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CMAJ Today!

Winnipeg becoming Canada's MRI capital?

Date: Aug. 9, 1999
Time: 3:24 pm

A custom-built magnetic resonance imaging scanner currently being installed at St. Boniface General Hospital Research Centre in Winnipeg means the centre will soon be one of the country's leaders in MRI capacity. The new, head-only MRI was built by the National Research Council's Institute for Biodiagnostics in Winnipeg. The $3-million machine will be used at the research centre's new Centre on Aging. Its powerful magnet, at 3 Tesla (T) compared with the more standard 1.5 T, allows researchers and clinicians to obtain considerably more information about a patient.

"We can look at blood flow during brain activity and we can see when increased blood flow occurs during [specific] activities and in what portion of the brain," explained Dr. Blake McClarty, professor and chair of the Department of Radiology at the University of Manitoba.

McClarty sees a number of potential applications for this functional type of MRI, including the the study of brain activity in poststroke patients or in patients with dementia. This kind of information, which identifies where brain activity occurs, has not been well documented. "This MRI looks at how the brain functions rather than looking at the anatomy," said Dr. Ian Smith, director general at the Institute for Biodiagnostics. "If a recovered stroke patient is paralysed on the right side, so activities on the left side of the body aren't happening, we can see how after about a year in [some] patients, the brain starts using its right side for these activities. We can see how the brain promotes recovery."

This understanding is significant because it could lead to the development of an artificial process to "recruit" brain activity.

The head-only, functional MRI at St. Boniface is the first of its type built in Canada. A second functional MRI has been constructed for use with vulnerable neonates in London, Ont. Winnipeg's head-only MRI will be used by a team of researchers and physicians at St. Boniface, working with NRC staff members.

Two other MRI machines complete the Research Centre's complement. One is for conventional diagnostics and the third is a C-shaped, 0.2 T MRI scanner manufactured by Siemens for an integrated system for robotic-guided neurosurgery. Developed by Mark Torchia, a research scientist at the centre, that system integrates MRI, laser technology and robotics.

"The concept was developed 8 or 9 years ago but the technology wasn't sufficiently developed," Torchia said. "With open magnets (C-shaped), this really allows almost complete access to the patient during scanning."

The integrated system lets a surgeon "image" the patient, view the tumour, determine the best trajectory for accessing it and then program the computer to guide the device to the tumour. "With this system we also can monitor the temperature of the patient throughout in real time so we don't kill [additional] tissue by continually firing the laser," Torchia added.

With 3 MRI machines, the St. Boniface research centre is poised to advance its diverse research projects and move them closer to clinical applications and possible commercial opportunities.

-- Jane Stewart, Winnipeg

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