Difference Between X-Ray, CT Scan and MRI

radiology x-ray ct mri

For certain medical conditions, getting a clear picture of the interior of the body is crucial. A diagnostic imaging test is normally undertaken in such circumstances. This provides a clear image of the condition affecting your internal organ(s) so that the doctor can prescribe the necessary treatment. 

Different types of imaging devices are used to get a picture of your internal organs. Three of the most common diagnostic tests are X-ray, CT scan, and MRI. What are the differences between these scans? Read on more to find out.

What is an X-ray? 

An X-ray is the most basic diagnostic test that provides a 2D image of the internal organ. Even if you require sophisticated scans, you will be asked to undergo an X-ray first. 

An X-ray makes use of a low level of radiation to create images of the inside of your body. When an X-ray passes through your body, bones and other dense material inside the body block the radiation, thus creating a white image on the film. By looking at the image, the doctor can make out whether there is any injury or damage to the internal organs. 

X-rays are mostly used for diagnosing:

  • Issues affecting the bone like dislocation, fracture, and degeneration
  • Tumours affecting any part of the body
  • Infections

An X-ray test takes a maximum of ten minutes for its completion. The result can either be printed on an X-ray film or transferred to a CD for computer viewing. 

What is a CT scan?

A CT scan is recommended if the doctor requires a clearer image of the internal organs. In a CT scan, more powerful radiation is applied to get a picture of your internal organs. It can provide a 360-degree view of the organ, which helps the doctor in making a more accurate diagnosis. In certain types of CT scans, a contrast dye may also be injected to see the body structures clearly. 

A CT scan provides a clear image of blood vessels, bones, and soft tissues of the body. It is mostly used to diagnose conditions like:

  • Cancer
  • Heart disease
  • Appendicitis
  • Musculoskeletal diseases

A CT scan machine resembles a big box with a tunnel in the centre. You will be asked to lie on a sliding table that slides in and out of the tunnel. The machine inside the tunnel takes a cross-section image of your body. The technician will sit in a separate room and view the result on a computer. 

A CT scan is more expensive than an x-ray and is prescribed only if needed. 

What is an MRI scan?

An MRI or Magnetic Resonance Imaging scan makes use of magnetic fields and radio waves to generate images of your body parts. Here, the image is viewed as slices or cross sections of the body part. The main difference of MRI scan from X-rays and CT scans is that it does not make use of any radiation. 

An MRI scan is usually prescribed to investigate:

  • Anomalies in the spine or brain
  • Tumours and cysts in different parts of the body
  • Injuries to joint, back and knee
  • Evaluate the pelvic area of women for fibroids or endometriosis
  • Problems with the heart

An MRI scanner is a huge machine with a sliding table attached to it. The patient is made to lie down on the table and is slowly moved inside the machine. Since the MRI scanner makes a loud noise, ear plugs will be provided to block out the sound. When the scanning is underway, the patient will be asked to lie still without moving as it can blur the image. 

What are the differences between X-ray and CT scan? 

X-ray is used to locate abnormalities in any part of the body like the bones. A CT scan is an advanced form of X-ray that is used to detect internal organ injuries much more precisely. X-rays may not show minute details of certain organs, which is possible with the help of a CT scan. 

Another major difference is that an X-ray image is two-dimensional, whereas a CT scan is a three-dimensional image. A CT scan takes cross sectional images of the body part from different angles. These are then placed together on a computer screen to get a 3D image.  

What are the differences between CT scan and MRI?

A CT scan machine makes use of radiation to create images. An MRI scan machine, on the other hand, makes use of powerful magnets and radio waves. Thus, you are not exposed to radiation in an MRI scan. 

Another major difference is that a CT scan creates an image in a matter of a few minutes like an X-ray. An MRI, on the other hand, takes at least 30 minutes. 

A CT scan is mostly used to undertake scanning of injuries in chest, abdomen and spine. An MRI is used to diagnose problems in the brain, spine and abdomen. 

Final Thought

Depending on your health condition, the doctor will prescribe an X-ray, CT scan or an MRI scan. X-ray is the basic form of imaging test which is normally performed before a CT scan or an MRI scan may be considered.

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