The role of PET neuroimaging in blast-related traumatic brain injury (TBI)

Learning Objectives Unique challenges facing battlefield injuries and neuroimaging, neuroimaging techniques for diagnosing mild TBI, novel PET agents and TBI.

The impact of Traumatic Brain Injury (TBI) on military servicemembers is significant with more than 300,000 Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) soldiers diagnosed with TBIs. The majority of TBIs are classified as ‘mild’ and the classification criteria for mild TBI is based on the following Department of Defense/Department of Veterans Affairs Clinical Practice Guideline: (1) brief loss of consciousness, (2) brief alteration of consciousness, (3) posttraumatic amnesia for 0 to 1 days, or (4) Glasgow Coma Score of 13-15, and (5) a normal non-contrast brain CT. The extent of mild TBI is not well understood and diagnosis is complicated by the varied symptoms that may also be observed in posttraumatic stress disorder (PTSD). The diffuse and subtle injury is typically not detected on conventional head CT studies and many soldiers are ineligible for magnetic resonance imaging (MRI) due to embedded metal fragments as a result of a blast injury. Early diagnosis and the development of an effective treatment for veterans with TBI is a top priority. Novel neuroimaging techniques using various positron emission tomography (PET) imaging agents may provide critical information for diagnosing and evaluating treaments for TBI. For example, TBI results in abnormalities in brain metabolism and cerebral blood flow, which results in a cascade of subtle changes including inflammation, reduced glucose utilization, transient ischemia, angiogenesis, amyloid plaque deposition, and increased DNA synthesis. Novel PET imaging agents may play an important role in diagnosing TBI. This presentation will discuss the role of PET neuroimaging in TBI along with unique challenges associated with translating bench to bedside in a military population