Simulated intracranial conductivity image following hemorrhagic injury with blood shown as a region of high conductivity. Impedance data recorded from eight scalp electrodes (not shown) and one intracranial electrode (central purple dot).

"By combining electrical impedance sensing with a conventional pressure sensor," writes ASME, "Dartmouth engineer Ryan Halter is creating an early warning system that may help doctors treat traumatic brain injuries before they permanently damage the brain.

"Some 1 million people suffer traumatic brain injuries annually. In the most severe cases, internal bleeding increases pressure on the brain, which chokes off blood circulation and can be debilitating or fatal.

"Before turning to brain injuries, Halter, an assistant professor at Dartmouth's Thayer School of Engineering, had spent years developing electrical impedance sensors to image cancer noninvasively. This changed when a graduate student's father, a neurosurgeon, asked if impedance sensing could measure changes in blood flow. Halter realized that measuring the impedance of blood in the brain might alert clinicians to pressure increases inside the skull earlier than existing sensors.

"'I would hope that our technology, or other imaging technologies, can better determine intracranial health after an injury,' Halter said.

"He has a patent and is developing the technology through his startup company, RyTek Medical. 'Our long-term goal is to better monitor mild and moderate traumatic brain injuries,' he said. 'Initially, however, we are going to target patients with severe traumatic brain injuries.'"

Much of this work has grown from a collaboration between Halter and former PhD student Preston Manwaring Th'13 who is an integral part of the current tech development team. Manwaring's thesis research investigated "A Novel Multimodal Imaging Device for Traumatic Brain Injury," and he was a member of the first class of graduates from Dartmouth's PhD Innovation Program: