What is an MRI Scan & How Do MRI Machines Work?

What is an MRI Scan? How do MRI machines work? What does an MRI show? Physio Logic‘s Dr. Tanuj Palvia, MD answers these questions and discusses the changes in MRI machines over the years and what and how they’re used today.

Over my many years of practice, I have noted incredible advances in imaging capabilities in the medical field. This technology has come a long way, and in many instances, it can save lives.

One of the most popular modalities for imaging diagnostics is Magnetic Resonance Imaging or MRI. Today, physicians use this amazing technology to create detailed images of organs and tissues within your body.

In the orthopedic world, there is especially a great utility to magnetic resonance imaging in the diagnosis and treatment planning for a wide variety of conditions. If you’ve ever been hurt and have been prescribed an MRI by a physician, here’s what you should know about MRI scans and whether it would be helpful for your situation.


MRI machine

What is an MRI scan?

An MRI machine uses a large magnet combined with radio waves and computer technology to produce sliced images of the body’s internal organs and structures. This technology is non-invasive and does not emit radiation.

The scanner itself looks like a large tube. Patients lie on a table and slide into the machine. It’s important to remain still to create accurate cross-sectional images. Once the images are created, a radiologist views the images and uses the information to diagnose problems within the body.

A radiologist is a physician specializing in radiology, the branch of medicine that uses ionizing and nonionizing radiation for the diagnosis and treatment of disease. Like other physicians, a radiologist must have graduated from an accredited medical school, passed a licensing examination, and completed at least 5 years of graduate medical education, also known as residency. Radiologists are usually board-certified, which means they have taken and passed a standardized examination and thus are approved and credentialled to practice in the field of radiology by the American Board of Radiology.

MRI vs. CT scan: Which is right for you?

Both MRI and computed tomography (CT) scans create images of the body’s internal structures. Under certain circumstances, a CT scan is more appropriate than an MRI. A skilled physician can determine which imaging technology is best for your unique situation.

The primary difference between an MRI and a CT scan is that an MRI uses radio waves and a CT scan involves specialized X-ray technology. However, MRIs are better at visualizing certain body structures than CT scans.

An MRI is commonly warranted when there’s a need to view detailed images of soft tissues, such as cartilage and ligaments. MRI technology does this better than CT scans. This allows your physician to pick up problems that may be invisible using other imaging technology.

On the other hand, if your physician wants to check solid tissues, like bone, a CT scan is likely the preferred choice. For example, your doctor may order a CT scan to check for problems with your spine.

Some patients may want to choose an MRI over a CT scan simply because they wish to avoid radiation. It’s important to know that the benefits of getting a CT scan when appropriate outweigh the risks. Your physician will explain why one imaging technology is warranted over another in your case.

What can an MRI help diagnose?

A number of scenarios warrant getting an MRI. Your doctor may order a scan to help diagnose:

  • Tumors
  • Heart damage
  • Lung damage
  • Problems with your eyes or ears
  • Problems with your veins or arteries
  • Brain abnormalities, such as tumors, and dementia
  • Abdominal/digestive tract problems
  • Pelvic problems (in women) or prostate problems (in men)

In the interventional pain and orthopedic world, an MRI can help in diagnosing:

  • Sports injuries
  • Problems with your spine, including disc (rubbery cushions between your backbones) problems, arthritis, or spinal tumors
  • Bone diseases and conditions
  • Joint problems
  • Cartilage abnormalities
  • Cysts within your body
  • Problems with your spinal cord
  • Ligament / soft tissue disorders

These are just a few conditions where your physician may order an MRI.

What should you know about MRIs before getting one?

Some patients get anxious about having to slide into the tube of the MRI machine. If confined spaces cause you difficulties, discuss it with your physician. For example, in certain scenarios, I will order anti-anxiety medication to keep you relaxed while getting your MRI.

MRI machines use powerful magnets. Prior to scheduling your MRI, the staff will ensure that you can safely undergo this imaging. Patients with metal inside their bodies are usually unable to have an MRI. The clinical staff will go over everything in detail to ensure that you’re properly prepared for your MRI scan.

So, do I need an MRI?

It depends.

A lot of times, a diagnosis can be made without imaging! There are a number of physical exam maneuvers, in the context of a good history obtained, that can help narrow down and even nail down a diagnosis. In my expertise, sometimes we can undergo a treatment plan without obtaining imaging first. This is vastly dependent on the severity and acuity of presentation, and how clear or unclear the clinical scenario is, and whether it will affect the recommended plan.

For example, if there is only mild pain due to an overuse injury, responding to physical therapy and medical treatment, then is it necessary to obtain imaging if it will not change the treatment plan? Many times yes, but sometimes this might not be necessary. It is important to have a clear conversation with your physician to elucidate these goals and ascertain if additional imaging will help the overall treatment plan.

If you’re experiencing aches and pains and want to get a better understanding of what’s going on inside your body, contact our Interventional Orthopedics & Sports Medicine Department. Give us a call or you can start by filling out the form below.

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