Contrast

Question 1

What is its imaging application?

Answer 1

• diagnostic CT
• MRI
• PET
• 4DCT

Question 2

What is contrast media?

Answer 2

• radiopaque substances
• administered during medical imaging
• enahnce visualisation of organs

Question 3

What is IV contrast media?

Answer 3

• administered intravenously
• injected through vein, flows through bloodstream, travels through arteries and viens
• CT, Flouroscopy, MRI
• enhances soft tissue deliniation

Question 4

What are the phases of contrast media?

Answer 4

• 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

Question 5

What is the contrast flow rate?

Answer 5

• dependent on volume of contrast administered
• patient weight increases = increased contrast = increased flow rate
• unit for flow is mL/sec

Question 6

What are the ineligibility criteria?

Answer 6

• 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)

Question 7

What are some patient risk factors?

Answer 7

• congestive heart failure
• nephrotic syndrome
• dehydration
• multiple myeloma
• asthma
• hyperthyroidism
• myasthenia gravis
• sickle cell anaemia
• polycythemia and myeloma
• extremely anxious patients
• pregnancy/breast feeding

Question 8

What is the post contrast allergies?

Answer 8

• dizziness
• nausea/vomitting
• itching/hives
• abdominal pains/muscle cramps
• anaphylactic reaction

Question 9

What is extravasation?

Answer 9

• is the leakage of an intravenous drug from the vein into the surrounding tissue
• incident rate of 0.1-0.4%

Question 10

What is the immediate treatment of extravasation?

Answer 10

• stop infusion and aspirate and revome cannula
• elevate effected extremity above heart
• apply hot pack wih towel

Question 11

How can you prevent extravasation?

Answer 11

• flush the line with saline prior to injection of contrast

Question 12

What site ustilise contrast?

Answer 12

• lung
• oesophagus
• mediastinal nodes
• liver
• pancreas
• metastatic brain lesion

Question 13

Why is contrast kept at 37 degrees?

Answer 13

• as it can turn viscous which doesnt inject well

Question 14

What is the type of intravenous contrast?

Answer 14

• iodine based non-ionic chemical
• OPTIRAY 350 pre-loaded syringes (100mL or 125mL)
• single barrel injector system

Question 15

What are the risks and precautions with contrast?

Answer 15

• 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

Question 16

What is the role of the RO?

Answer 16

1. initial consent
   - renal function test
   - patient educaiton
   - allergies
   - consent for procedure
   - discussion of cannula site with planner
2. CT SIM
   - attach cannula
   - start pressure injector
   - monitor patient
   - disconnect tubbing
   - flush line with saline

Question 17

What is the role of the nurse?

Answer 17

• remind patient to be well hydrated
• renal function test complete
• resuscitation equipment
• patient education
• remove cannula 20mins post CT

Question 18

What is the role of the RT?

Answer 18

• 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

Question 19

Contrast Reactions

Answer 19

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.

Question 20

IV Contrast used in CT Simulation

Answer 20

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