X-ray vs MRI vs CT scan: Diagnostic scans explained

If a health concern needs further investigation, diagnostic scans can play an important role in helping healthcare professionals understand what's happening inside the body. From identifying broken bones and detecting injuries to investigating ongoing symptoms, different types of scans are used for different purposes.

X-rays, MRI scans, and CT scans are very different: X-rays are typically quick and used for bones, CT scans provide fast and detailed cross-sectional images using radiation, and MRIs offer highly detailed images of soft tissues without using radiation.

However, there are many further differences between X-ray, MRI, and CT scans, such as their costs, methods, and how long they take. Read on for our full guide on what these scans do, which one might be best suited to you, and how they can help your health.

How can I get immediate help with X-ray, MRI, or CT scans?

X-rays, MRIs or CT scans are generally suggested when it’s difficult to pinpoint the root cause of a health problem. These medical diagnostic scans involve specialist machinery and require a specialist to interpret the findings, meaning these scans can have very long waiting lists.

If you've had a Benenden Health membership for over 6 months, you can request support through our Medical Diagnostics service, including diagnostic scans, if the NHS wait is longer than 3 weeks. 

X-rays

What is an X-ray used for?

​X-rays are one of the most commonly used diagnostic tools. They use a small amount of radiation to produce images of the inside of the body, particularly dense structures like bones.

X-rays are typically used to:

• Diagnose fractures and broken bones.

• Check for joint problems.

• Identify chest conditions, such as pneumonia.

• Detect certain dental health issues.

They are usually quick, widely available, and often used as a first step before more detailed imaging is recommended.

Because X-rays provide less detailed images than CT or MRI scans, further tests may sometimes be needed to confirm a diagnosis.

What happens during an X-ray?

During an X-ray, a radiographer will position the part of your body being examined in front of the imaging machine. You may be asked to stand, sit, or lie down depending on the area being scanned.

The process is painless and usually only takes a few minutes. You’ll need to stay still briefly while the image is taken.

What to expect after an X-ray

Most people can return to normal activities immediately after an X-ray.

A specialist will review your images and send a report to your GP or referring clinician, who will discuss the results and any next steps with you.

Are X-rays safe?

Yes. X-rays use a low dose of radiation, and the benefits of diagnosing a condition generally outweigh the risks.

The radiation dose is carefully controlled, and exposure is kept as low as possible.

CT scan

What is a CT scan used for?

A CT (Computed Tomography) scan uses X-rays combined with computer processing to create detailed cross-sectional images of the body.

These images can show bones, organs, and blood vessels in much greater detail than a standard X-ray.

Most commonly, CT scans are used to:

• Assess injuries after trauma, or common household accidents.

• Detect conditions such as cancer, infections, or internal bleeding.

• Examine areas like the chest, abdomen, and brain.

• Identify blood clots or problems with blood vessels.

• Guide certain procedures, such as biopsies.

One of the main advantages of a CT scan is speed. Scans can often be completed within minutes, which makes them particularly useful in emergency situations.

However, CT scans involve higher radiation doses than standard X-rays because they take multiple images to build a detailed picture.

You may also hear people compare a PET scan vs CT scan, as both are used to help diagnose conditions inside the body. However, a PET scan focuses more on how tissues and organs are functioning, while a CT scan provides detailed structural images.

What happens during a CT scan?

You’ll usually lie on a motorised bed that moves slowly through a doughnut-shaped scanner.

You may be asked to hold your breath briefly during parts of the scan. In some cases, a contrast dye may be used to make certain tissues or blood vessels easier to see.

What to expect after a CT scan

If no contrast dye was used, you can usually leave immediately and continue your day as normal.

If contrast dye was used, you may be asked to wait briefly so staff can ensure you feel well enough before leaving.

Are CT scans safe?

CT scans are generally very safe, but they do involve more radiation than a standard X-ray because multiple images are taken.

Your healthcare team will only recommend one if they feel that the benefits outweigh the risks.

MRI scan

What is an MRI scan used for?

MRI (Magnetic Resonance Imaging) uses strong magnetic fields and radio waves to produce detailed images of the inside of the body. Unlike X-rays and CT scans, MRI does not use radiation.

MRI scans are especially useful for examining soft tissues, including:

• The brain and spinal cord.

• Muscles.

• Tendon and ligament damage, including ligament tears.

• Any issues with joints, including those caused by insufficient joint care.

• Organs such as the liver, kidneys, and heart.

Because of the level of detail they provide, MRIs are often used to investigate ongoing or complex conditions, such as neurological disorders or joint problems.

Since both MRIs and CT scans produce detailed internal images, many people ask about the difference between MRI and CT scan procedures. MRI scans are generally better for soft tissue detail, whereas CT scans are often preferred for speed and for assessing injuries or conditions affecting bones and internal bleeding.

MRI scans can take longer than CT scans, often between 15 and 60 minutes, and require you to lie still inside a scanner. This can feel uncomfortable for some people, particularly those who are claustrophobic.

What happens during an MRI scan?

You’ll lie on a bed that slides into the MRI scanner.

The machine can be noisy, so you may be given ear protection. You’ll need to lie still throughout the scan, which can last between 15 and 60 minutes.

What to expect after an MRI scan

Most people can return to normal activities immediately after their scan.

Your images will be reviewed by a specialist, and your GP or clinician will receive the results. Depending on the issue identified, your GP may refer you to another service, such as physiotherapy if you have joint issues.

Are MRI scans safe?

Yes, MRI scans don’t use radiation.

However, because it uses strong magnets, it may not be suitable for people with certain implants or medical devices. You’ll also need to remove metal items before the scan.

The main differences between X-rays, CT scans, and MRI scans

You may still be wondering about the difference between MRI and CT scan imaging. In simple terms, CT scans are often faster and better for emergencies, while MRIs provide more detailed soft tissue imaging without radiation.

Which scan is better: X-ray, CT scan or MRI scan?

Many patients ask, which is better CT scan, MRI, or X-ray? The answer depends entirely on your symptoms and what your doctor needs to investigate.

There isn’t a single “best” scan, as each one is designed for a specific purpose.

• X-rays are usually the first step for simple issues, especially involving bones.

• CT scans are often used when speed is important or when more detailed images are needed quickly.

• MRI scans are typically chosen for investigating soft tissue, neurological, or long-term conditions.

You might also still be wondering, is MRI same as CT scan? While they can sometimes be used to investigate similar symptoms, they provide different types of information and are chosen based on what your doctor needs to see.

Your doctor will consider several factors when recommending a scan, including:

• Your symptoms.
• Your medical history.
• The area of the body being examined.
• How quickly results are needed.

How can Benenden Health help me with medical scans?

If you’re unsure which scan you might need, or you have concerns about a recommended test, speaking with a healthcare professional is always the best place to start. Your GP will be able to tell you why they’ve referred you for a certain scan and how they think it will help.

When it comes to the scan itself, remember, Benenden Health members can request access to private medical diagnostics services, including diagnostic scans.

Not a member yet? Learn more about services available to Benenden Health members or subscribe to our e-newsletter to keep up-to-date with the latest news from Benenden Health.