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Intraoperative MRI Technology Advances Brain Tumor Treatment

At the Podium – November 2007

By Ralph Dacey Jr., MD, and Michael Chicoine, MD

Over the past 20 years, magnetic resonance imaging has become an invaluable tool in many areas of medicine, from identifying tumors throughout the body to determining bone and tissue injuries and damage caused by heart attacks. For those of us specializing in neurosurgery, MRI allows us to perform noninvasive assessments of a tumor’s location with respect to functional brain areas and to differentiate between what is tumor and what is not – something not always possible when viewing tissue through an operating microscope.

In the past, the difficulty in distinguishing between diseased and healthy brain tissue was addressed with a follow-up MRI scheduled a day or so following surgery. In cases where residual tumor remained, a decision had to made about whether another operation was a viable option. Although an effective and important practice, the timing of the follow-up MRI was not ideally suited to the needs of the surgeon and patient.

That delay between surgery and follow-up MRI soon will be eliminated at the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine. In early 2008, we will become one of only a few institutions in the world to utilize high field strength intraoperative MRI – literally bringing imaging to the patient in the surgical suite. Surgeons will be able to operate on a brain tumor, slide the intraoperative MRI into the surgical suite for a scan and immediately assess whether more surgery is needed.

This capability is being made possible with the installation of an IMRIS MRI system that features a 1.5 tesla magnet. Mounted from a patented rail system in the ceiling, the device is housed in a “garage” between two specially designed operating suites in Barnes-Jewish Hospital. A state-of-the-art control room provides monitoring capabilities not only for MRI but also for other technologies, such as infrared camera-based surgical navigation devices, high-definition video and teleconferencing.

Considering the complexity of MRI, which uses a powerful magnetic field and radio waves to create cross-sectional images of the body, bringing this technology into a surgical environment requires careful thought and planning. The adjoining operating rooms are completely lined with copper shielding, and detailed safety procedures are being set up to ensure all metal objects are removed from the vicinity of the MRI unit when it is in use. These additional precautions are well worth the effort in light of the advantages intraoperative MRI will provide to patients. This equipment will allow us to improve the precision of brain tumor excision in adult and pediatric patients and reduce the need for – and risks of – additional operations. Eventually, the technology will benefit patients with tumors in the liver, pancreas, prostate and breast.

Intraoperative MRI also provides us with greater opportunities to advance our knowledge of how the brain works and, therefore, the effects of disease on the brain. For instance, researchers at Siteman, Washington University and Barnes-Jewish Hospital are striving to learn more about the way nerve fibers connect different areas of the cortex. This will help us understand how people recover from brain injuries like stroke and problems that might arise from tumors.

The IMRIS system is just the latest advance in a neurosurgery program dedicated to innovation. In 1999, our neurosurgeons performed the first human magnetic surgery, a safer way of manipulating surgical tools within the brain. The technology allows surgeons to use computer-controlled superconducting magnets to direct instruments on a curved pathway around sensitive structures, such as those controlling speech or vision. Also available is the Gamma Knife, a precise radiation therapy tool used to treat tumors and other brain abnormalities without an incision and with minimal effect on surrounding healthy tissue. In early 2008, this tool will be enhanced when an upgraded Gamma Knife Perfexion system becomes operational.

At Siteman, these advanced technologies are coupled with a coordinated, multidisciplinary approach to treatment that brings together the specialized expertise of physicians representing the fields of neurosurgery, neurology, medical oncology, radiation oncology, neuropathology, neuroradiology, nuclear medicine, otolaryngology, ophthalmology and plastic surgery. The addition of intraoperative MRI will allow this team to continue to provide the most advanced care available anywhere to patients with brain tumors and other brain disorders.

Ralph Dacey

Ralph Dacey Jr., MD, is Edith R. and Henry G. Schwartz Professor and chairman of neurosurgery at Washington University School of Medicine.

You can hear Dr. Dacey as a guest on Cancer Connection, Siteman Cancer Center's podcast series.

Michael Chicoine Michael Chicoine, MD, is associate professor of neurosurgery at Washington University School of Medicine.