InnerVision looks into niche MRI with compact 0.14-tesla scanner

U.K. government helps firm reclaim lost turf

Inner Vision MRI of the U.K. is the latest company to enter thegrowing niche MRI market. The firm chose the San Francisco meetingof the Society of Magnetic Resonance in August to unveil its new0.14-tesla permanent magnet system, designed mainly for orthopedic,pediatric and interventional procedures.

The scanner has already been installed for research purposesat Middlesex Hospital in London and is likely to be sold commerciallyin Europe next year at a cost of about $300,000.

A market launch in the U.S. will take longer because no distributorhas yet been found and obtaining regulatory approval from theFood and Drug Administration is complex, according to the company'sdirector, Martyn Paley, a physicist who is also senior lecturerat Middlesex.

Although Paley anticipates that the majority of the machine'sinitial users will be radiologists, its use could eventually spreadto other medical specialists.

"We've had a good response from a mix of different institutions,both hospitals and universities," he said. "In mostcases, we think the system will act as a supplement and a reservefor the existing whole-body scanner, taking some of the overloadfrom the main machine and also fulfilling a training function."

The magnet has a patient aperture of 33 x 8 inches. Housedin a single enclosure, the system weighs less than 900 lbs andthe stray field extends 10 inches in front of the system. Gradientstrength of 15 mtesla/meter and rise-times of 400 microsecondsprovide access to a range of imaging sequences.

No cryogenic or water cooling is necessary for the magnet,and a single-phase electrical supply using less than 3 kW of poweris required.

Among the advantages claimed by Paley for the system are:

** Users can relocate the scanner easily around a hospital;

** Good access is provided for all procedures;

** The reduced stray field allows equipment such as life-supportmachines to be located near the magnet;

** The low operating frequency (6 +/- 0.1 MHz) means that radio-frequencyheating effects are minimal; and

** Ultrasound may be performed with the patient in situ.

The almost inaudible gradient system could also have importantadvantages in neonatal and pediatric applications compared toconventional high-field systems, Paley said.

Most of the funding for the project came from the U.K. Departmentof Trade and Industry, which provided $250,000. The lack of amajor domestic MRI manufacturer continues to cause the Britishgovernment great embarrassment, given U.K. scientists' leadingrole in the early development of MRI, Paley said.

"It's early days yet, but we'd like to think that we'rehelping to bring the technology back to the U.K.," said Paley,who has worked in MRI for the past 12 years, having previouslybeen at the University of Nottingham.