Imaging Circulatory Disturbances Flashcards
What imaging techniques are used to look at anatomy?
- Plain films
- Contrast angiography
- Ultrasound
- CT/MRI
What imaging techniques are used to look at function?
- Radionuclide imaging
- MRI functional imaging
- Ultrasound
What problems can vascular imaging look at?
- Soft tissue contrast
- Functional significance of lesions
- Is treatment effective
Density scale
Least dense 1. Air 2. Fat 3. Soft tissue 4. Bone 5. Metal Most dense
What are the ideal properties of a man made contrast agent?
- Inert
- Painless
- Easy to use
What structures often can’t be seen very well?
- Blood vessels
- Lumen of hollow viscera
What are the properties of iodinated contrast?
- Differential X-ray attenuation
- Inert
- Stable in selected body compartments
- Painless
- Easy to use
- Cheap
What are the problems associated with iodinated contrast?
- Major reactions
- Renal dysfunction
- Disturbance of thyroid metabolism
- Disturbances of clotting
- Seizures
- pulmonary oedema
What are the problems associated with parenteral iodinated contrast?
- Metallic taste
- Feeling of warmth
- Arterial injection causing micturition and discomfort
- Rarely nausea
What should be discussed with the patient before administering parenteral iodinated contrast?
- Previous contrast allergy
- Asthma/atopy
- Poor renal function
What drug is important to remember about when administering parenteral iodinated contrast?
Metformin
Why should metformin and parenteral iodinated contrast not be mixed?
Metformin can cross react with agents and induce renal failure
How is catheter angiography carried out?
- Vessel punctured and catheterised
- Contrast injected using pump injector
- Rapid series of images acquired
- Sterile procedure
Give examples of procedures classed as interventional radiology.
- Angiography/angioplasty
- Embolisation
- Catheter thrombolysis
- Drainage of abscesses
- Nephrostomy
- Vertebroplasty
When should angioplasty be used?
- Short stenosis or occlusions
- Sessile/ concentric plaques
- Iliac> sfa > popliteal> crural
What type of agent is carbon dioxide?
Negative contrast agent
When is carbon dioxide useful as a contrast agent?
Useful in patients with poor renal function or sensitivity to iodinated contrast agents
What problems can angioplasty cause?
- Occlusion
- Dissection
- Embolisation
- Rupture
- Infection
What are the properties of ultrasound?
- No radiation dose
- Quick
- Non invasive
- Resolution vs penetration
- May be more physiological
- Operator dependent
How does a normal vein present on ultrasound?
Normal vein has low pressure and is compressible
How does DVT present on ultrasound?
Vein is full of thrombus and is not compressible
Give examples of applications of radionuclide imaging.
- Perfusion
- Blood loss
- Sequential imaging
- Perfusion of transplanted kidneys
- Blood loss into GI tract
What are the advantages of nuclear medicine?
- IV injection only
- Good patient compliance
- Easy to arrange
What are the disadvantages of nuclear medicine?
- Radiation dose
- Very insensitive
- Very non-specific
