Lightening the load

Dr. Mark Alexiuk, Wayne Schellekens, Senior Englineers, IMRIS; former University of Manitoba graduate student and IMRIS employee Szymon Rzeszowski; James Dietrich, RF Engineer, CMC Microsystems; and Dr. Greg Bridges, University of Manitoba

Workflow and patient care are both improved when optical fiber replaces copper cable in magnetic resonance imaging (MRI) systems used for real-time scanning during surgery. This improvement can give a company a distinctive competitive advantage and motivated a joint investigation by University of Manitoba researchers and the Winnipeg-based company IMRIS.

Magnetic resonance imaging is a technique that provides an unrivaled perspective on the inner workings of the human body by allowing detailed visualization of internal structures. The scanning process involves the use of considerable electromagnetic energy to align the magnetization of atomic nuclei in a patient’s soft tissues. A clinical MRI scanner has an extremely powerful high-field magnet with superconducting wires cooled by liquid helium to eliminate electrical resistance. A local receive coil is placed on the patient’s body and generates signals that describe the properties and location of the nearby living tissue. These signals are sent over cables to a computer which constructs an image.

This technology can be employed during the course of surgery on a patient. The MRI used in an intraoperative setting typically requires longer cabling between the local receive coils and the scanner computer than would be found in a standard diagnostic system. This arrangement allows the clinical staff to position the coil near the region of interest on the patient’s body and then move the scanner into place. The longer cables have been constructed to help mitigate the risks of heating induced by the radio-frequency current, but this construction also increases their diameter and weight, making them bulky and difficult to work with in real-world medical settings.

Winnipeg-based IMRIS is eager to improve the clinical workflow associated with such intraoperative imaging. This global company designs sophisticated MRI suites where surgeons can take advantage of current MR images throughout the surgical procedure. Members of the University of Manitoba’s Advanced RF Systems Laboratory (ARFSL) subsequently joined an IMRIS project to assess alternatives for intraoperative applications.

Fiber optic technology is a practical solution to address the project requirement, which was to devise an alternative to the large copper-wire based cables and reduce heat and weight. An important aspect of the project was to maintain the signal-to-noise ratio and very large dynamic range required in MRI. The effort also involved selecting suitable MRI-compatible, non-magnetic components. Dr. Greg Bridges, Professor of Electrical and Computer Engineering and his colleagues built a custom detector based on laser diodes intended for use in digital networks which they were able to configure to function in the MRI. Their research demonstrated the feasibility of multi-channel fiber optic links for cabling and produced positive test results that warrant a further stage of investigation.

“The project succeeded in setting an initial benchmark of technology capability,” says Dr. Mark Alexiuk, a senior technology engineer at IMRIS. “It gave us a good idea of what was possible with off-the-shelf components. Further work is required to optimize the channel.” Dr Bridges agrees, adding that “For IMRIS it was an important trial project. They gained valuable experience and information on the feasibility of the fiber optic technology.”

The collaboration has provided other gains for IMRIS including exposure to the next generation of graduates entering the work force. The company’s R&D effort is continuing and will be assisted by a recently recruited graduate from Dr. Bridges’ research group who participated in the initial project.

Dr. Bridges highlights the role of NSERC’s Engage program in enabling this collaboration between industry and academia. The initiative funds university researchers who are helping a firm to bring new technology into a commercial setting. The objective is not necessarily a final product that will be brought to market, but a valuable test of ideas or equipment that could prove essential to product development.

Bridges, who is principal investigator of the ARFSL, adds that the University of Manitoba’s laboratory was the ideal partner for IMRIS. The lab was created in 2004 as part of the National Microelectronics and Photonics Testing Collaboratory, an initiative of CMC Microsystems with the support of the Canada Foundation for Innovation. It is outfitted with state-of-the-art RF testing and analysis infrastructure that is available to researchers from across the country. Staff in Winnipeg initially set up the equipment for each test procedure and researchers can continue on-line from wherever they are located. The lab has offered this kind of remote service to over 100 clients.

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