Angiography Flashcards Preview

MI > Angiography > Flashcards

Flashcards in Angiography Deck (17)
Loading flashcards...
1
Q

what is angiography?

A

angiography is way of imaging BVs or organs within the body

2
Q

what is DSA?

A

it digital subtraction angiography in which there is removal of unwanted portions of image (soft tissue) and leaving the relevant parts (vessels)

3
Q

Explain the process involved in DSA?

A
  1. Catheter insertion and placed at the right place
  2. test injection with small amount of contrast to confirm the catheter positioning in area to be images under fluoroscopy
  3. series of radiographs taken in which first mask image is acquired followed by a series of images
  4. Mask image automatically subtracted from the subsequent images and resulting image viewed in real time
  5. Series reviewed by radiologist to decide the diagnosis and end diagnosis, whether further series need to be taken of arterial supply and whether intervention procedure needs to be undertaken
4
Q

name six interventional radiography

A
  1. Angioplasty
  2. Stenting
  3. IV filters
  4. Thrombus and thrombolytic treatment
  5. Embolisation using quils or gels
  6. Ablation
5
Q

what is AVM?

A

AVM - malfunctioning b/w artery and vein system

6
Q

explain angioplasty procedure

A
  • After diagnostic procure, another catheter is inserted
  • A ballon is attached to the catheter and is placed across the stenosis (caused by the build up of plaques across arteries)
  • The ballon is infected leading to expansion of arteries and results in improved blood flow. however, the plaque is not removed
  • Angioplasty catheter consists of a gauge to ensure the ballon does not burst and different length and width of ballon to be appropriate for the stenosis size
  • A short procedure, patient does not need to go theatre however, there are risks as well
7
Q

explain the stenting procedure

A
  • Of the vessels is too weak and needs more than a ballon insertion then we can do stent insertion
  • Stent is a metal scaffold that supports the blood vessels
    1. A guide wire with a deflated ballon is passed through the catheter in narrow artery
    1. The ballon is then inflated to open the artery and the stent expands around the ballon
    1. The ballon is then removed and the stent in left in place to keep the artery open
  • This is a permanent opening and done for patients with weak vessels or when stenosis is severe
  • Lilac artery occlusions stetted to reduce the risk of distal embolisation
  • Renal artery stenosis - stetted rather than angioplasty because of elastic recoil of vessels
8
Q

explain thrombolysis procedure

A
  • For some occluded vessels
  • Infusion of anti-thromoblytic drugs/ anti-coagulation drugs e.g. streptokinase, urokinase
  • Different protocols used
    1. Low dose infusion (over a period of time)
    1. Bolus followed by low dose infusion
    1. Bolus followed by high dose infusion
9
Q

when is embolisms used?

A
  • Used for occluding vessels for
    1. Vessels supplying a tumour
    1. Vessels supplying an AVM
    1. Vessels supplying an aneurysm
    1. To stop internal bleeding
10
Q

what are the 3 types of emobilsation?

A
    1. Coils - permanent insertion into the patient, used for barricade stent
    1. PVA (polyvinyl alcohol particles) - permanent, medical version of super glue, need to make sure they applied in the right place. If applied in wrong place, it can occlude the vessels. Used to treat varicose veins.
    1. Gel foam - temporary, used when there is a bleed until the vessel can heal itself
11
Q

explain when and how vena cava filter is used?

A
  • Used for calcified veins or plaques
  • Inserted into the inferior vena cava
  • If any particle or plaque is loose within blood stream, gets trapped in the filter therefore, cannot enter the pulmonary system or heart and prevent occlusion in heart and embolism in lungs
  • The filter prevents the emboli from the lower limbs reaching the pulmonary circulation
  • May be permanent or temporary
  • Used when patient have
    1. recurrent pulmonary embolism (PE) despite the adequate anticoagulation
  • Or 2. PE when the patient cannot have anticoagulation
12
Q

what is ablation?

A

Ablation

  • Kill off unwanted tissues wherever that may be
  • Often cardiac ablation in heart for patients with erythema
13
Q

what are the three types of ablation used and in which cases?

A
  1. Radiofrequency - most commonly used, where high frequency radio waves is used to kill off tissues. Used for patients suffering from high menstural cycle to kill off the endometrium by inserting the catheter. However, cannot be perfumed for women who want to gt pregnant as RF ablation prevents the feotus to be viable
  2. Hydrothermal - heating of tissue
  3. Cryoablation - freezing of tissue, used in killing off tumour cells usually, cranial tumours. Catheter is inserted under fluoroscopy and once we know its in place, a lot of nitrogen is been sent to kill off the tissue by freezing it
14
Q

what are advantages and disadcnatges of CTA?

A

Advantage of CTA
- Look at vessels in more detail
- Can construct 3D images where as CATH in 2D
Disadvantage of CTA
- If any occlusion or stenosis is seen, they need to go into CATH lab for intervention

15
Q

what is digital subtraction angiography?

A
  • it is used in fluoroscopy imaging

- the contrast outline structure is highlighted by removing the background anatomical structures from the images.

16
Q

outline the steps involved in DSA?

A
  1. Acquire mask image (IM) to record anatomical background
  2. Contrast injected - Series of images acquired which show arrival and run-off of contrast (contrast medium enhanced image, IC)
  3. Image frames subtracted via digital processor. Any structures that are common to set 1 and set 2 are subtracted (i.e. all background anatomy but not the contrast filled structures)
  4. Amplify contrast signal to boost displayed contrast of the vessels
17
Q

what are the artefacts in DSA?

A

most common is misregistration