Coil developer seeks to popularize technology for 3T and above

Design offers advantages for patients and users

The mightiest MR scanners cannot unlock their true potential because they lack the proper coil technology, according to executives at a small company in Minneapolis. The privately held company, MR Instruments, wants to provide its proprietary key--transverse electromagnetic coils.

TEM coils boost the MR signal and improve spatial coverage of high and very high field systems, according to proponents of the technology. These coils, which rely on distributed circuits rather than "lumped" element circuits, perform more efficiently at high frequencies and very high field strengths such as 3T and above. They can also be built to larger dimensions than conventional coils, say their developers, providing opportunities in body work as well as head studies.

"We have the fastest front end of any coils in the industry," said MR Instruments CEO Kevin Sundquist, a 25-year veteran of the medical device industry with experience in product rollouts in several modalities including MR, CT, and ultrasound. "The tunable/detunable electronics allow very fast switching."

The company has developed TEM head, body, and surface coils for 3T, 4T, 7T, and 9.4T. Although TEM excels at 3T and above, the technology is applicable to lower fields as well. The firm has developed, for example, a 1.5T head coil.

Working with six full-time staff and eight consultants, MR Instruments has a capacity of about 10 coils per month. The simplified design of these coils markedly reduces the number of components and, consequently, makes the coils more patient-friendly. Head coils typically are made up of more than 200 pieces, Sundquist said. MR Instruments' head coil has 15. The design is more open than conventional coils, particularly birdcage head coils, whose name accurately reflects their appearance. The TEM head coil, by comparison, features an open face that does not obstruct the patient's vision.

These coils are easy to use and flexible in design and application. They can be tuned, matched, and balanced in two to three minutes; can be designed for use in quadrature as well as linear fields and tuned to more than one frequency; and are inherently self-shielding.

TEM coils evolved from work done by J. Thomas Vaughan Jr., Ph.D., whose research in very high field MR goes back to the late 1980s. As the company's chief technology officer, Vaughan, who is currently an associate professor at the University of Minnesota in Minneapolis, continues to guide the engineering of the coils. Sundquist and his management team are in charge of business development.

"We have put a company behind Tommy's technology," said sales director Steve Zastrow, who served 13 years with Medrad, a major developer of MR coils and contrast injectors, before joining MR Instruments. "With TEM, and the manufacturing behind it, we can meet the needs of the customer."

For the time being, most of those customers are end users, Zastrow said, not OEMs who would market TEM coils with their own multimillion dollar scanners. Eventually MR Instruments hopes to land a supplier agreement with one of the major OEMs. In the meantime, however, Zastrow is pitching TEM coils to MR sites that--although they have access to coils offered by OEMs--can be convinced to buy from MR Instruments.

The majority of prospective customers are looking for improved resolution at 1.5T or very high field. This can be achieved with single-tune TEM coils, Zastrow said. A few, however, are experimenting with dual-tune coils optimized for sodium, phosphorus, or fluorine. Such a varied product offering requires flexibility in coil development and manufacturing process, a hallmark of TEM and a business requirement for a fledgling company hoping to make it in MR, according to Zastrow.

"We're going where the business is," he said.