How to Read an MRI (Video)

MRI is a challenging thing to learn to understand but let’s try together.  Both the video tutorial above and the text below will help teach you how to look at your own MRI.

As you may know, an MRI scan is a method of taking pictures of the inside of your body using a magnetic field – there is no radiation.  The magnetic field interacts with the particles in your body to create detailed images of everything from the brain to heart to muscle.

Images were taken in three different views or orientations to try to get a 360-degree picture of you.  There is the sagittal or side view, the coronal or front view, and the axial or cross-sectional view.

The coronal view is similar to a mirror image in that the right side of your body will be on the left side of the image.  The axial view will also have the right side of your body on the left side of the image because the images are taken from the feet to the head.

Images are taken in small bits called slices.  Each slice has a thin width but covers the whole area in each particular view.  The width can be varied depending upon how strong the magnetic field is and how detailed an image needs to be – these parameters are optimized by your radiologist so no need to worry.

These slides are taken as shown in each view to create a stack of slices that is called a series of slices.  These slices are what you are looking at when you move your mouse, scroll the mouse wheel, or use the arrows keys and see the images moving.  They will “flow” through the stacks of slices in whichever view you are looking at to go from one side to the other.

For example, from front-to-back and back-to-front when looking in the coronal or frontal view.

Finally, the way the magnetic field interacts with you or the way the images are taken can be changed to give radiologists a slightly different perspective of the same view of images. The way that the magnetic field interacts with a part of the body is called the intensity.

For example, in most sequences, the soft tissue organs are gray in color and considered “isointense.”  Something that is bright (more white) will be called hyperintense and something that is darker (more black) will be called hypointense.

Sequences have specific names and provide certain types of value.  Some common examples include:

• T1-weighted images/sequence: good for looking at the “anatomy” of the body. The more “water” something has, the more “black” it looks.  Organs are gray or isointense.
  • Common colors of body parts:
    • Cerebrospinal fluid, cysts, swelling/edema, bone bruises: black
    • Fat: white
    • Organs, muscle: gray
    • Bone edges, lung: black

• T2-weighted images/sequence: good for looking at the “pathology” of the body.  The more “water” something has, the more “white” it looks.  Organs are gray or isointense. Tumors, swelling, bruising, and infections are usually bright and stand out.
  • Common colors of body parts:
    • Cerebrospinal fluid, cysts, swelling/edema, bone bruises, fat: white
    • Organs, muscle: gray
    • Bone edges, lung: black

• STIR images/sequence: makes all the fat dark or black to help see everything else better, especially fluid, infection, and injuries
• FLAIR images/sequence: makes all of the water and cerebrospinal fluid black and helps show brain diseases as bright
• Fat-saturated images: any sequence can have fat saturation (usually called fat sat or FS) which will make the fat black.

As we mentioned, MRI can be difficult and confusing.  Thankfully, our expert radiologists at Mediphany can help you understand your MRI.  If you’d like your images explained to you in a personalized video report, click here.