Like CT scans, MRI (Magnetic Resonance Imagery) shows soft tissue and bones in cross section. But MRI (unlike CT) doesn’t use radiation in the ordinary sense - instead it uses a combination of magnetic and radio waves. Because hydrogen atoms react to a magnetic field, a scan can be made and a computer used to analyse the results, giving ‘pictures’ of the inside of the body.
MRI can be used to investigate a range of foot and ankle conditions, including:
- Tendon, ligament and cartilage injuries
- Tumours (soft tissue and bone)
- Avascular necrosis
MRI and pregnancy
As MRI heats the body slightly, the technique is not commonly used during the first 3 months of pregnancy unless immediate diagnosis is required, and the only alternative is to use X-rays. Even after the first 3 months, the use of MRI is avoided if diagnosis can wait till the child is born.