Contrast Media Flashcards
Why do we use contrast media
To visualise soft tissues
Gastrogram
+ve cm barium is used to line the organ and then distended with -ve cm air
Cystogram
+ve cm iodine is used to line the bladder and then distended with the negative cm air
Positive contrast media
contains elements of a high atomic number that are radio opaque (i.e. appear white on xray film - whiter than bone)
Negative contrast media
Gases which because of thier low density are radiolucent and appear black on x-ray. Commonly used gases, O2, room air, CO2,
Examples of common +VE contrast media
Barium
Water soluble iodine
Barium
Micropaque - powder, paste or solution
Used in GI tract
Adv - inert, insoluble
Dis- may cause a foreign body reaction if leaks
Water soluble iodine - Most common
Conray
Gastro-conray
Urografin
Gastrogafin
Hypaque
Water soluble iodine - Features
Hypertonic
Soluble
Following IV - excreted via kidney
Can use direct into lower urinary tract
Can use direct into GIT (not as effective as barium but can use if GI rupture)
Water soluble iodine- side effects
IV may cause fall in blood pressure or anaphylactic reaction
If animal conscious may cause whining or retching
Lower osmolar ionic media
e.g. Hexabrix
Fewer side effects than water soluble iodine
Better contrast in GIT than water soluble iodine
Not good for myelogram - draws water in and causes pressure
Lower osmolar non-ionic media
E.g. Omnipaque
Safe for myelography
Contrast radiography methods
Myelography
Gastrogram
Cystogram
Retrograde urography
IV urography
Myelography
Used to indicate lesions that are not detectable on ordinary x-rays
Indications- spinal pain, neurological signs, prolapsed invertebral discs
Myelography preperation of patient and equipment
Anaesthetised
Clip area (caudal to skull or lumbar spine)
Spinal needle (20-22g)
Warmed contrast media
Check dose ( variations between cisternal tap and lumbar tap)
Syringe
Sample bottle for CSF
Aid to elevate head
Surgical scrub
Sterile gloves
Myelography method of restraint
GA essential
Myelography method
Cisterna Magna puncture (most common for myelogram)
Lumbar puncture
Cisterna magna puncture method
Elevate table to about 10 degree of tilt
Clip and surgically clean site
Head flexed 90degrees to spine
VS inserts needle between skull and atlas vertebra
Advance needle slowly until CSF drips out
CSF for cytology analysis
inject warm contrast media slowly 1min
Patient must not move for injection/while spinal needle is in place
Needle removed and head extended again
Head to remain elevated until completely recovered
X-rays
Sequential lateral to follow media
VD when lesion identified
Same for lumbar puncture
Upper Gastrointestinal study
to evaluate the stomach and small intestines
Indicated for patients; V+ Abnormal bowel movements Suspected FB or obstruction Chronic weight loss Persistant abdominal pain
Upper Gastrointestinal study contrast media
Orally administered via stomach tube
Barium sulphate normally used (+ve CM)
Water soluble iodine to be used if intestinal perforation is suspected
both +ve and -ve contrast media can be used
Upper Gastrointestinal study equipment
Stomach tube
Large syringe
Water soluble iodine
Lubricant
Upper Gastrointestinal study patient preperation
Fast for 24 hours
Enema day before, 4hrs before and 1hour before
Sedate if necessary (suggested sedative ACP)
glucagon (GI hypotonic agent that induces hypomobility)
GA slows gut
Atropine slows gut
Upper Gastrointestinal study procedure
Survey radiographs to be taken
Administer barium (or water soluble iodine if suspect perforation)
Place contrast media using syring into patients mouth allowing to swallow OR orogastric tube
(small amount water infused to check placement - will couch if incorrectly placed)
Upper Gastrointestinal study radiographs to be taken
DV, VD, R lateral, L lateral
Take immediately after CM administration
Take at 15, 30, 60 and 90 minute intervals
Pneumocystography
Contrast media is air or gas such as carbon dioxide
Pneumocystography air/gas dosage
Small dogs/cats - 35ml
Larger dogs - 50 - 300ml
Pneumocystography precautions
Palpate bladder whilst administering gas to prevent rupture/ over distention
Patient to be placed in L lateral recumbency to administer - reduces risk of air embolism
Pneumocystography equipment
Urinary catheter 3 way tap syringes sterile lubricant sterile spray/germicidal soap prep gauze 2% lidocaine or GA/sedation sterile gloves otoscope speculum kidney dish
Pneumocystography patient preperation
Fasted 12-24hrs
Enema at least 4hrs prior to exam
Sedated/anaesthetised
Abdo imaging should be taken prior to sedation/GA
Pneumocystography procedure
R lat and VD views of abdomen
External areas cleaned w appropriate solution
sterile lubricant to catheter
Insert catheter aseptically
lidocain into bladder (dog 3-5ml, cat 2-5ml)
place in L lat recumbency
administer air or gas
Bladder palpated to avoid over distension
L lat, VD and oblique views of bladder
Double cystography contrast media
gas/air
water sol iodine
Double cystography precautions
(same as pneumocystogram)
Palpate bladder whilst administering gas to prevent rupture/ over distention
Patient to be placed in L lateral recumbency to administer - reduces risk of air embolism
Double cystography precautions
(same as pneumocystogram)
Palpate bladder whilst administering gas to prevent rupture/ over distention
Patient to be placed in L lateral recumbency to administer - reduces risk of air embolism
Double cystography equipment
Urinary catheter 3 way tap syringes sterile lubricant skin prep solution gauze 2% lidocaine sterile gloves Otoscope speculum Kidney dish Water sol iodine
Double cystography patient prep
Fasted 12-24hrs
Enema at least 4 hrs prior to exam
GA / sedation
Abdominal images should be taken prior to GA/sedation
Double cystography procedure
R lat and VD views of abdomen
External areas cleaned w appropriate solution
sterile lubricant to catheter
Insert catheter aseptically
lidocain into bladder (dog 3-5ml, cat 2-5ml)
place in L lat recumbency
administer air or gas
Bladder palpated to avoid over distension
L lat, VD and oblique views of bladder
Double cystography indications
Haematauria
Dysuria
Infection
Bladder rupture
Anuria
Calculi
Angiocardiography
congential/aquired cardiac disease
GA required
CM injected into jugular/cephalic vein
or directly into heart chambers via catheters into jugular vein and carotid/femoral arteries
Several radiographs taken
Portal venography
Liver disease
GA laparotomy perfomed and splenic or mesentric vein cannulated
Iodine CM is injected as a bolus
A normal liver will show the CM entering through the portal vein & through liver (branching)
Bronchography
Viscous iodine
Patient is anaesthetised and placed in lat recumbency with side to be investigated downwards
CM injected through ET tube
Will show parasites, FB an tumours
Arthrogrophy
-ve, +ve or double CM used
GA required as painful
Will show joint distension or rupture and defects in the joint cartilage
Most commonly used in the shoulder of the dog (1-1.5ml iodine) to demonstrate OCD
Fistulography
Will show up sinus tracts and fistulae using water soluble iodine
Used to show extent of damage and whether there are any foreign bodies
