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The Difference Between MRIs and X-Rays

  • Dec 9 2022

Doctor preparing patient’s knee for an MRI

If you experience an injury or suffer from an ongoing condition, your doctor may need to perform various types of imaging to see what is going on inside your body. Two of the most common types of diagnostic imaging services performed are X-rays and MRIs. Although they share some similarities, there are differences between the two, and depending on the condition or the area being investigated, one type of imaging may be more helpful than the other. While your doctor will ultimately decide which diagnostic tools are most appropriate for your condition, it can be helpful to understand the options available and how they work.

What Is the Difference Between X-rays and MRIs?

Both MRIs and X-rays provide images of bones, organs, and other internal structures of the body. X-rays, which use radiation to produce images, are often used to get a better view of your bones, while MRIs are preferred for soft tissue images and don’t use any radiation.

 An X-ray of a patient’s shoulder

X-rays are one of the most commonly used and widely available diagnostic techniques. They are typically more affordable than MRIs and take less time. Even if a patient may require a more sophisticated diagnostic tool, later on, they will usually be given an X-ray first. X-ray machines are ideal for looking at bones and bone density, fluid in the lungs, and sometimes tumors. They produce a static, lateral view of the area being examined. 

X-rays do emit a mild to moderate level of radiation, so patients should not have too many X-rays and doctors and patients should consider whether a patient might be pregnant at the time of an X-ray, as it can cause harm to an unborn child.

MRIs (or magnetic resonance imaging technology) do not emit any radiation. MRIs are much more detailed than X-rays and usually produce a 3D image of the area being checked. An MRI can produce images of bones, but it is more difficult to diagnose bone density in an MRI. Although MRIs do a much better job at viewing softer, internal organs than X-rays, they are less commonly used to detect lung illnesses like pneumonia. MRI technology is sometimes unavailable in smaller clinics, and they also take longer to complete and cost more to perform than an X-ray.

How Do They Work?


X-rays use radiation to produce images of the inside of the body. When the radiation passes through the body, bones and other dense objects appear white on the finished image. When taking an X-ray, the part of the patient’s body that is being examined will be placed between an x-radiation source and photographic plates. The machine then emits electromagnetic waves (radiation) through the body, which reflect the internal structures of the subject on the exposed X-ray films.


A doctor reviewing an X-ray image of a patient’s knee

MRI scans use strong magnets and high-frequency pulses of radio waves to produce detailed pictures of internal structures inside the human brain and other parts of the human anatomy. Most MRI machines are big, cylindrical magnets. Inside the machine, the magnet temporarily aligns the molecules of your blood and body so they’re easier for doctors to see. Radio waves cause these atoms to align themselves into patterns, which are detected by magnetic fields. These patterns are then converted into cross-sectional MRI (magnetic resonance imaging) scans, similar to slices in a loaf of bread.

Why Are They Used?

X-rays are most often used to examine and detect disease in bone structures, degenerative conditions, fractures and dislocations, infections, and tumors. If necessary, they can also be used to examine internal organs, in which case the patient may be administered barium sulfate or iodine-based contrast media to help highlight the internal structures in an X-ray.

MRIs are best at evaluating joint abnormalities or traumatic injuries in joints such as torn cartilage, tendons, or ligaments. MRIs are also best for viewing disks in the spine or brain tissue. The images produced by an MRI can show soft tissues (such as muscles), bones, blood vessels, nerves, tumors, cysts, and fluid-filled spaces.

Are X-rays or MRIs Painful?

The process of receiving an MRI or x-ray is not painful, although, when dealing with an injury, it may be uncomfortable to remain still inside an MRI for an extended period of time. In most cases, you should be able to complete your x-ray or MRI with little to no pain.

In some cases, you may need to receive an MRI “with contrast”. MRIs with contrast are used when the doctor or radiologist needs to highlight certain tissues or blood vessels so they can be seen better and in more detail. In this type of procedure, a “contrast agent” (or special dye) will be injected before receiving your MRI. Besides the “pinch” of the injection, there should be no pain. A small number of patients have reported mild rashes and pain at the injection site after receiving the injection, but the reactions usually do not last very long.

What Conditions Require an X-ray?

X-rays are best for viewing the following types of conditions:

  • Bone fractures
  • Bone density loss
  • Foreign objects in the body
  • Tumors in the lungs
  • Pneumonia in the lungs

What Conditions Require an MRI?

MRIs are best at examining the following conditions:

  • Tumors or signs of stroke in the brain
  • Nerve damage
  • Muscle damage
  • Ligament damage
  • Abnormalities in tendons

What Are the Pros and Cons of Each Test?

When weighing the pros and cons of each test, the following should be considered:

  • Availability: Does your local imaging facility or hospital offer MRIs? X-rays tend to be more readily available.
  • Cost: If paying out of pocket, MRIs are usually more expensive than X-rays.
  • Time: MRIs can take anywhere from 15 minutes to 2 hours to complete, whereas X-rays take seconds.
  • Safety: If you are pregnant, precautions should be taken before getting an X-ray. However, MRIs produce no radiation and are safe during pregnancy.
  • Bone or no bone?: If you are trying to create a detailed image of a bone, X-rays are best. MRIs are best for softer tissue.

Which Test Is Right for You?

The condition you’re being examined for will determine which type of diagnostic testing is best for you. Although X-rays do pose a small amount of risk because of the radiation being emitted, they are still useful in many settings, and the benefits of an X-ray generally outweigh the risks when compared to an MRI.

To learn more about which type of imaging is right for you, contact the professionals at SI Ortho. Our experienced team of orthopedic physicians will expertly examine and diagnose your condition, and we are affiliated with some of the top hospitals across Long Island. We also offer orthopedic urgent care locations that are available nearby when you need them most. Schedule an appointment today!

Posted in: X-rays