HOW DOES MRI HELP DIAGNOSE MS?

Multiple sclerosis (MS) is considered an autoimmune disease of the central nervous system (brain, spinal cord, and optic nerves). It attacks the protective covering of the nerves, called myelin, causing inflammation and damage.

Myelin is necessary for the transmission of nerve impulses through nerve fibres and any damage can disrupt these impulses. Minor damage causes nerve impulses to travel with minor interruptions, but major damage can completely disrupt these impulses. If scar tissue replaces the myelin, the nerve fibres themselves can be damaged.

According to the Multiple Sclerosis Society of Canada, an estimated 77,000 Canadians are living with multiple sclerosis (MS). While it is most often diagnosed in young adults aged 20-49, it can affect all ages.

WHAT ARE THE SYMPTOMS OF MS?

MS is unpredictable and often develops slowly, with symptoms not appearing right away. It may cause extreme fatigue, lack of coordination, weakness, tingling, impaired sensation, vision problems, bladder problems, cognitive impairment, and mood changes.

When symptoms start and MS is suspected, your doctor will likely refer you to a neurologist, who will conduct a full medical history and a neurological examination to assess things like eye movement, strength, and coordination. To help establish a diagnosis of MS or monitor the course of the disease, magnetic resonance imaging (MRI) may be ordered.

WHAT DOES AN MRI LOOK FOR?

An MRI scan creates images by exposing hydrogen atoms in water molecules within our body to a magnetic field which controls the direction and frequency at which hydrogen protons spin. A radio frequency pulse is then directed at a specific area of the body, while smaller magnets are used to alter the magnetic field on a small, but localized level. As tissues responds differently to these magnetic field alterations, a computer can convert the data into a picture.

Because the layer of myelin that protects nerve cell fibres is fatty, it repels water. In the areas where the myelin has been damaged by MS, the fat is stripped away. With the fat gone, the area holds more water, and shows up on the MRI scan.

MRI is useful for assessing most body areas and is particularly useful in detecting central nervous system demyelination. It is a sensitive, non-invasive way of imaging the brain, spinal cord, or other areas of the body. Importantly, these images are obtained without a radiation dose to the patient.

An MRI’s magnetic field strength is measured in teslas (T). Mayfair operates both 1.5T and 3T MRI services at Mayfair Place, providing greater options to specifically meet the imaging needs of patients. The highly sensitive images from the 3T machine allows enhanced imaging of many areas of the body, including neurological imaging.

Sometimes a contrast agent is injected during an MRI scan to help detect areas of inflammation. In addition, repeat scans may be ordered to track the progress of the disease and help make treatment decisions.

ARE THESE EXAMS SAFE?

MRI images are created using a magnetic field, which can attract metal objects or may cause metal in your body to move. This means that before an MRI can be performed all patients will need to be screened to exclude internal metal objects that are not safe in the MRI. The inside of the MRI scanner can feel small to some people and there are noises caused by changes in the magnetic field, which require ear protection.

In Alberta, MRI exams are available in hospitals and covered under the Alberta Health Care Insurance Plan, but Mayfair Diagnostics also offers the same studies as private pay exams. In Saskatchewan, we offer MRIs as publicly funded, community-based services under contract with the Saskatchewan Health Authority and as private pay exams. Private MRI services in Saskatchewan are provided in accordance with and under the legislation of the Province of Saskatchewan.

Whether public or private, an MRI must be requested by a health care practitioner who will provide a requisition. Mayfair Diagnostics will schedule your exam and provide you with detailed information to prepare for it. Once your exam is completed, your images will be reviewed by a specialized radiologist who will compile a report that is sent to your doctor. Mayfair Diagnostics is owned and operated by over 50 radiologists who are sub-specialty trained, which guarantees an expert opinion of your imaging.

Mayfair Diagnostics offers MRI imaging as a private pay service at our Mayfair Place location in Calgary, and as both public and private pay exams at our Saskatoon and Regina locations in Saskatchewan. For more information, please visit our services page or call our toll-free number 1-866-611-2665.

REFERENCES

Healthwise Staff (2021) “Multiple Sclerosis: MRI Results.” www.myhealth.alberta.ca. Accessed August 7, 2022.

Multiple Sclerosis Society of Canada (2022) “About MS.” www.mssociety.ca. Accessed August 7, 2022.

National Multiple Sclerosis Society (2022) “Magnetic Resonance Imaging (MRI).” www.nationalmssociety.org. Accessed August 7, 2022.

Saskatchewan Health Authority (2020) “Multiple Sclerosis Pathway – Patient Information.” www.saskhealthauthority.ca. Accessed August 7, 2022.