MR angiography with contrast uses a gadolinium-based agent as an injectable. The gadolinium is drawn to the magnetic field, which makes it easier to distinguish blood vessels from nearby tissue.
What is MR Angiography with Contrast?
MR angiography (MRA) with contrast is a technique involving 3D spoiled gradient-echo (GE) sequences, with the administration of gadolinium-based contrast agents (GBCA). It can be used to assess the blood vessels of almost any part of the body.
MRA with contrast is not affected by any of the flow-related phenomena like velocities, flow direction, turbulence, etc. With MRA with contrast, the vascular signal intensity is determined by the concentration of gadolinium within the blood vessels.
How is MR Angiography with Contrast performed?
A gadolinium-based contrast agent is injected intravenously, usually into a central catheter or antecubital vein. In an adult with normal renal function, about 20 ml of contrast is administered followed by a saline flush (“chaser”) of another 20-30 ml. The goal is to inject the contrast into the central circulation while clearing all contrast from the proximal veins.
The injection of contrast and saline is either performed
- By hand using two syringes and a stop-cock.
- With a single syringe loaded with (denser) gadolinium on the bottom and (lighter) saline on top.
- More commonly power injectors are employed that use two syringes remotely controlled from the scanner console.
Side effects/risks of MR Angiography with Contrast
MRA with contrast could cause those with kidney problems or renal disease to develop a painful and disfiguring disorder known as Nephrogenic Systemic Fibrosis or Nephrogenic Fibrosing Dermopathy. The progressive disease has no effective treatment options and could lead to dependence on a wheelchair, or even death.
Preparation before performing MR Angiography with Contrast
The doctor needs to be informed about any prior medical conditions, especially kidney disease, allergies, and asthma. You will be
- asked to remove any metal objects
- given a mild sedative to help you relax if you are claustrophobic.
Post-care after MR Angiography with Contrast
In case you were given a sedative,
- do not drive or take public transport.
- Have someone with you for 24 hours afterward.
- Do not operate machinery on the day of the scan.
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