When and why

Magnetic resonance imaging (MRI) is used to examine many different body parts including the brain, the heart, arteries and other organs, and the musculoskeletal system and joints. Magnetic energy and radio waves create cross-sectional images or slices of the human body, providing fine details between different tissues with similar densities.

In HIV infection, may be used to examine the body following body fat changes also known as lipodystrophy.

If blood flow to an organ is thought to be impaired, a 'perfusion MRI' may be conducted. For example, a perfusion MRI can detect abnormalities in blood flow in the brain, which may be associated with HIV dementia, without the need for nuclear medicine techniques.

What's involved?

If you have metal implants from previous surgery, you may not be able to have an MRI. All jewellery and other metal objects must be removed before the MRI. Often a liquid is administered to the skin to heighten the contrast detected by the MRI.

When having an MRI, you are placed in a large tube-shaped or cylindrical magnet for between ten minutes and a couple of hours. New, open design MRI systems are sometimes available.

How it will help

In HIV, MRI may be used in a clinical trial investigating lipodystrophy, or in clinical practice to determine the nature of a person's weight gain or weight loss. This data will inform an appropriate treatment response.

MRI may also be used to detect early signs of HIV dementia and for monitoring the effects of therapy on the brain.