The Differences Between Low Field and High Field MRIs

by | Dec 28, 2020 | MRI

Reading Time: 3 minutes

Magnetic resonance imaging (MRI) systems rely on their magnets to produce strong magnetic fields that are potent enough to capture high-quality images of a patient. Thanks to this critical functionality, many hospitals purchase MRI systems so their doctors can make accurate diagnoses. However, there are many MRI systems of different strengths, so deciding on your facility’s suitable variant can be an overwhelming process. 

Learning the differences between low field MRIs and high field ones will help you determine the best type of MRI to suit your patients’ needs. It will also help you understand the purposes they serve, as different strengths are best for various situations. Here’s what you need to know:


The Different MRI Fields

For an MRI system to produce the highest resolution of an image possible, it must create a strong magnetic field. Measuring the MRI’s magnetic field uses the unit of Teslas, and the most common MRI systems found in hospitals today are in the 1.5T range. However, some ultra-modern medical facilities have 7T MRI systems, classified as the ultra-high field. The sharp clarity of the images they produce makes them suitable for research purposes. 

Low field MRIs usually have a magnetic strength of around 0.3T or below. They’re typically open MRI systems, which means that the patient won’t be covered entirely within the magnet. Many full-body low-field MRI systems are affordable, making them an ideal choice for hospitals with smaller budgets. There are also low field MRI systems that are excellent at scanning the extremities, which may be a machine to consider if your patients regularly experience issues in these areas.

Meanwhile, high field MRIs range from 1T to 3T and are available in open and closed systems; however, 3T systems are usually closed. Since the magnet completely encloses patients, the system can create more detailed images at a faster pace. High field MRIs are more commonly found in hospitals since they produce higher resolution images, allowing doctors to make more confident and accurate diagnoses on conditions.


The Different Purposes of Low Field and High Field MRIs

While low field MRI systems produce a weaker magnetic field, that doesn’t mean they don’t serve a specific purpose. Medical professionals use these systems to supply motion studies of joints possible only in open MRI systems. Additionally, extremity MRIs offer much more precision when detecting and analyzing bone erosions and bone marrow edema. 

On the other hand, using high field MRIs is possible for more complex processes, such as neuro and orthopedic imaging. They also generate more dependable scans of organs, making it easier for doctors to monitor treatment for diseases or conditions in the liver, kidney, or heart. 


Why Hospitals Prefer High Field MRI Systems

Given the strength of high field MRI systems, they offer hospitals more flexibility and use than low field systems. They can also scan a broader range of patients and conditions since they produce sharper, more precise images, thanks to its higher-powered magnetic field. High field MRI systems can diagnose complicated conditions like traumatic brain injuries, multiple sclerosis, dementia, artery diseases, pinched nerves, and many more. They also operate much faster than low field MRI systems. With its broad range of uses, it’s no wonder that hospitals tend to invest in high field MRIs.

Given all its benefits, high field MRIs also have their disadvantages. 3T MRIs, in particular, may make it more challenging to conduct scans on patients with claustrophobia or anxiety because it is an enclosed system. While high field MRIs work faster than low field ones, patients must lie still for about 30 minutes or longer. 

High field MRIs are also incredibly expensive both in purchase, installation, and maintenance. MRI parts like liquid helium, a nonrenewable source, are necessary to cool their superconducting magnets. Given the nature of liquid helium, it can be costly, adding to the long list of expenses associated with high field MRIs.



Both low field and high field MRI systems have their benefits and purposes. High field MRI systems are generally capable of much more than low field MRIs, but they also come with their disadvantages. It is ultimately up to your medical facility to determine your needs and find the system that best serves you and your patients.

DirectMed Parts is the leading supplier for medical imaging parts and services that offers a wide range of CT and MRI parts compatible with many systems, like the Siemens MRI Symphony. We also provide MRI coil repair, system upgrades, and relocation or installation. Contact us today to find the best MRI system for your facility!

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