Rampable Intraoperative Magnetic Resonance Imaging

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MRI scanners generate exquisitely detailed images of brain and spinal cord anatomy and pathology. Although an engineering challenge, the placement of MRI systems in the operating room will revolutionize neurosurgical care. The first commercial iMRI systems were developed by GE based on a 0.5 Tesla magnet with Brigham and Women's hospital in Boston. In 1988 a group in Winnipeg (IMRIS) developed an iMRI system based on a 1.5 Tesla magnet which overcame many of the difficult issues discovered with the GE system. The iMRI technology enabled neurosurgeons to improve surgeries and outcomes. Intraoperative MRI has also identified a significant number of patients who harboured unsuspected, residual tumour at the end of surgery, thus sparing them the discomfort and expense of reoperation. The major problem with the IMRIS intraoperative system which is the market leader it was is too expensive. An even more serious problem was that the cost of renovation to the hospital was much more expensive and required operating suites to be closed for months during this renovation. Our new concept is to base the iMRI on a cryogen free magnet which can be ramped to 1 tesla and is stable at this field in 10 minutes. The magnet will be made with Magnesium Diboride (MgB2) which is a high temperature superconducting material. The magnet will be continually connected to a power supply and so will not require to be persistent allowing for the rapid ramp rate. The objective of the new design is to have an intra-operative MRI that take 2 weeks to install in a standard hospital surgical suite which can provide images of the same quality as a 1.5 Tesla commercial MRI on 2012 in the same time. The important research factor being developed in this proposal is to obtain image quality equivalent or better to what was obtained with the 1.5 tesla IMRIS systems. It is well known that the signal to noise ratio (SNR) increases linearly with field strength so a 1 Tesla magnet will have about 60% of the SNR to that of 1.5 Tesla magnet. We will develop RF coils and AI techniques to improve image quality.