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GIT Imaging FACTS 2
ADN Sydney Uni Year 2
42
Veterinary Medicine
Graduate
03/23/2011

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Cards

Term
What are the terms used to describe variations in plain radiographs?
Definition

Radiolucent

 

Radiopaque

Term

Gas in an xray is________________(radiopaque/radiolucent)

and __________(black/white)

Definition
Gas is radiolucent and black
Term

Bone in an xray is________________(radiopaque/radiolucent)

and __________(black/white)

Definition
Bone is radiopaque and white
Term
_______________(radiolucent/radiopaque) structures ABSORB all the rays before reaching the x-ray film
Definition
Radiopaque
Term
_______________(radiolucent/radiopaque) structures allow all the rays to reach the film
Definition
radiolucent
Term
What are some uses of plain radiography?
Definition

1. evaluate GIT abnormalities (including vomting, regurgitation, persitant diarrhea, ineffectual/pain during defecation, abd pain, abd masses, abd distention

2. screening procedure for diseases with obscure clinical signs

3. survey rads prior to contrast radiography

 

Term
What is the general procedure for plain radiography?
Definition

-fast 12 hours

-sedation/general anaesthesia (maybe)

-min 2 views, lateral (RL or LR) and VD (or DV but VD is preferred for GIT)

Term
What are the advantages of plain radiography? (5)
Definition

1. readily available

2. relatively eay to preform

3. interpretation difficult at first, but improves with experience

4. cost effective

5. multiple indications; provides lots of information

Term
What are the disadvantages of plain radiography? (5)
Definition

1. 2D of 3D structures which mean there is silhouetting and summation of overlapping structures

2. rarely give final etiologic disgnosis (although can indicate next step and give limited number of differential diagnoses)

3. may need GA or at least sedation

4. soft tissue structures can be difficult to visualize due to lack of contrast

5. uses ioinizing radiation

Term
What is positive contrast media and give exmaple
Definition

substances that are more radiopaque than bone therefore appear white on film

eg barium (liquid or BIPS) or organic iodinated contrast

Term
What is negative contrast media and give example
Definition

substances with low specific gravity that are more radiolucent than fat and soft tissue

eg air, CO2 O2

Term
What are some of the uses of contrast radiography?
Definition

-aid in visualization of internal architecture of an organ; allow detection of changes in size, shape, location, and mecosal pattern of an organ; to asses the mucosal surface and luminal contents of an organ 

-evaluate organ fucntion (motility, rate)

-investigate # of GIT abnormalities and clinic signs (vomiting, suspected abd masses, foreign bodies, abd pain, diarrhea, intussusception {where the one part of intestine invaginates another}, colitis)

-supplement of confirm information from plain rads

Term

What is the general procedure of contrast radiography?

 

Definition

Upper GIT:

fasted for 12-22 hours

contrast admin'ed orally or via tube

rads taken at intervals

final is taken 12 hours after admin of contrast

 

Lower GIT:

fasted for 36 hours

admin'd rectally

rads taken at intervals

 

both require:

evacuation of colon

cessation of drugs affected GIT

 

Term

Fill in the parts of the GIT that each of these types of procedures assess

barium swallow_____1______

gastrogram______2_____

Upper GIT series ______3______

Barium enema  _____4_______

Definition

barium swallow 1. Esophagus

gastrogram 2. Stomach

Upper GIT series 3. SI and to some extent the colon

Barium enema 4. Large intestine

Term
What are some advantages of contrast radiography? (4)
Definition

1. multiple indications and can provide more info than plain rads

2. relatively easy to preform

3. readily available

4. cost effective

Term
What are the disadvantages of contrast radiography? (6)
Definition

1. more invasive and still can have the problem of superimposed structures as with plain rad

2. aspiration of barium (potential for pneumonia and pulmonary granuloma formation)

3. if GIT perforation exists, leaking barium can lead to severe rxns

4. multiple rads make it time consuming and more expensive than plain rads

5. may require GA or sedation

Term
What are ome uses of fluoroscopy (dynamic contrast radiography)?
Definition

- assessment of swallowing

- complete functional examination of esophagus

- investigation of megaesophagus and presence of air/food in esophagus

- investigation of both site and functional problem involved in swallowing disorder

- investigation of regurgitation

- direct observation of gastric peristalsis and gastric emptying

Term
What is the general procedure for fluoroscopy (dynamic contrast radiography)?
Definition

-fasted for 12-24 hous

-for esophagus, 3-6 completed swallows of both solid and liquid boluses (barium impregnated)

Term
What are the advantages of fluoroscopy (dynamic contrast radiography)
Definition

1. enables direct assessment of esophagus FUNCTION

2. enables visualization of sequential changes in the shape of the stomach

3. enables good assesssment of motility

4. animal is conscious, so decreased chance of aspiration

5. cost effective (after equipment is purchased)

Term
What are the disadvantages of fluoroscopy (dynamic contrast radiography)
Definition

1. limited availablity

2. longer periods of radiation exposure for staff

3. limited indications

4. equipment is expensive

Term
What are the terms used to describe structures in u/s? and what color are they?
Definition

hyperechoic (or echogenic or echo rich)- white

hypoechoic (or echo poor)-blacker than above

echolucent (anechoic or echo free)-black

 

 

Term
What are the uses of u/s?
Definition

-assess motility (eg peristalsis in real time), assess wall thickness and architecture of the layers of the GIT, examination of luminal contents

-diagnose # of GIT abnormalities including gastric and intestinal foreign bodies, intussusception, GIT neoplasia, gastric ulcers and ileus

Term
What is the general prep for u/s?
Definition

-fasted

+/- sedation

abd is clipped

acousti gel is applied

Term
What are the advantages of u/s?
Definition

-superior to rads for studying soft tissue

-economical (cheaper and faster than contrast series)

- enables imaging in tomographic (cross sectional) plane

- permits id of internal structure of an organ or mass

- enables non-invasive evaluation of organ motility

-u/s guided biopsy

-portable

-safe, no radiation

-min prep is needed

Term
What are the disadvantages of u/s?
Definition

- gas and feces can prevent imaging of deeping structures

-hard to learn how to interpret (to use the tool and the know the normal anatomy)

-requires significant experience and expertise

Term
What are some uses of endoscopy?
Definition

- directly examine mucosal surface and some submucosal tissue

- investigate a # of problems including chronic regurgitation or chonic vomiting

- investigate animals with hx of straining to defecate, blood in feces, constipation or chronic dirrahea

Term
What is general prep for endoscopy?
Definition

upper GIT:

fasted for 18-24 hrs

deprived of water for 4-8 hrs

lower GIT:

complete evacuation of feces

fasted for 36 hours (for above) or pref 48-72 hours

multiple enemas

 

GA

Term
What are the advantages of endoscopy?
Definition

-permits examination of the mucosal surface, direct visualization of lesions and biopsy collection with min disturbance

-more likely to get definite diagnosis (compared to rad)

-no radiation or harmful chemicals

- rapid and relatively non-invasive technique with few post-op complications

- becoming more affordable

portable

Term

What are the disadvantages of endoscopy?

 

Definition

- not readily available

- thorough knowledge of anatomy required

- risks associated with GA

Term
What are some uses of CT?
Definition
- to visualize stomach, SI and colon
Term
What are the advantages of CT scans
Definition

- very high contrast resolution

- once data is collected, can be displayed in numerous ways

-CT uses very short scan times and therefore less chance of movement artefact

-oral/rectal contrast studies can be preformed

Term
What are the disadvantages of CT
Definition

-$$

-limited availability

-GA

- radition

- soft tissue not as good as MRI

- images are only obtained in the tranverse plane in which the patient is lying

- difficult to visualize abd organs without contrast studies

Term
What are the white/black areas referred to as in MRI imaging?
Definition

bright/white increased signal intensity

dark/black structures have decreased signal intensity

Term
MRI uses what type of waves for imaging?
Definition
radiowaves
Term
What are the advantages of a MRI?
Definition

- provides superior soft tissue anatomic detail, contrast and resolution

- no ionizing radiation

- images can be transverse, sagittal and dorsal planes with equally good definition

- contrast studies are also available

Term
What are the disadvantages of MRI imaging?
Definition

-$$$$

-Limited availability

- GA
- motion artefacts (esp with upper abd)

Term
put these structures in order of radiopaque to radiolucent: bone, fat, gas, mineral, muscle
Definition

Radiopaque

mineral

bone

muscle

fat

gas

radiolucent

Term
In a VD, the positive contrast will be where and the gas will be where?
Definition

contrast (radiopaque)- fundus and pylorus

gas (radiolucent)- greater curvature

Term
In a L-R, where will the contrast more likely be in the stomach?
Definition
in the pylorus, beginning of SI
Term
if the animal is L lateral recumbancy, where in the stomach would the contrast most likely be?
Definition
radiopaque in the fundus
Term
What is plication?
Definition

typical of linear obstruction

[image]

Term
what type of contrast imaging does this picture show?[image]
Definition
double contrast
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