Angiography Flashcards
What is angiography
radiography of blood or lymph vessels, carried out after introduction of a radiopaque substance
Type of fluoroscopy- either diagnostic (looking for pathology) or interventional (carry out a procedure).
what is a query-proceed procedure
diagnostic procedure but have consented that if intervention is needed can be carried out.
What is Diagnostic Angiography
a procedure which physicians use to investigate abnormalities of the blood vessels.
For the procedure a catheter is placed in the selected blood vessel and contrast is administered while a rapid set of x-rays is obtained analogous to time lapsed photography.
What is DSA
Digital Subtraction Angiography (DSA)
- Digital – done by computer
- Subtraction – removal of unwanted portions of the image (leaving the relevant parts more easily seen)
- Angiography – Imaging of the arteries
Reversal of image, because black on white is psychologically easier to see. (We are used to seeing print as black letters on white paper.)
why do we use DSA
Better, clearer images of vasculature
What is DSA often used for
- Viability of a vessel prior to transplant*
- Suspected stenosis causing ischaemia- narrowing of vessels
- Suspected aneurysm, suspected AVM- arteriovenous malformations
- Patency of graft ^
- Trauma e.g. aortic rupture
Advantages of CE-MRA
- No radiation dose
- Gadolinium has less associated side effects than iodine-based contrast
- Less invasive – pump injection through vein in arm etc
Describe the interventional angiography procedure
- Put permanent puncture into femoral/brachial artery.
- Contrast to check going along correct route.
- Carry out intervention of choice
- Because puncturing artery- have angioseal on wound.
- Wound has to apply pressure to the wound for ~20 mins.
- Remain flat/bed rest for 4 hours post-intervention.
What are some common interventional radiography procedures
- Angioplasty
- Stenting
- IV filters
- Thrombosis
- Embolisation
- Ablation- uses heat
Describe the angioplasty procedure
- Catheter passed through with two dots either side of the stenosis
- Balloon blocks the artery, so inflation is timed and may be repeated several times.
Disadvantages of angioplasty
not always a permanent fix- if plaque is present, they will continue growing or may cause damage in the future.
Also, part of the plaque could break off- causing a stroke or PE as a vessel ends up being blocked.
What are the two basic parts of an angioplasty catheter
How do we know what size balloon / stent is required?
Measure from image
correct for magnification of image e.g. use coin or some other scale
What is a stent
Stent – metal scaffold that supports the vessel wall and remains rigid
Describe the stent fitting procedure
What is a stent-graft
- Repairs ruptured vessels (Including vessels ruptured during angioplasty!)
- Straight tubed / bifurcated
What is thrombolysis
Infusion of anti-coagulation drugs eg streptokinase, urokinase via catheter
i.e. for varicose veins or occlusions
What is the purpose of embolisation
For stopping vessels supplying something i.e.:
- Occluding vessels e.g.
- Vessels supplying a tumour
- Vessels supplying an AVM
- Vessels supplying a cerebral aneurysm
- To stop internal bleeding
What is an embolisation coil
Coils come in different shapes and sizes, but permanently in place. Although can move to some degree
What is an AVM
AVM
is an abnormal connection between arteries and veins, bypassing the capillary system.
What is a vena cava filter
- Prevent emboli from the lower limbs reaching the pulmonary circulation
- May be permanent or temporary
- Indications include:
- Recurrent PE despite adequate anticoagulation
- PE where the patient cannot have anticoagulation
