Ultra Low Field MRI
There are many advantages to high magnetic field MRI, but there are also disadvantages. For one, developing this field strength requires huge magnets that need a large amount of liquid helium to cool to superconducting temperatures. The systems are expensive and difficult to build, and must be refilled with liquid helium repeatedly. This can present a large expense over time.
Another problem is that many people with implants cannot receive an MRI. (Click here for extensive list of implants)
List of implants that are contraindicated for MRI (from link): These include a huge variety of metal or conductive implants, such as cardiac pacemakers, aneurysm clips, implantable cardiac defibrillators, deep brain stimulators and other neurostimulators, other types of internal electrodes or wires, cochlear implants, hearing aids that can't be removed, implanted drug pumps (used for insulin, baclofen, chemotherapy, pain meds, and others), spinal fixation devices used in spinal fusion procedures, artificial heart valves, artificial eyes, eyelid springs, and other types of ear implants, medication patches that cannot be removed (used for nitroglycerine, nicotine, hormones and others), artificial limbs and joints, tissue expanders, IUDs, partial plate, braces or permanent retainers and some types of false teeth, body piercings or jewelry that can't be removed, some hair implants, some tattoos and tattooed eyeliner, radiation seeds for cancer treatments, as well as a huge number of surgical coils, filters, stents, shunts, mesh clips, staples, pins, rods screws, nails, plates and wires. This can also include metal flakes that penetrate the eye or other parts of the body in the course of metalwork.
In addition, MRIs are not recommended for women who are either pregnant or who may be pregnant, although it is sometimes used for diagnosis of health issues in pregnant women.
Roughly 6% of all people are claustrophic and cannot tolerate the MRI scan, requiring either medication or the scan to be stopped before it's completed.
Most magnetic resonance imaging (MRI) systems operate using very high magnetic fields. Clinical systems generally operate at 1.5 to 4 Tesla. The Earth's magnetic field averages 0.5 Gauss, or 0.00005 Tesla, making the field strength of clinical MRI systems over 10,000 times that of the Earth's. This higher field strength makes the systems operate at higher frequencies, leading to a higher energy signal being obtained from the patient and better signal contrast relative to noise. This improves image quality and allows the observation of smaller objects with greater contrast.
MRIs themselves are massive, weighing nearly 2000kg (4400 lbs). While some have been made small enough to be placed on a mobile truck, most require a specially built room.
This combination of factors results in MRIs being unobtainable by many people in developed countries due to their having a condition contraindicated for MRI, or who live in poor and underdeveloped countries that cannot afford or maintain a typical MRI system.
Developing an ultra low magnetic field MRI (ULF MRI). The ULF MRI operates at a magnetic field strength close to the of the Earth's, many 1000's of times lower than a typical MRI system. While images currently are not as good as large-field MRI systems, with further development, this system will likely improve and become useful for diagnostic imaging.
These systems would provide many benefits. They could be used by many more people than can currently receive and MRI. They would likely be cheaper to build and to operate, need much less cryogens than a typical MRI. They would be smaller and lighter, making them more portable. They would likely be much less expensive, allowing smaller and more remote medical teams to have access to an MRI. Poor and undeveloped countries that cannot currently afford an MRI might be able to afford this.
CONNECT TO ULFMRI ABSTRACTS AND WEBSITE FOR MICHELLE ESPY
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The abstracts of our published Ultra Low Field MRI studies can be found by clicking here.
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