Fielding Questions
By Keith Loria
Radiology Today
Vol. 23 No. 7 P. 20

Manufacturers have a new slant on low- and mid-field MRI.

A majority of MR systems on the market utilize a 1.5T to 3T magnet, but these high-field MRs are getting significant competition from low-field (0.1T to 0.3T) and mid-field (0.3T to 1T) systems. Wes Gilson, senior director of MR business development for Siemens Healthineers, says there is a movement to explore the potential of what can be done beyond the 1.5T and 3T space that companies have been focused on for the past 20 to 30 years.

“We still continue to innovate [in the high-field space], as do other vendors, and we’re not abandoning that by any means,” Gilson says. “But we see an opportunity [in mid- and low-field technology] with the latest developments in both hardware and software, from new coil technologies to gradient technologies to deep learning construction, and what those types of technology have done to elevate our imaging equipment.”

Declines Over Time
According to evidence that GE Healthcare has collected from the market, the global MR market has increased significantly since COVID, and the volume of procedures has expanded significantly. “We estimate that the number of procedures in 2021 has exceeded 200 million, and probably half of them are in Asia,” says Ioannis Panagiotelis, chief marketing officer of MR for GE Healthcare. “This huge growth in procedures has driven the demand for more MRI systems to be purchased. That has led to double-digit growth.”

The low-field market—which Panagiotelis defines as being under 1.5T—has not seen the same sort of increase that high-field has, though he points out that the numbers aren’t declining. “Most of these are open systems, and the past decade has really only seen single-digit market share,” Panagiotelis says. “However, there are competitor systems that are not open—they are cylindrical—that have been introduced in the last few years. But those numbers don’t move the needle much in the low-field market.”

GE is not a player in low-field MR, currently, though it once was. Panagiotelis notes, however, that the company is exploring opportunities in super value segments such as low-field MR and is doing research but doesn’t have any plans for new systems in the near term.

Still, Panagiotelis says low-field MR has seen its main volume over the years decline because image quality and acquisition times have made low-field MR systems less attractive than conventional systems. “So, today, the main systems you see in this area are open systems, which compensate for the fact that they are compromising image quality and speed by offering more openness, addressing needs related to anxiety and claustrophobia,” he says. “The other thing that has happened through the years is the number of procedures has significantly increased by about 5% a year per device.”

This means that customers will want to offer their patients faster scanning, but Panagiotelis believes it shouldn’t be at the expense of image quality. “In the end, you want to diagnose, so you do need image quality, which is why we have seen some of the volume of low-field decline,” he says.

However, GE has seen potential new life in low-field quality, thanks to deep learning technology, which is why the company is doing more research. “If someone can offer a low-field system that is using a cheaper magnet but can compensate for the image quality by offering deep learning technology, this may be the solution that will be attractive for a big part of the market,” Panagiotelis says. “Even today, more than 6 billion people have no access to MRI, so offering a lower cost, good performing system would definitely help many. This is why the industry hopes low-field MR with deep learning will be that solution.”

There are advantages associated with mid-field and low-field MRI, from access, design, and cost perspectives, and, when combined with some of the latest technologies, they produce better solutions to address diagnostic needs in ways that weren’t available before.

Increased Access
Gilson says Siemens Healthineers has been active in the mid-field space. The company’s MAGNETOM Free.Max and new MAGNETOM Free.Star are lower priced, whole-body MR scanners designed to help improve patient access, boasting 80 cm and 60 cm patient bores, respectively, with each utilizing a 0.55T field strength with deep learning technologies and advanced image processing.

“The MAGNETOM Free.Max basically changed the direction of MRI systems going forward,” Gilson says. “There was a desire to have more access to patients and, by introducing a new system, that allows some of the spaces that were still being excluded because they were too large or claustrophobic. We now have the wider bore system to be more inclusive for those types of patients.” For both MR scanners, deep resolve algorithms perform targeted denoising and employ deep learning to deliver sharp, high-resolution images, elevating image quality to a level previously achievable only using MR scanners with much higher field strengths.

Siemens Healthineers’ MAGNETOM Free.Star costs approximately 30% less throughout the lifecycle than conventional MR scanners. At just 3.3 tons and less than 80 inches high, the lightweight whole-body MRI system requires under 1 L of liquid helium and no quench pipe, which reduces infrastructure and lifecycle costs due to lower energy requirements.

“By being able to redesign the system to a lower cost point, the savings can be passed along to the consumer,” Gilson says. “Cost has been a major factor. As we look at customers who are most interested in the system, one of the common themes is that it has a lower cost of ownership, allowing them to afford a new system vs having to buy a refurbished system.” By getting a new system, they can extend the lifespan of their systems, a critical concern for health care providers of all kinds.

“We have customers coming from traditional markets—hospitals and imaging centers—but we’ve also sold to orthopedic practices, pain management practices, and even a neurosurgery group,” Gilson says. “We’ve had a federally qualified health center, so customers are coming from all types of venues.”

New Opportunities
While these MR systems are being used in the same ways as traditional MR, the uniqueness of low-field and midfield MR allows for new clinical opportunities. Gilson points to imaging implants, which was challenging in the past, as one area people are exploring.

“Distortions can be reduced, so even with things like diffusion imaging, we’re seeing positive results come out of that,” he says. “And we’re starting to look at areas like lung imaging, which is traditionally not something that is easy on MRI, but there’s an opportunity there.”

From what Panagiotelis has seen, customers who may be interested in new low-field systems are those who have site challenges because low-field systems are lighter and easier to install than high-field systems. “Some buildings that have certain restrictions may be willing to compromise on image quality and speed because they are not in a position to install the high-field systems,” he says.

Low-field and mid-field MRI tech has been around for a while, but a new wave of equipment is quickly bringing the tech to the forefront of hospitals and diagnostic clinics. “We’re seeing success in this space now, and I think we can push the field forward,” Gilson says. “I don’t know what other vendors will do, but I imagine there will be growth in this mid-field segment going forward as we leverage it to access new markets and bring MR to places it hasn’t been before—particularly with advanced capabilities.”

Gilson anticipates that there will be continued growth and interest in these MR systems as new clinical opportunities arise. “We see this as an opportunity to take MRI to places that haven’t had access to it before or where it was extremely limited,” he says. “We’re also working on building the services to support the equipment, such as remote scanning. I see the potential for growth in the number of mid-field systems and providing access for those around the world.”

— Keith Loria is a freelance writer based in Oakton, Virginia. He is a frequent contributor to Radiology Today.

Recent Advances Move the MRI Field Forward
United Imaging is currently focused on the mainstream field strengths of 1.5T and 3T, which are the vast majority of what is used clinically today for MRI. However, lower field strengths may offer some advantages, says Abram Voorhees, PhD, vice president of MR and CT for United Healthcare. “Low-field magnets are of interest for a number of reasons, to potentially help lower the cost of the equipment and increase patient comfort with an open design or larger bore,” Voorhees says.

Patient comfort, claustrophobia, anxiety, and patient size/body habitus can all limit access to MRI for patients. “United Imaging has responded to these patient needs with a 75 cm ultrawide bore (called the uMR OMEGA), which provides more space to help accommodate more patients,” Voorhees says. “Even though a magnet of this size is more technically challenging to engineer at higher field strengths, we selected a field strength of 3T to provide adequate signal for imaging. Higher field strength can be used for faster exams and/or higher resolution. In addition, higher field strength provides more signal to ensure diagnostic image quality in patients of larger body habitus.”

David Spagnoli, head of product management MR in precision diagnosis at Philips, says the company introduced the first and only 1.5T 70 cm MR system enabling helium-free operations—the Ingenia Ambition equipped with the BlueSeal magnet. “BlueSeal magnet requires only 0.5% of helium, compared to a conventional Philips MR system,” Spagnoli says. “BlueSeal does not require vent pipes and is about 900 kg lighter than conventional equipment available in the market, making the installation of the system more flexible and potentially less costly.”

The MR 5300 incorporates the BlueSeal magnet for helium-free operations and AI-driven technologies designed to automate the most complex clinical and operational tasks. It’s also equipped with lightweight and flexible coils, which make it possible to quickly connect and prepare patients for imaging—helping to shorten set-up time for routine exams by up to 30%.

— KL