Alternative brain scanning technology may aid diagnosis

Nov 6 2008

Researchers have found new evidence linking losses in memory and attention to subtle forms of brain damage following mild traumatic brain injury (TBI), which may eventually help in diagnosing when a routine concussion might lead to lasting cognitive problems.

TBI affects more than 500,000 Americans each year and over 70 percent of these injuries are considered "mild," usually due to a concussion. Fifteen to 30 percent of these patients will suffer long-term impairments of memory and attention. The findings are published online and in the December issue of the journal BRAIN.

Following a head injury, patients who experience a concussion often show no signs of damage in a traditional CT or MRI scan, pass a basic neurological exam, and are then sent home with no additional treatment or follow-up. However, many such patients continue to report symptoms weeks and even months later, such as loss of concentration or memory loss -- termed post-concussive syndrome.

The researchers studied diffusion tensor imaging (DTI), an advanced type of MRI scan that allows experts to view the microscopic motion of water molecules within the brain's white matter, the tissue that connects and allows communication between different brain centers. The group found that injury was visible in the subjects' memory and attention networks of the brain, but not visible via conventional MRI scans. The team, including researchers from Weill Cornell Medical College and University of California at San Francisco, identified two particular white-matter tracts, one strongly associated with attention and the other memory, in the brains of normal adults and adults with mild TBI.

Dr. Bruce McCandliss, corresponding author and associate professor of psychology in psychiatry at Weill Cornell Medical College, and co-first authors Sumit Niogi of Weill Cornell and Dr. Pratik Mukherjee of UCSF believe that these findings might be the first step toward clinical trials that will determine whether DTI may one day be used for early and accurate diagnosis in patients following TBI.

Since DTI is conducted with an MRI scanner, no additional equipment or cost is needed to collect such data. However, the researchers say that analyzing and interpreting the data is more complex, and tools for clinical diagnosis are still under development.

Contributing authors include Dr. Jamshid Ghajar, Dr. Minah Suh and Rachel Kolster, from Weill Cornell Medical College; and Dr. Geoffrey T. Manley and Hana Lee, from the University of California, San Francisco. The work was funded by a grant from the J.S. McDonnell Foundation.