Monitoring the Brain in 3-D
New technology gives surgeons a 3-D image of the brain.
June 28, 2007 — -- Duke University researchers have developed an ultrasound endoscope that will give surgeons a 3-D view of the brain during and after an operation. If it proves safe and effective in animal and human tests, the 3-D probe could provide a cheaper, more effective alternative to the two-dimensional scans currently in use. The probe has been used to image dogs' brains and will need to undergo clinical trials before it can be used in the operating room.
Currently, neurosurgeons rely on preoperative CT and MRI scans to orient themselves within a patient's brain during surgery. Once the brain is cut, the tissue shifts, and the scans may no longer be an accurate map. But performing these scans during surgery is impractical. The advantage of the new ultrasound method is that it's done in real time, says K. Kirk Shung, a biomedical engineer at the University of Southern California who isn't involved in the endoscope's development. "CT scans and magnetic resonance imaging are not real time, and are much more expensive."
Two-dimensional ultrasound is already widely used during biopsies to guide surgeons to tumors and during the implantation of devices such as electrodes for deep brain stimulation, says Duke bioengineer Stephen Smith, who developed the ultrasound device. But it's difficult to correlate the flat two-dimensional images with the reality of a patient's 3-D brain. And, Smith says, the existing ultrasound probes require the doctor to drill a large hole--one to two centimeters wide--in a patient's skull. His 3-D ultrasound probe requires a much smaller hole in the skull: less than a centimeter in diameter. Some procedures, such as biopsies or draining cerebrospinal fluid to relieve pressure on the brain, could be done through the same hole using the endoscope.
The Duke researchers tested the 3-D endoscope in dogs to image the vessels that carry the cerebrospinal fluid. They used a needle inserted into the endoscope to drain some fluid and inject a drug. They also tested the device in combination with a contrast agent to see the blood vessels in these dogs' brains in color.
