with normal wall
Abnormal motility
Changes in wall thickness
FF
Hyperechoic structure with distal acoustic shadowing
How useful is U/S in diagnosing gastric neoplasia
Some can be missed! - Should do endoscopy too if NAD
Gas and food can create artefact, but an empty stomach can make the wall look thicker than it is
Lymphoma is the most commonly missed gastric neoplasia on U/S
Where does liquid and gas go on lateral radiographs and how can that help image the stomach?
Gas - on the non-dependent side (upper)
Liquid - on the dependent side (lower)
Pylorus is on L side of abdomen so with gas is visible on a R lateral
Fundus is on the R side of the abdomen
What does gas within the liver normally suggest?
Hepatic abscess, but can be other things
How should the liver appear on radiography?
Most cranial abdominal organ
Should be all or very nearly all within the costal arch
Caudal margins should be sharp
The gastric axis should be within a line parallel to the ribs and perpendicular to the spine - if not this suggest micro or macrohepatica
