See that walnut-like object in this brain scan? It's a tumor that needs to be removed. But to avoid damaging critical functions like speech and vision, surgeons have to see the brain's tangled web of connections. The solution? Just add water.
This brain scanning technique, called tractography or diffusion tensor imaging (DTI), has been around for a while now and is used by neuroscientists to investigate and diagnose strokes and conditions like Alzheimer's. But a surgical team from the UC San Diego Health System is the first to use the technique in preparation for surgery.
"The brain can be mapped by tracking the movement of its water molecules," noted neurosurgeon Clark Chen in a UCSD News statement. "Water molecules in brain nerves move in an oriented manner. However, outside the nerves, the molecules move randomly."
The surgeons can use these distinct properties to locate important connections and to guide where surgery should occur — and just as importantly, where they should not occur.
These scans reveal the tiny open paths between nerve fibers to reach brain tumors, and they're color coded to display the intricate neural connections. No other imaging technique — not computed tomography (CT), not magnetic resonance imaging (MRI) — can do this.