Earlier this year Stollery Children’s Hospital and the University of Alberta Hospital in Edmonton opened The Dan and Bunny Widney Intraoperative Magnetic Resonance Imaging (iMRI) Surgical Suite to give Albertans who need complicated neurosurgery access to a sophisticated surgical suite.
Surgery is the primary treatment option for patients with brain tumours. The goal of surgery is to remove the entire, or as much as, the tumour whenever possible as any remaining tumour cells may grow back. Studies show that the extent of tumour resection is directly correlated with improved outcomes in both children and adults with brain tumours. However, the complete removal of a brain tumour remains a challenge depending on its size, shape and location.
There are risks and possible complications every time brain surgery is performed. The ideal situation is performing the procedure once and to do it right. Installed by IMRIS, Inc. of Winnipeg, the VISIUS® Surgical Theatre with iMRI puts at our fingertips the tools needed to perform the most complicated neurosurgeries, as well as complex surgeries for patients with epilepsy, or head, neck and vascular issues.
This state-of-the-art IMRIS iMRI suite provides the team of neurosurgeons and radiologists unprecedented precision and finely detailed images of the surgical progress in real-time during a procedure. Surgeons use this imagery, along with powerful new microscopes specifically designed for neurosurgery, to confirm they have completely removed as much brain tumour tissue as possible, potentially preventing the need for follow-up surgeries.
The VISIUS iMRI suite includes a six-tonne, 3-Tesla MRI, that moves between two rooms – one for surgeries and one for diagnostic use – on rails mounted on the ceiling which eliminates having to transport or reposition the patient for imaging.
Unlike other iMRI systems which require moving the patient from the surgical position and into the scanner, the IMRIS surgical suite limits risks associated with patient movement such as brain shift and monitoring equipment issues.
Because the naked eye is insufficient for confirming that the entire tumour has been removed during surgery, a follow-up MRI is required to confirm the extent of resection. Before the iMRI, patients may waited months to have a scan to see if the entire tumour was removed. For pediatric patients, identification of residual tumor may mean the need and risk for a second surgery.
With the new technology, on-site radiologists who can take multiple images during the surgery can immediately give surgeons exact directions to where any remaining tumour is located. In a way we can call this a GPS for the brain because of it’s ability to find and localize residual tumour material.
Neurosciences hospitals around the world with multi-year experience with iMRI have reported significant reductions in re-operation rates. During the last 20 years, iMRI has been used to assist neurosurgeons in surgical planning and decision making on how to approach assessing tumour removal.
In the last few years, the imaging quality has improved by bringing high-resolution (high-field) scanners into the operating space. The higher-field MR provides a high contrast equivalent to diagnostic imaging, allowing the detection of residual tumours and viewing eloquent structures. These intraoperative images provide neurosurgeons the ability to evaluate anatomical and pathological structures and overcome inaccuracies due to brain shift and updating neuronavigational data.
Implementing the new iMRI involved new workflow training and safety checks. Surgery can be performed as usual with standard instruments. Acquisition of the images takes place in a control room adjacent to the OR and takes 15-30 minutes, depending on the MR sequences (series of images with adjustments within software applications). Analysis of this data is performed by an experienced neuroradiologist who discusses the case and possible continuation or other next steps with the neurosurgeons. When not needed during the procedure, the magnet moves out of the way and back into a parking bay so the surgery can either continue or be completed using normal workflow.
The main indications for the using iMRI are the resection of gliomas and other types of tumours, but eventually will expand to help other patients for complicated tumours or disorders of the tongue, mouth, pituitary and other skull-based applications.