IT ALL STARTED WITH THE BRAIN
The development of many imaging approaches now applied to different diseases and conditions was initially driven by a need in neurosurgery. The brain is enclosed in a bony box, making it difficult for the surgeon to visualize various structures, and yet more than in any other organ of the body, surgeons need to know precisely where and what they are cutting. "It is critical to preserve any healthy tissue," says Alexandra Golby, head of NCIGT's Image-Guided Neurosurgery core. "You cannot take a little bit extra because that could lead to lifelong deficits."
Thanks to advances in several types of imaging technologies over the past 100 years, neurosurgeons today have access to images of the main structures, or landmarks, in a patient's brain prior to an operation — like having a roadmap before going on a trip. Golby has been working to add "function" to the map.
“Not all areas of the brain are equally important,” she says. “For example, some areas are critical for motor and visual skills. But no labels in the brain read ‘Don’t cut here.’” To determine where these critical areas are, Golby uses functional MRI, a technique that detects blood flow changes in the brain, indicating brain activity. “Functional MRI is becoming slowly accepted as a clinical tool for presurgical mapping,” Golby says. “It is a technically demanding procedure. What we are trying to do now is to make it more turnkey.”
Another imaging technique that adds new landmarks to the preoperative map is diffusion tensor imaging, a variation of MRI that detects connections between different brain areas. "We are trying to combine as much information as possible," Golby says. "The goal is to get as complete a picture as possible." In addition to taking images before an operation, NCIGT researchers have pioneered the use of MRI to obtain pictures of the brain during an operation, or intraoperatively. "During surgery, the brain shifts due to many factors, including resection of tissue, making preoperatively acquired information progressively less useful," Golby explains. "So intraoperative imaging helps the surgeon know where the limits of resection should be."
But how can all these pre- and intraoperative imaging data fit onto the surgeon’s roadmap? This is where bioinformatics and computer programming play a part. In collaboration with researchers at the Center for Integration of Medicine and Innovative Technology, another NCRR-funded Biomedical Technology Research Resource, and the NCRR-funded Biomedical Informatics Research Network (BIRN), NCIGT scientists have developed computer programs and algorithms to analyze and integrate different imaging data. More information about BIRN
The software package 3D-Slicer (freely available to all researchers at www.slicer.org) is widely used to construct and visualize collections of MRI data. With Slicer, the surgeon can manipulate the data to obtain images of the brain from different angles and zoom in at different sites. In addition to producing 3-D models from conventional MRI images, Slicer presents information derived from functional MRI, diffusion tensor imaging, and electrocardiography. Researchers are now adapting Slicer to other applications. "Neuroimaging is very sophisticated, but many of the same techniques are now being adopted in other areas, such as prostate surgery," Tempany says.
LOOKING FORWARD
Many of the technologies used to image the body before and during surgery are becoming components of routine surgical care. Eventually, Jolesz and Tempany would like to see all these modalities present in the operating room and seamlessly interacting with each other. Next year, they will unveil the first prototype of their "operating room of the future," which will integrate several imaging devices, instruments, and tools into a single, multimodal image-guided surgical suite (see image).
Although plans for most operating rooms of the future combine one or two modalities, NCIGT's advanced multimodality image-guided operating suite will comprise a 3-Tesla MRI scanner, a positron emission tomography and computed tomography scanner, an X-ray machine, a surgical microscope, and a sophisticated surgical table that moves the patient between stations. It also will include detailed visual displays to guide a surgeon during medical procedures. "We are completely changing the operating room," Jolesz says. "Today, it is a non-tech environment, but in 10 years, there will not be any operating rooms without imaging systems."
The NCIGT is somewhat unique in receiving core funding from several NIH institutes, and its investigators also have individual research grants. This integrated support allows them to conduct cutting-edge research and development that would be difficult to do elsewhere. But another important component of the NCRR grant is dissemination. "Our methods are given to other people," explains Jolesz. "That is the difference the NCRR grant makes. It allows for the spread of technology. We also provide training. An important aspect of technology is education, which is critical if we want new approaches to be adopted."
And as the approaches developed by researchers at NCIGT and other biomedical technology research resources continue to make their way into the clinic, patient care will be dramatically transformed. The biggest change that will occur, according to Jolesz, will be minimizing the invasiveness of the surgery. With new imaging methods, tumors will be destroyed while other tissues are left intact, and surgeons will have tools to better navigate the brain and help patients with Parkinson's disease or epilepsy. The operating room of the future will result in safer procedures, fewer complications and side effects, and shorter hospitalizations. Some patients have already reaped the benefits.
For more information about these and other technologies that are supported at BTRRs, visit www.ncrr.nih.gov/btrr.