Magnetic resonance imaging (MRI) has transformed medical imaging. This non-invasive test produces high-quality images of the body's internal structures without using harmful ionising radiation1. Today, MRIs are the preferred method for diagnostic imaging of soft tissue structures like the brain, spinal cord, musculoskeletal system, small bones, liver, and pelvic area2. They can also detect abnormalities in vascular structures such as blood vessels3.
As a patient, you may not realise that you have choices when it comes to the type of MRI technology that is used. Here, we’ll briefly review magnet strength, the differences between a 3T MRI scanner and a 1.5T MRI scanner, and how to decide which type of MRI technology to choose.
Understanding MRIs
How do MRIs work?
MRI scans produce detailed images of the body’s internal structures, such as organs and tissue. They produce these images by using the magnetic properties of hydrogen atoms, which are found throughout your body due to their abundance in water and fat4. When your body is in an MRI scanner, strong magnetic fields cause the hydrogen atoms to act as tiny magnets, and they all align with the magnetic field. Radio waves are used in short bursts to knock the hydrogen atoms out of their magnet-induced alignments. When the radio waves are turned off, the hydrogen atoms realign with the magnetic field, releasing a signal. This signal is detected by the scanner and used to create the image of the body4.
What Does the Term “Tesla” Mean in MRIs?
The T in 3T stands for Tesla, named after the inventor Nikola Tesla. In the context of MRIs, a Tesla measures magnetic field strength. For clinical use, MRI machines typically range from less than 1T to 3T5. For reference, a fridge magnet is about 0.001 T. In medical research, you can find ultra-high field (UHF) MRI scanners with 7T magnets or stronger6.
3T vs 1.5T MRIs
3T MRIs use a magnetic field twice as strong as 1.5T MRIs. This can provide both advantages and disadvantages.
3T vs 1.5T MRI Quality
An increase in magnetic field strength increases the signal received from the body. This increases the signal-to-noise ratio, providing an image with higher quality7. This may allow health professionals to more effectively assess the presence of abnormalities in the image and improve diagnostic confidence8.
However, increasing the magnetic field strength can also increase the signal from artefacts. Artefacts in MRIs are features of the final image that are not actually present within the body. They can be caused by movements of the person in the scanner, metal in the scanner, or an issue with the scanner9. Increasing the signal of artefacts can affect image quality and potentially result in misdiagnosis.
3T vs 1.5T MRI Speed
A 3T MRI machine can create high-resolution images faster than a 1.5T system7. Faster imaging means less time inside the scanner, making the scan more comfortable. In addition, a shorter scan reduces artefacts from motion – the longer the scan time, the harder it is for someone to hold completely still.
3T vs 1.5T MRI Noise
Although undergoing any MRI scan will subject you to loud noises produced by the machinery, 3T MRI scans are louder than 1.5T scans10,11. However, you will always wear ear protection during an MRI scan, and so the difference in noise should not cause any problems. At many of our Ezra locations, we also provide music in the scanner to make your experience more comfortable.
MRI Scan Safety: Implants and Tissue Heating
Approximately 20 percent of people undergoing an MRI have a form of medical implant, such as stents, pacemakers, or metal joint replacements12. There is the potential for these to be affected by the magnetic fields in an MRI scanner, causing damage to the device or even danger to the individual undergoing the scan. The majority of modern medical implants are MRI-compatible and so safe for use in an MRI scanner13. However, certain implants may only be safe up to 1.5T, making 3T scans unsafe11.
MRI scans can present further problems for those with medical implants due to processes within the scanner causing the metal to heat up. This problem may also occur if any metal is present in clothing, tattoos, or permanent makeup, and can cause serious burns. Due to the 3T MRI scanner being more powerful, it can cause increased heating11.
All Ezra members are required to fill out a medical questionnaire during the sign-up process. The medical staff at Ezra reviews this questionnaire to ensure the member is safe to proceed with a 3T MRI scan. On the day of the scan, members are also screened by an MRI technologist onsite to verify their safety. Members are also carefully monitored when within the scanner to ensure their safety.
What Scanners Does Ezra Use?
Ezra uses 3T scanners at the majority of their locations due to the improved image quality that can be obtained. In addition, 3T scanners are quicker at producing images of comparable quality, meaning that our members have to spend less time in the scanner. However, Ezra also offers 1.5T scanners at some locations, meaning that members with medical implants, or even those who are concerned or nervous about a stronger magnetic field, can still get one of our full-body MRI scans to screen for cancer or other abnormalities.
What’s an Ezra Scan Experience Like?
Ezra scans are quick, taking only 60 minutes to complete. During that time, Ezra screens up to 13 organs for visible tumours and pre-cancer warning signs. You don’t need insurance, and a referral will be provided by a licensed clinician when you’re approved for the scan.
Here’s a breakdown of what to expect during your Ezra screening:
- Be sure to complete your medical questionnaire by the date requested and arrive at your appointment at least 30 minutes early. When it’s time for your scan, a facility member will escort you to a dressing area where you can change into Ezra-provided PJs and slippers.
- Before your MRI scan, ask the technologist any questions you have and listen carefully to all instructions. During your scan, you may be able to listen to music with special headphones. But be aware that your MRI technologist may also give you instructions during the scan.
- The Ezra Full Body Scan usually takes less than 60 minutes. Once your results are ready, a clinician will follow up within 5-7 days. You may also opt for a telehealth appointment to review the findings and answer questions.
It's important to note that although the Ezra Full Body Plus scans may offer insights into the following areas, this list may not encompass all potential findings.
- Brain: The scan can detect potential brain masses, abnormal fluid collections, and signs of possible brain ageing.
- Spine: It can identify potential herniated discs, spinal cord compression, or vertebral fractures.
- Lung: The low-dose CT scan offered in the Full Body Plus is sensitive enough to spot possible nodules as small as 1mm.
- Gallbladder: The scan can highlight potential gallstones and gallbladder polyps.
- Spleen: It can identify possible enlarged spleens and splenule (accessory spleen).
- Adrenal Glands: The scan can detect potential adrenal nodules.
- Ovaries: It can find potential ovarian cysts, polycystic ovaries, and endometriosis.
- Thyroid: The scan is sensitive to potential thyroid nodules, thyroiditis (thyroid inflammation), and goitres.
- Liver: It can spot potential liver masses, fatty liver disease, and iron overload.
- Pancreas: The scan is equipped to detect possible early pancreatic tumours (known as intraductal papillary mucinous neoplasms or IPMNs) and fatty pancreas.
- Kidneys: It can spot potential kidney masses, hydronephrosis (urine blockage), nodules, and kidney stones.
- Bladder: The scan can identify possible thickened bladders (trabeculation).
- Uterus: It is designed to find potential fibroids.
- Prostate: This scan may help detect potential prostate cancer and prostatitis (prostate inflammation) in men.
Be Proactive: Book an Ezra Full Body MRI Scan Today
In medical imaging, the choice between a 3T vs 1.5T MRI can make a difference to your healthcare experience. While both help to detect multiple conditions, one may be better suited to your specific health circumstances, such as whether you have any medical implants or tattoos. Talk to the medical staff at Ezra if you have any concerns about which scan to undergo.
You can easily book an appointment online for Ezra’s Full Body or Full Body Plus scan service in less than five minutes. Pricing is transparent, and you can even use your health savings account (HSA), flexible savings account (FSA), or finance through Affirm for easy monthly payments.
