Diagnostic imaging

Angiography

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Diagnostic angiography is a medical imaging modality used for the visualization of the inside or lumen of blood vessels, particularly the arteries, veins and the heart chambers. Contrast media is injected into the blood vessels for the study. It employs the use of x-rays. Angiography machines can either be conventional angiography or digital subtraction angiography. Digital subtraction angiography is the most commonly used. Currently, most of the procedures performed by angiography are replaced by computed tomography angiography or magnetic resonance angiography. It involves vascular puncture and introduction of guidewires and catheters.

Common clinical applications

  • Diagnosis of obstructive vascular diseases
  • Diagnosis of aneurisms particularly intracranial aneurism
  • Diagnosis of arterio-venous malformations
  • Diagnosis of bleeding vessels
  • Assessment of the vascularity of malignant tumours
  • Image guided interventional procedures

Safety

  • Procedural complications due to intervention such as haemorrhage, infection, shock, rarely death as a result of the procedure.
  • Hypersensitivity reaction to contrast agents may range in severity from flushing to anaphylaxis. Risk factors for immediate hypersensitivity reactions to IV contrast include previous allergic reaction to IV contrast, history of asthma or food allergies.
  • Patients with renal insufficiency/failure, multiple myeloma, severe cardiac disease such as congestive heart failure, aortic stenosis, should not receive IV contrast. Other examples include severe dehydration, diabetics and sickle cell disease.
  • As with plain radiography, angiography utilizes x-ray radiation to produce images, however the radiation doses from angiography are higher. Pregnancy status must be established prior to exam. X-ray procedures should be delayed until after pregnancy where possible or non radiation imaging such as ultrasound or MRI utilized.
  • As children are more radiosensitive, x-ray procedures should be performed with caution.