contrast radiology of spinal canal
What can a myelography detect?
- spinal cord compression
- masses in or around the spinal cord
What could cause a spinal cord compression?
- protruding disc
- vertebral abnormalities
- spinal cord swelling
Are myelographys common in an average veterinary practice?
Which veterinary practices usually do myelographs and why?
- teaching hospitals and referral surgery practices
- strongly considering for surgery
What is the most common reason we do a myelograph?
IVD (intervertebral disc disease)
What are some indications for doing a myelograph?
- neurological deficits of limbs
- localize spinal lesion for surgery
What are some neurological deficits of limbs?
- sensory deficits
- spinal pain
- proprioceptive deficits
What is proprioceptive deficits?
animal does not know where its feet are
What is proprioception?
the sense of movement and position
Is myelography dangerous?
Why is a myelograph so dangerous?
can cause seizures and death
What are the contraindications for myelography?
- not for minor problems
- not for confirmation of diagnostic lesions on survey radiograph
- recent myelography
- history of seizures
- presence of infection or blood in spinal cord
What procedure should you do before a myelography?
What does CSF stand for?
What do we need to do a CSF tap for a myelograph?
to place contrast material around the spinal cord
Where is CSF located?
in the subarachnoid space between arachnoid and pia mater
What do we analyze when we do a CSF analysis?
- WBC count
- C & S
What kind of contrast agents can we use for a myelograph?
water-soluble iodine compounds (metrizamide, iohexol)
What kind of anesthesia is required for a myelograph?
deep anesthesia because there can be no movement of the patient
What kind of premedications should we use for a myelograph and which one should we avoid?
- we should use diazepam or any other medication with anticonvulsants
- we should avoid acepromazine because it lowers the seizure threshold
Where do we do the surgical prep for a myelograph?
- where spinal tap is to be done
- cervical - cisterna magna, lumbar area
Why is it important to minimize the risk of infection when doing a myelograph?
because patients are often given corticosteroids which can increase risk of infection
Who does the spinal tap?
What do we need to closely watch for when we are recovering a patient from a myelograph?
What is arthrography?
contrast study of joint space - shows articular surface
What are some indications for doing a arthrograph?
- joint pain unidentified by other methods
- ruptured joint capsule
- cartilage flap (osteochondritis)
- meniscus injury in stifle
What is better an arthrography or a arthroscopy?
What are some contraindications for doing a arthrograph?
- infection of joint
- infection of tissue around the joint that the needle must go through
What contrast agent do we use for an arthrography?
iodine - diluted to 20 mg iodine/ml
Do we ansethetize the patient when doing an arthrograph?
After we inject the contrast agent with a needle into the joint what should we do?
flex joint to distribute contrast material
What is pneumoperitoneography?
injection of gas into peritoneal cavity to outline abdominal viscera
What are some indications for doing a pneumoperitonegraphy?
- determine size
- contours of organs
What are some contraindications for doing a pneumoperitonegraphy?
- diaphragmatic hernia
- abdominal abscess
- abdominal fluid accumulation
What contrast agents do we use for pneumoperitonegraphy?
How long does it take for the body to absorb the CO2 or N2O after a pneumoperitoneograph? Room air?
What can using room air for a pneumoperitoneography cause?
How do we prep a patient for a pneumoperitoneography?
same as for an upper GI series
Do we anesthetize the patient for a pneumoperitoneography?
Where is the injection site for a pneumoperitonegraphy?
halfway between umbilicus and pubis
Where do we do the surgical prep for a pneumoperitonegraphy?
halfway between umbilicus and pubis
How do we know when to stop injecting the contrast agent for a pneumoperitonegraph?
infuse gas until dull thud or bongo drum sound is produced on percussion
Why do we need to monitor a patient more carefully when doing a pneumoperitonegraph?
pressure of gas will make breaking more difficult so we need to watch respiratory rate and color of the patient
What are some other contrast procedures that are less commonly done in veterinary practices?
What is an angiography?
injection of iodine into blood vessel
What is an angiocardiography?
injection of iodine through the heart
What is cholecystography?
IV contrast material is excreted by liver
What does a cholecystography examine?
- gall bladder
- bile ducts
What is a bronchography?
infuse positive contrast material into airways to evaluate trachea and bronchial tree
What is a dacryocystorhinography?
injection of positive contrast material into nasolacrimal (tear) duct
What does a dacryocystorhinograph evaluate?
What is a sialography?
retrograde injection of positive contrast material into salivary duct to check salivary glands and duct
What are fistulographys and sinus tract infections?
positive contrast material may be injected into fistulous tract or sinus cavity
What is a fistula?
abnormal connection between two parts of the body
What are air bronchograms?
pathological lung densities outline bronchi
What is emphysema?
pathological accumulation of air in tissue or organs
What can emphysema be due to?
- tracheal ruptures
What is pneumothorax due to?
penetrating wounds, lung rupture
What is pneumomediastinum?
due to penetrating wounds
What is pneumoperitoneum due to?
penetrating wounds, bladder rupture
What is gastric dilatation and volvulus? What causes this?
- accumulation of gas in stomach
- torsion, pyloric problems, neoplasia, fermentation of food
What is ileus?
gas accumulation in intestines after peristalsis has stopped
What does ileus do to the bowel loops?