Contrast Flashcards
What is its imaging application?
- diagnostic CT
- MRI
- PET
- 4DCT
What is contrast media?
- radiopaque substances
- administered during medical imaging
- enahnce visualisation of organs
What is IV contrast media?
- administered intravenously
- injected through vein, flows through bloodstream, travels through arteries and viens
- CT, Flouroscopy, MRI
- enhances soft tissue deliniation
What are the phases of contrast media?
- arterial phase: 35-40 seconds shows arteries
- hepatic/portal phase: 70-80 secs shows hepatic and portal veins
- brain: 5 mins due to blood brain barrier
What is the contrast flow rate?
- dependent on volume of contrast administered
- patient weight increases = increased contrast = increased flow rate
- unit for flow is mL/sec
What are the ineligibility criteria?
- known allergy to contrast
- abnormal renal function (renal function assessed at least 1 month prior to planning) eGFR<45
- diabetes managed with metformin (need to be off this for 2 weeks prior to contrast)
What are some patient risk factors?
- congestive heart failure
- nephrotic syndrome
- dehydration
- multiple myeloma
- asthma
- hyperthyroidism
- myasthenia gravis
- sickle cell anaemia
- polycythemia and myeloma
- extremely anxious patients
- pregnancy/breast feeding
What is the post contrast allergies?
- dizziness
- nausea/vomitting
- itching/hives
- abdominal pains/muscle cramps
- anaphylactic reaction
What is extravasation?
- is the leakage of an intravenous drug from the vein into the surrounding tissue
- incident rate of 0.1-0.4%
What is the immediate treatment of extravasation?
- stop infusion and aspirate and revome cannula
- elevate effected extremity above heart
- apply hot pack wih towel
How can you prevent extravasation?
- flush the line with saline prior to injection of contrast
What site ustilise contrast?
- lung
- oesophagus
- mediastinal nodes
- liver
- pancreas
- metastatic brain lesion
Why is contrast kept at 37 degrees?
- as it can turn viscous which doesnt inject well
What is the type of intravenous contrast?
- iodine based non-ionic chemical
- OPTIRAY 350 pre-loaded syringes (100mL or 125mL)
- single barrel injector system
What are the risks and precautions with contrast?
- drug reactions: resuscitation trolley and adrenaline shot kept close
- staff trained and equipped: all basic life support, RO advanced life support
- multidisciplancy approach to preparation
- managment to pre and post procedure
What is the role of the RO?
- initial consent
- renal function test
- patient educaiton
- allergies
- consent for procedure
- discussion of cannula site with planner - CT SIM
- attach cannula
- start pressure injector
- monitor patient
- disconnect tubbing
- flush line with saline
What is the role of the nurse?
- remind patient to be well hydrated
- renal function test complete
- resuscitation equipment
- patient education
- remove cannula 20mins post CT
What is the role of the RT?
- ensure incubator is one and set to 37
- contrast is in incubator
- record contrast expiry date
- record contrast lot number
- record amount mL
- record on assessment form
- set flow rate on injector as per protocol
Contrast Reactions
Mild contrast media reactions include flushing, nausea, pruritus,
vomiting, headache and mild urticaria. They are usually self-limited and
resolve without specific treatment. Such may be seen in up to 1% of
patients after non-ionic low-osmolality contrast media administration.
• Moderate contrast media reactions include severe vomiting, marked
urticaria, bronchospasm or other respiratory symptoms, facial/laryngeal
oedema and vasovagal attacks.
• Severe contrast media reactions include hypovolaemic shock,
respiratory arrest, cardiac arrest and convulsions.
IV Contrast used in CT Simulation
Depends on treatment intent • Depends on treatment site • Patient eligibility criteria • Enhance tumour visualization • Improves target volume delineation • Minimise dose to critical structures
Smaller PTV margins with contrast
