Small animal special procedures Flashcards
Special procedures indicated for
Special procedures supplement or confirm information gathered from routine survey radiographs
Soft tissue structures or organs can be difficult or impossible to identify on regular films due to lack of contrast
Contrast media is administered to
Increase radiographic contrast within an organ or system
Visualize structures for size, shape and position
Identify defects in mucosal surfaces or luminal contents
Evaluate organ function or assess the physiological condition of that organ
Choice of contrast media is made by
Type of study
Condition of patient
Possibility of side effects
Positive contrast agent type
Barium or iodine
Positive contrast agents work by
Have components of high atomic number so absorb more x-rays than soft tissue or bone
This high absorption causes them to appear white on radiograph
Used to fill or outline a hollow organ
Can be injected into blood vessels**
Negative contrast agents are
Consists of air, oxygen, carbon dioxide and nitrous oxide
Negative contrast agents looks like
Low specific gravity so more radiolucent than soft tissue
This causes them to appear black on radiograph
Enhances contrast between various soft tissues
Produces less mucosal detail than positive media
Barium sulfate is
White powder, colloid suspension or paste
Given orally or rectally
Contraindications for barium
Media of choice for gastrointestinal studies as it is completely insoluble
Will not be diluted by alimentary secretions
Not absorbed through intestines
Disadvantage of barium
Because barium does not absorb or breakdown, if GI tract has perforation the barium can pass through the perforation into thoracic or abdominal cavity and remain there indefinitely
If perforation is suspected use soluble iodine first
Able to be quickly absorbed by the body
If iodine study is negative, can then follow up with barium series
There is also the possibility of granulomatous reaction
Barium impregnated polyethylene spheres (BIPS are
Used for evaluation of gut motility and transmit time
Two sizes
5 mm and 1.5 mm
Patients given 10 large spheres and 30 small spheres
Must follow manufacturer guidelines closely
Frequency of x-rays determined by tentative diagnosis
Iodine preperations
Generally used for intravascular or injected into body cavities
Water soluble
Rapidly excreted by kidneys
Most of the media is out of the body in 24 hours
Two types of iodine
Ionic and non-ionic
Ionic iodine characteristics
3 iodine atoms to 2 particles in the solution
Also known as high-osmolar contrast agents
HIgher risk
Non-ionic iodine characteristics
3 iodine atoms to 1 particle in the solution
Also known as low-osmolar contrast agents
Close to being isotonic, so reduced risk
Is more viscous and more expensive
Double contrast studies is and benefits
Use both positive and negative medias
Benefit:
-Optimum mucosal detail without masking small anomalies
Patient preparation for contrast studies
Vital to diagnostic radiographs
Withhold food for 12 hours prior to study to ensure GIT empty
Food in GIT can obscure/hide areas of interest
Enema can be given minimum of 4 hours prior to procedure
Sedation or anesthesia may be required for some procedures
Be aware of contraindications!
Make sure hair coat is clean, dry and free from debris/mats
Make sure no contrast media on patient, x-ray table, or cassettes
Remove collars and harnesses
Why do you take survey radiographs
Ensures patient is suitable for the study
GIT clean, no causative agents seen without aid of contrast
Ensure technique selection is appropriate
Prevents any waste of time of money
Types of special procedures
Esophagram
Upper GI Study*
Lower GI Study*
Retrograde Cystography
Excretory Urography
Pneumocystogram/Cystography*
Urethrography
Myelography
Upper GI study is preformed when and indicated when
Performed to evaluate stomach and small intestines
Indications:
Recurrent unresponsive vomiting
Diarrhea
Hematemisis
Melena
Abnormal bowel movements
Foreign body or obstruction
Chronic weight loss
Persistent abdominal pain
Procedure for barium studies
Barium administered orally per os via stomach tube
Contraindicated if perforations suspected – use caution
Can be replaced with endoscopy or ultrasonography
Make sure to give the complete volume for proper distention
When to take images in barium abdominal series
Immediate films:
VD, DV, left and right lateral
May oblique 15 degrees to right to view pyloric sphincter
At 15, 30, and 60 minutes
VD* and right lateral
Every hour after
VD and right lateral until barium is all in the colon
May also require a 24 hour radiograph
Lower GI barium enema indications
Performed to evaluate cecum, colon and rectum
Indications:
Abnormal bowel movements characterized by:
Excessive mucus
Bright red blood in feces
Painful defecation
High frequency diarrhea
Also used to detect:
Intussusceptions
Rectal mass
Abdominal mass
Stricture
Colonic obstruction
Commonly replaced by endoscopy
Lower Gi study patient preparation for barium enema
Animal fasted 24-36 hours (allowed water until 4 hours prior)
Make sure patient properly hydrated, increased risk if dehydrated
Perform enema 4 hours prior to procedure
Use sedation or anesthesia
Avoid narcotics
Contraindication: bowel perforations (as per UGI study)
Use contrast media at room temperature or slightly warmer
Lower GI procedure for barium enema
Patient in lateral recumbence
Insert lubricated Foley catheter tip into rectum and inflate balloon
Should be located just inside internal anal sphincter
Attach catheter to infusion bag or syringe
Infusion bag only needs to be slightly higher than patient
Slowly infuse barium until have reached desired distension
Radiographs needed for lower GI barium series
VD, right and left lateral
Oblique if necessary* - removes portions of colon away from lumbar spine and os penis
Evacuate the colon
VD and lateral post evacuation may be required
Double contrast can also be performed at this time by adding air to colon once evacuated
Remove catheter
Contrast study of the urinary system is for and indicated when
Evaluates kidneys, ureters, bladder, urethra, and prostate
Indications:
Hematuria
Proteinuria
Crystalluria
Polyuria
Isosthenuria
Dysuria
Pyuria
Etc….
Do you use barium in the urinary tract
NO NEVER USE BARIUM
What has replaced contrast studies in urinary
Ultrasound
Cystography is
Introduction of contrast into bladder via urinary catheter
Positive, negative or double contrast studies can be used
Sedation recommended
Precautions for cytography
Leakage of iodine around catheter giving contrast artifacts
Do not over distend bladder
Must maintain aseptic technique
Patient preparation for cystography
No food for 24 hours, water ad libitum
Enema the night before or at LEAST 4 hours prior
Obtain urine samples for lab BEFORE injection of contrast media
Dehydration must be corrected before procedure
Empty bladder before injecting contrast media
Cystography procedure
Insert lubricated catheter using sterile technique
Introduce contrast media
For double contrast study:
After introduction of positive contrast roll patient side to side then introduce the negative contrast
Radiographs required for cytography
Survey radiographs
VD and right lateral
After injection of contrast media
VD, left and right lateral
May require oblique VD to move bladder off lower lumbar spine
Especially for males with prostate or urethral issues
Excretory urography is and how to do
Used to be called IVP or IVU
Intravenous pyelogram/urogram
Intravenous injection of water soluble iodine to evaluate kidney structure and collection system
Patient preparation is the same as cystography
Inject warmed contrast media within two minutes
Flush IV catheter with heparinized saline
Excretory urography required radiographs
Immediately take VD
At 5 minutes take VD and right lateral
If evidence of contrast in kidneys may apply compression
At 15 – 20 minutes take VD and right lateral
If compression was applied, now remove it
At 30 – 40 minutes take right lateral and VD oblique
Urethrography is
Sedation is required
Consists of filling the urethra with contrast media
Precautions as per cystogram
Urethrography used to detect
Urethral trauma
Stricture
Obstruction
Tumors
Etc…
Urethrography required views
Lateral view as contrast is being infused into urethra
VD or oblique if needed
Fistulography is
Injection of positive or negative contrast into a fistula to determine extent of tract
Water soluble iodine is used with a Foley catheter
Contrast is infused into fistulous tract until just begins to leak past the catheter
Fistulography required views
Required radiographs:
Lateral and VD/CC/DP
May require films 3-4 min post injection
Myelography is
Introduction of positive contrast into subarachnoid space of spine via a spinal needle
Replaced by Computer Tomography (CT) or Magnetic Resonance Imaging (MRI)
Myelography is indicated
Indicated to highlight lesions within the spinal column such as:
Compressions
Masses
Protruding discs
Vertebral abnormalities
Spinal cord swelling
Procedure for myelography
General anesthesia require
Site of injection is surgically prepared
Spinal needle inserted
Any spinal fluid required for diagnostic testing is now taken
Slow injection of positive iodine preparation into subarachnoid space of spinal cord
Radiographs needed for myelography
Lateral and VD at site of suspected lesion
Contrast agents for other modalities
Computed tomography uses non-ionic contrast agents
MRI will use chelated gadolinium that is injected IV to differentiate one tissue from another
Scintigraphy or Nuclear Imaging uses radioactive contrast agents
