MRI vs Ultrasound—when is MRI better?

Ultrasound uses sound waves to display moving images of organs, blood flow, and pregnancies in real-time, while MRI provides much more detailed images of soft tissues, joints, and the brain. MRI is often better when precision is needed for complex conditions.

Follow-up explanation

MRI and ultrasound are both non-invasive imaging techniques, but they are used in different ways:

Ultrasound is fast, widely available, and involves no radiation. It is ideal for monitoring pregnancies, assessing blood flow, or examining abdominal organs in real time. Depending on your condition, your doctor may suggest an Ultrasound or a Sonogram.
MRI offers far greater detail, especially for soft tissues, joints, the brain, and the spinal cord. It is preferred for diagnosing tumours, neurological issues, and musculoskeletal injuries.

For example, someone with persistent knee pain may start with an ultrasound to rule out simple tendon issues, but an MRI is often needed to see cartilage damage or ligament tears.

When to use each

MRI: best for brain and spine conditions, joint and ligament injuries, tumours, and detailed organ assessment.
Ultrasound: best for pregnancy monitoring, gallbladder and kidney checks, blood vessel flow (Doppler), and quick abdominal scans.

Safety

Both scans are safe and do not use ionising radiation. Ultrasound is typically the first choice for children and during pregnancy. MRI, while safe, may not be suitable for patients with certain implants (e.g., pacemakers or some metal clips).

Results

With GetScanned, both MRI and ultrasound results are reviewed by consultant radiologists and delivered securely online. MRI results are typically available within 2-5 working days, while ultrasound results are often processed more quickly.