When neurosurgeons at the Foothills Hospital of Calgary, Alberta, close a skull after brain surgery, they know exactly what they have accomplished. Two, three, even four times during a complex procedure, the OR team stands back as iMotion, a 1.5-tesla MRI scanner, rolls into the room on a suspended track, encircles the head of their patient, bangs out high-resolution images, then retreats behind closed doors.
“It’s a little bit like moving the mountain to Muhammad, but it is a question of safety,” said John Saunders, founder of IMRIS (Innovative Magnetic Resonance Imaging Systems), the company that developed iMotion.
Other surgical suites using intraoperative MRI move the patient rather than the scanner. IMRIS does the opposite because, in at least some instances, the patient should not be moved, neurosurgeons advised IMRIS.
So far, the only patients who can benefit from iMotion are those who go to Foothills Hospital. But Saunders and his colleagues would like to change that. Earlier this year, iMotion was cleared by the FDA. Saunders is now intent on selling the unit to sites in the U.S. and around the world.
BrainLab, a company best known for image guidance and radiosurgery systems, has agreed to be IMRIS’ sales and marketing arm. The Munich, Germany-based company, which has distribution channels in 70 countries, including the U.S., has also taken a 16% equity stake in the Canadian company.
A start-up based in Winnipeg, Manitoba, IMRIS was founded on the observation by Dr. Garnette R. Sutherland, a neurosurgeon at the University of Calgary, that MRI could improve the planning and monitoring of complex neurosurgery. Sutherland made the comment to Saunders, who was then a researcher at Canada’s National Research Council Institute for Biodiagnostics. The idea simmered as a pilot research project at NRC, then took hold after Saunders founded IMRIS.
As installed at Foothills Hospital and cleared by the FDA, iMotion is composed of some of today’s most advanced technology. The cornerstone of the system is a short-bore magnet measuring 1.4 meters and featuring a patient aperture of 72 cm. A self-shielded gradient coil operates at 25 mtesla per meter with a 300-microsecond rise time. A digital, high-powered radio-frequency system supports rapid, high-quality scans, including fat saturation and echo-planar imaging. Advanced shimming produces a highly homogeneous field. Active shielding decreases the fringe field, restricting the 5-gauss line to a radius of under three meters — tight enough that OR walls need not be modified.