Up until now it has not been possible to visualize the effects of mild TBI on an MRI scan because standard MRI only picks up significant damage to brain tissue. However a new technique using MRI following injection of dye can demonstrate tiny holes in the meninges caused by a concussion, because the dye leaks through the holes. The meninges are the three thin membranes which snugly wrap the outside of the brain. Their job is to hold the brain in place, cushion the brain from minor shock, and keep out harmful molecules. The meninges contain an intricate set of blood vessels and nerves. It was established long ago that concussion can cause severe, post-traumatic headache by dilating blood vessels in the meninges and stretching the nerves that wrap around those vessels.
The new technique was developed by an ingenuous senior at Stanford University named Theo Roth who is majoring in biology. His work with humans (which was published online in the Journal Nature on December 8, 2013) derived from years of experimentation with mice in which Roth used a surgically implanted micro-camera to record the effects of concussion on mice brains in real time. Roth’s work was sponsored and made possible by Dorian McGavern’s lab at the National Institute of Neurological Disorders and Stroke (NINDS). Roth explains that when a concussion causes holes in the meninges it has damaged meningeal cells which leak internal substances (in particular something called reactive oxygen species) that are toxic to cells in the underlying brain tissue.
In the article in Nature Roth worked with co-scientist Lawrence Latour to examine 142 patients who have recently suffered a concussion but whose initial MRI scans had not revealed any physical damage to the brain tissue. Many of these patients were sent home from the hospital with the negative scans, but had since suffered headaches, memory loss or other hallmark symptoms of a mild brain injury. Latour injected the patients with a dye and conducted a follow-up MRI scan; in 49 percent of these patients, Latour saw the dye leaking through the meninges. This new technique is a true breakthrough for people suffering from mild TBI who are not believed by family, treating physicians or – in the case of litigation – by liability insurance companies and their defense lawyers.