MRI Didn’t Know That!

An MRI is a type of scan that lets doctors see detailed pictures of the inside of
your body without surgery or radiation. It uses a strong magnet and radio waves to
create these images. Most MRI machines have either a 1.5Tesla or 3Tesla
magnet— “Tesla” is the unit used to measure how strong the magnet is (not the vehicle in this case). A higher Tesla number means a stronger magnet inside the machine. A 1.5T MRI is the standard scanner used in most hospitals. It gives good image quality, takes a reasonable amount of time, and is comfortable for most patients. For most medical needs, a 1.5T MRI provides all the detail doctors need to make a diagnosis. A 3 Tesla MRI gives much sharper and more detailed pictures than a standard 1.5 Tesla MRI. Because the magnet is twice as strong, the images come out clearer, with better contrast, and the scans can be done faster. According to The Journal of Magnetic Resonance Imaging, 3T MRIs are especially good at spotting very small problems in the brain that might not show up on lower strength machines. To put it in perspective, a 3T MRI magnet is about 60,000 times stronger than the Earth’s natural magnetic field (sounds a little intimidating if you ask me)! That extra strength helps doctors see tiny abnormalities more easily and make more confident diagnoses. When it comes to brain scans, 3T MRI really stands out. Because the magnet is stronger, it can do special types of imaging—like showing which parts of the brain are active, how blood is flowing, and how nerve pathways are connected. These kinds of scans help doctors plan surgeries, check for brain injuries, and track neurological conditions. There are a few practical differences you might notice during a 3T scan. The machine is louder than a regular MRI, and you might feel a little warmer. That’s because the stronger magnet puts a bit more energy into your body, which can create a small amount of heat. Thankfully, many people barely notice it, but it’s something to be aware of. MRI does not use radiation, which is one of its major advantages over CT scans and X-rays. However, the powerful magnetic field creates specific safety concerns, and these are amplified at 3T. The most important risk involves metal. The MRI’s strong magnet can pull in metal objects with a lot of force. If something made of the wrong kind of metal gets too close, the magnet can yank it toward the scanner so fast that it basically becomes a projectile. It is essential to make sure your dr is aware of ALL metal implants as some implants deemed safe at 1.5T are not necessarily safe at 3T. You should also be cautious of any clothing you’re wearing as some clothing has metal fibers woven into the fabric. Due to this fact, many times before an MRI, you should be given a hospital gown. If 3T is twice as strong as 1.5T, imagine the power of 7T machines, which are more than twice as strong. 7T MRI was approved for clinical use in the United States in 2017 and is slowly appearing in major academic medical centers (Recently, accredited for clinical use in a collaboration with University of Alabama at Birmingham and Auburn University). It offers even finer detail for certain
neurological conditions, detecting more white matter changes in the brain than 3T
MRIs. This advanced imaging technology can identify epileptic lesions that 3T MRI often misses, increasing the chances of the patient achieving seizure freedom.   However, 7T scanners remain rare, expensive, and limited in the types of exams they can perform. For now, 3T MRI is about as powerful as most people will ever need for regular medical scans. It offers a great mix of high quality images, flexibility for different types of exams, and availability in most hospitals and imaging centers. In a study comparing 3T to even more powerful 7T machines for detecting brain injuries in people with repeated head trauma, 3T reliably identified cerebral micro hemorrhages at rates comparable to the stronger scanner. In late 2017, Mayo Clinic in Minnesota became the first center in North America to use clinical 7T MRI and a second 7T scanner was installed at Mayo Clinic in Florida in 2021. Mayo Clinic is one of the few centers that routinely use 7T MRI to assess individuals with epilepsy. (As of now, there are fewer than 10 7T MRI machines accredited in the United States for clinical use.) The 7T MRI offers much higher resolution images, which may help doctors identify tiny brain abnormalities and lesions that are often missed with traditional imaging. Finding these lesions can be critical for diagnosis, treatment planning, and, in some cases, surgery. By enabling earlier and more precise medical decisions, this enhanced level of detail has the potential to greatly improve patient outcomes!