40. Imaging of Circulatory Disturbances

Question 1

What to look for in vascular imaging? (4)

Answer 1

1. what is the anatomy?
2. is there a leak?
3. is there a blockage? (occlusion or stenosis?)
4. can it be fixed

Question 2

What are anatomical vascular imaging techniques? (4)

Answer 2

1. plain films
2. contrast angiography
3. ultrasound
4. CT/MRI

Question 3

What are functional vascular imaging techniques? (3)

Answer 3

1. radionuclide imaging
2. MRI functional imaging
3. ultrasound

Question 4

What do we look for in vascular imaging? (3)

Answer 4

1. soft tissue contrast?
2. functional significance of lesions
3. is treatment effective?

Question 5

From bone, metal, soft tissue e.g. muscle, fat and air, name them from most to least dense.

Answer 5

1. metal (most dense)
2. bone
3. soft tissue e.g. muscle
4. fat
5. air

Question 6

What are the ideal properties of a man-made contrast agent used in radiology? e.g. iodinated contrast (6)

Answer 6

1. has attenuation different as the surrounding tissues (ability for a structure to weaken and soak up x rays = attenuation), differential x ray attenuation
2. inert (chemically inactive)
3. not equal distribution in and out of selected body compartments (stable in selected body compartments)
4. painless
5. easy to use
6. cheap

Question 7

What are problems with iodinated contrast? (6)

Answer 7

1. major reactions can occur
2. renal dysfunction (since big macromolecules found within iodine)
3. disfunction of thyroid metabolism (if under active)
4. disturbance of clotting
5. seizures
6. pulmonary oedema

Question 8

What are side effects of paranteral (through IV) iodinated contrast? (4)

Answer 8

1. metallic taste
2. feeling of warmth
3. arterial injections: micturition, discomfort
4. rarely nausea

Question 9

What always needs to be discussed with patient and evaluated prior to paranteral iodinated contrast is administered?

Answer 9

1. previous contrast allergies
2. asthma/atopy (genetic tendency to develop conditions)
3. poor renal function; nephropathy can be a problem
4. ALWAYS ask if patient is on Meformin for diabetes (SERIOUS reaction can occur)

Question 10

What happens during catheter angiography?

Answer 10

• vessel is punctured and catherised (catheter inserted into skin through vessel)
• sterile procedure
• iodine contrast injected using pump injector
• rapid series of images taken

Question 11

What are some interventional radiology procedures which are minimally invasive treatments? (6)

Answer 11

1. angiography/ angioplasty
2. embolisation
3. catheter thrombolysis
4. drainage of abscesses
5. nephrostomy
6. vertebroplasty

Question 12

When to use angioplasty?

Answer 12

1. short stenoses or occlusions
2. sessile/concentric plaques
3. iliac> s.femoral artery> popliteal > crural
   The bigger the vessel, the better the function result following angioplasty.

Question 13

What is the main benefit of angioplasty?

Answer 13

Not as dangerous as surgery (however its effects not as long lasting)

Question 14

What is inserted mainly though angioplasty?

Answer 14

Stents: to restore blood flow to the vessel

Question 15

What is an example of a negative contrast agent?

Answer 15

carbon dioxide

Question 16

When is CO2 used as contrast agent? (2)

Answer 16

• if patient has poor renal function

- if patient is sensitive to iodinated contrast agents

Question 17

What is an example of a positive contrast agent?

Answer 17

iodine

Question 18

What is angioplasty used for? (5)

Answer 18

1. occlusion
2. dissection
3. embolisation
4. rupture
5. infection

Question 19

What are main pros for ultrasound use? (6)

Answer 19

• no radiation dose
• quick
• non-invasive
• resolution vs penetration
• good for physiological findings
• operator dependent

Question 20

On an ultrasound probe, when does image appear red and when does it appear blue?

Answer 20

Red; when blood flowing towards the probe

Blue: when blood is flowing away from the probe

Question 21

What is radionuclide imaging used for? (2)

Answer 21

• to check perfusion (and ventilation)
• to check blood loss
  (sequential imaging)

Question 22

What can be easily seen on a V:Q scan?

Answer 22

Pulmonary embolism (perfusion abnormal but ventilation is normal)

Question 23

For which conditions is radionuclide imaging beneficial for? (2)

Answer 23

• perfusion of transplant kidneys (or any organs)

- blood loss into GI tract

Question 24

What are pros for nuclear medicine? (3)

Answer 24

• IV injection only
• good patient compliance
• easy to arrange

Question 25

What are cons for nuclear medicine? (3)

Answer 25

• radiation dose
• very insensitive
• very non- specific

Question 26

What are pros or CT angiogram? (3)

Answer 26

• gives information about other structures
• sensitive
• IV injection only

Question 27

What are cons for CT angiogram? (3)

Answer 27

• radiation dose
• high contrast dose
• expensive

Question 28

What are pros for magnetic resonance angiography (MRA)? (4)

Answer 28

1. sensitive
2. specific
3. no radiation
4. no nephrotoxic contrast

Question 29

What are cons for magnetic resonance angiography? (3)

Answer 29

1. very expensive
2. needs state of the art machinery
3. high contrast cost

Question 30

Define consent in radiology.

Answer 30

A process in which a patient learns key facts about an investigation/ treatment, including potential risks and benefits, before deciding whether or not to proceed.
Informed consent continues throughout the procedure.

Question 31

Who should obtain consent for interventional radiology purposes?

Answer 31

• only the person doing the procedure

- new graduates should not obtain consent for procedures they don’t fully understand

Question 32

Who should not administer contrast media to patients?

Answer 32

Students/staff who cannot recognise and treat any potential reactions

Question 33

When can a newly qualified doctor gain informed consent from patients?

Answer 33

Only when they have detailed knowledge from active involvement and experience in interventional studies.