New system can sense when the brain is under pressure

Researchers at MIT have developed a technique to calculate brain pressure inside the brains of patients with injuries.

Brain tumors and head trauma, including concussions, can elevate pressure inside the scull that potentially is crushing brain tissue or cutting off the brain's blood supply. Monitoring pressure in the brains of such patients could help doctors determine the best treatment, but the procedure is so invasive it involves drilling a hole through the skull.

That may change with the development of this new technique that is much less risky. The method, described in the April 11 issue of Science Translational Medicine, could allow doctors to measure brain pressure in patients who have suffered head injuries that are milder, but would benefit from close monitoring.

Using this model, the researchers can calculate the brain pressure from two less invasive measurements: arterial blood pressure and an ultrasound measurement of the velocity of blood flow through the brain. This means that brain pressure can be monitored over time, alerting doctors to problems that might build up slowly.

"There's a much larger patient population for whom physicians would like this measurement, but the invasiveness stops them from obtaining it," George Verghese, a professor in electrical engineering, said. His lab focuses on using computer models of human physiology to interpret patient data.

The pressure of blood entering the brain is not directly measurable, so the research team used radial arterial pressure, taken by inserting a catheter at the writs, as proxy for that measurement. Then, they used their model of blood flow to compensate for the difference in location.

Peripheral arterial pressure can also be measured continuously and non-invasively by using a finger cuff similar to the arm cuff commonly used to measure blood pressure. The researchers are now investigating whether data obtained this way is accurate enough to use in their model.

"It's a holy grail of clinical surgery to find a noninvasive way to measure pressure," James Holsapple said, the chief of neurosurgery at Boston Medical Center, "It wold be a big step if we could get our hands on something reliable."

Thomas Heldt, the senior of the paper, said that once the data collection and model are well-established, the team hopes to test different patient populations--such as athletes with concussions, or soldiers who have experienced explosions--to come up with ways to determine the extent of injury and when it is not yet safe for an athlete or soldier to return to the field.

This post was originally published on Smartplanet.com