Multiple Sclerosis Centers of Excellence
Understanding Your MRI Report
Yohance Allette, MD, PhD and Michelle Cameron, MD, PT, MCR
Magnetic resonance imaging (MRI) is an excellent resource for people with MS. MRI studies provide a safe and non-invasive way to obtain detailed images of the brain and spinal cord, without any radiation exposure.
As patient access to medical records continues to increase, patients can sometimes see the images or read the MRI report even before discussing them with their neurologist. This presents a challenge, since the language in the report and importance of certain findings, is not always easily understood by someone who isn’t trained to read them. It is best to review an MRI report with your physician, whether face-to-face or by telephone or webcam, to make sure that the radiology report is translated with your specific health and diagnosis in mind. If you are reading the MRI report on your own, there are key things to look for, and be prepared to sort through cumbersome medical terms.
An MRI is made by combining multiple images, with each image being an extremely thin slice of the brain or spinal cord. Some MRIs progress in the direction of the feet to the top of the head, which means on the computer screen the right side of the image is the left side of the body. Every MRI can be rearranged by computer to show different perspectives, providing even more information about potentially damaged brain tissue caused by MS.
Each MRI can also be taken in different formats, also known as sequences, like a filter in photography. Each sequence has its own advantages and disadvantages. T1 sequences show detailed anatomy of the brain and spinal cord, which is helpful to identify “black holes” which represent areas of atrophy or shrinking of previously injured brain tissue. These black holes can also be called “hypointense” on the MRI report. T2 MRI sequences are used to highlight areas of demyelination, which happens when the outer layer of the neurons is damaged due to MS activity. T2 sequences can be used to count the total number of MS lesions, which look like bright white spots on T2 sequences, and can be called “hyperintense”. To help identify new or active areas of disease, a special contrast dye can be given by IV during the MRI. This makes it easier to compare new MS activity, older injury, and healthy brain tissue. The contrast dye contains a metal called gadolinium, made non-toxic for medical use.
Altogether, T1 sequences show any old areas of atrophy or black holes, T2 sequences help show the overall number of MS lesions in the brain or spinal cord (a.k.a. “MS lesion burden”), and contrast-enhanced sequences show any new and active MS lesions (a.k.a. “enhancing lesions”).
Every MRI has a radiologist review the entire study very carefully, looking for both normal brain tissue and potential signs of disease. Sometimes an MRI reviewed by a radiologist can provide enough evidence to make a diagnosis. But in the case of MS, it takes a combination of the MRI with the patient’s clinical symptoms, history, and neurological examination to make the diagnosis. MS diagnosis involves meeting several clinical and imaging criteria, in addition to making sure no other disease can explain the patient’s presentation. In other words, the patient’s neurologist needs to look for signs of MS while making sure nothing else could explain the patient’s current condition at the same time.
While it is true that almost all people with MS will have evidence of brain lesions on MRI, not all people with brain lesions have MS. Therefore, an MRI report lists many possibilities that could explain the MRI’s particular appearance. This list of possibilities always requires thoughtful review by the patient’s health care provider and must always consider the broader picture.
An MRI alone cannot be used to see how well a patient is doing; it must always be studied with the patient in mind. An MRI cannot take the place of regular follow up visits, clear communication of symptoms, and neurological examination by a patient’s health care provider.
One of the most valuable aspects of an MRI is comparison of studies over time, to see how they change. To improve the accuracy of MRI comparison, it is best to get the studies completed at the same location. This makes it more likely that the techniques to capture and read the MRI are the same between studies. If you can’t get your MRI study completed at the same place you had it done last time, ask for a copy of the MRI (both the imaging files and the report) from the last place, both for your own records and to share with your providers.
While it is always better to review an MRI report with your health care provider, with a little bit of understanding of terminology it is possible to make some sense of your MRI report even before communicating with your doctor.