Open or Superconducting – which type of MRI do you need?

There are several factors to consider while choosing an MRI – performance, scan time, spatial homogeneity, signal-to-noise ratio, the purpose of the MRI, and so on.

Both open and superconducting (closed) MRIs come with their advantages and challenges, but it’s up to you as a decision-maker at your healthcare facility to zero in on which one suits your requirements.

Here’s a breakdown of the two…

Advantages of Superconducting MRI systems

The advantages of superconducting MRI scanners are many. They have the highest temporal and spatial homogeneity or uniformity of magnetic field. With the magnetic field strength remaining consistent over time, image resolution is not going to reduce.

These MRIs also have a high signal-to-noise ratio, again meaning you will get a clearer image.

With superconducting MRIs, scan times are shorter, and the machines work with greater precision. These superconducting magnets, which use cooled liquid cryogens create strong magnetic fields of 1.5T to 3.0T or even higher, can produce detailed images of vascular and neuro structures. Some go up to 7T and Germany, China, and South Korea are considering building 14-T human scanners. A scanner of 3T can look at details of the brain as small as 1 millimetre. So, that’s the level of precision you are looking at. Finally, these MRIs use much less energy because they make use of a superconducting coil instead of a resistive one.

But, Superconducting MRIs have some limitations

• They are expensive to maintain
• Patients can feel claustrophobic as they are required to be inside the machine
• Patients who are obese or exceed the weight limit may not be able to use it
• People can experience dizziness when they move in and out of the scanner, some say they get a metallic taste in the mouth
• Requires strict protocol because of the strength of the magnetic field

Advantages of Open MRIs

A closed MRI has a capsule-like design, so the magnet surrounds the patient (hence the feeling of claustrophobia, which is common here). In an open MRI, the magnets are on the top and bottom, which allows for an opening on the sides. That’s why open MRIs can accommodate all types of patients in various positions including standing, sitting, and everything in between.

Open MRIs are more child-friendly too. Because the safety protocol is not as high as with a superconducting unit, parents can accompany their child inside the scan room during the exam. Also, another reason they are popular is open MRI units also come in smaller sizes for hands, feet, knees, etc.

Open MRIs have their limitations too

The field strength of an open MRI is half that of a superconducting MRI, which means the images are not as detailed. Also, they take longer to acquire. Now, because they are less precise, they cannot be used for studies of, say, nerves, that require greater accuracy of detail.

There are several factors that matter, and in the end, it all comes down to your specific requirements. Call our experts at Blue Star E&E for guidance on the right solution for your facility’s needs.