Diagnostic imaging - abdomen Flashcards
When is serosal detail poor?
If no fat
Young
Peritonitis
Fluid
Neoplasia
Where is the spleen on radiograph?
Visible in dog on both progections, less visible on cat lateral
Head caudal to stomach on left
Tail usually mid ventral abdomen
What is the most common cause of ventral midabdominal mass?
Splenic mass
What can you use to assess liver size?
Gastric axis - usually parallel to ribs, perpendicular to spine
What are the differentials for a small liver?
Portosystemic shunt
Cirrhosis - end stage liver disease
Chronic hepatitis
What are the differentials of a large liver?
Acute hepatitis
Endocrine hepatopathy
Congestion
Focal mass lesion
What conditions can you identify from the position of the stomach on plain radiographs?
Hiatal hernia
Gastro-oesophageal insussusception
Diaphragmatic rupture
Dilation and volvulus
How do you tell if the small intestine is dilated?
Ratio of SI width to height of mid-body of L5
If ratio is less than 1.4 its no likely to be obstructed
If ratio is more than 2.4 it is very likely to be obstructed
What does a gravel sign mean?
Sign of chronic partial SI obstruction
Where are the colons anatomical positions?
Ascending - right mid-abdomen
Transverse - crosses caudal to stomach
Descending - left abdomen
Rectum - in pelvic canal
In dogs what should the colonic width not exceed?
3x normal SI
Shouldnt be longer than the body of L7
What is the definition of contrast media?
Agents that are more or less opaque than surrounding tissue
What does contrast media do?
Delineate organs/cavities within the body
To see structures that arent usually visible
To gain more info about structures
What is a positive contrast? What are some examples?
High atomic number
Eg. barium, iodine
Appear white on radiograph
What is a negative contrast? What are some examples?
Low density
Eg. Gases - air, CO2
Black on radiograph
When is barium used?
In the GI tract
Inert, cheap, palatable
NOT IV
When is iodine used?
Urinary tract - renal excretion
Injected IV
What are the two types of iodine contrast? Which is safer?
Ionic
Non ionic - safer
What are the advantages of negative contrast media (air or CO2)?
Cheap
Simple to use
Relatively safe
Can combine with positive contrast agents eg. double contrast in bladder
What are the disadvantages of negative contrast media?
Very small risk of air embolism
Poor mucosal detail, less contrast
What are the indications for a barium swallow?
Shows pharynx and oesophagus:
Dysphagia
Regurgitation
When do you not use barium?
If suspected rupture - use iodinated contrast instead
If risk of aspiration
What is the normal appearance of a cat oesophagus?
Herringbone appearance to smooth muscle of lower oesophagus
When should you only use liquid barium?
In a barium follow through study - by mouth or stomach tube
How do you do a barium follow through study?
Radiographs taken immediately after liquid barium swallowed
Then at intervals
Final image at 24 hours or when all barium is in colon
What are the indications for a barium GIT study?
Persistent recurrent vomiting
Or haematemesis
If palpable mass
If suspect anomaly on plain radiograph
What complications can barium cause?
Granulomatous pneumonia if aspirated
What are normal GI findings from contrast?
Duodenal pseudoulcers - indentations in lymphoid tissue
String of pearls appearance - from peristalsis
What do you use to evaluate the large intestine?
Barium enema - liquid barium infused into rectum post enema
Messy
Difficult to interpret - just do endoscopy
