How Does an MRI Scan Work

(STL.News) – MRIs or Magnetic resonance imaging is a form of nuclear medicine that scans your body to create a detailed image.  The scan utilizes a strong magnetic field along with radio waves to view images in more detail than a CT scan, X-ray or ultrasound.  If your doctor needs to see inside your muscles, ligaments, cartilage, tendons and joints, the MRI is the best method.

The MRI machine is used to diagnose internal body injuries.  This includes tumours, strokes, concussions, aneurysms, multiple sclerosis, spinal cord injuries, and inner ear and eye problems.  More specifically, you can use this method to view the internal structure of the brain.  It is however worth noting that a regular MRI cannot detect conditions which are not caused by structural damage to the brain, such as post-concussion syndrome.

What the Patient Can Expect

When you enter the room, a nurse or tech will ask you to lie on a table that will move you into an opening.  The MRI is open from both sides and will not enclose you completely.  The test doesn’t hurt, but you may feel an odd sensation through your body; you’ll suddenly feel hot.

One thing to be aware of is the loud thumping or tapping that happens when the machine starts to scan.  If this is too loud, a nurse will offer you headphones or earplugs to make you more comfortable.  You might be given an intravenous solution of liquid dye, but your nurse will inform you if this is needed.

Make sure not to move around while in the machine because it may interfere with the scan.  The scan itself may take a while, as the tech will want to take a lot of pictures. 30 to 60 minutes is the average time your test will take place.

How the MRI Machine Works

We’re mostly made of water, and those waters contain the molecules H2O, and the hydrogen nuclei protons align with a magnetic field.  MRIs use these protons to make them spin.  A radiofrequency is also used to create an opposite magnetic field.  Protons will absorb this energy and flip them while they spin.  When the protons gradually return to their normal spin, the process can be seen on the scanner.

Since different body tissue returns to average speeds at a different rate, the scanner can easily differentiate between body parts.  Diffusion MRI sees how molecules diffuse in the body, which is helpful to determine strokes or tumours.  Functional MRIs view function in the brain because it measures blood flow change.  This is helpful for evaluation head injury (concussions) or Alzheimer’s disease.  FMRIs are often used in neuroscience and have even led to breakthroughs in how we study the brain.