Blast-Related Brain Injury: Imaging for Clinical and Research Applications: Report of the 2008 St. Louis Workshop

Abstract

Blast-related traumatic brain injury (bTBI) and post-traumatic stress disorder (PTSD) have been of particular relevance to the military and civilian health care sectors since the onset of the Global War on Terror, and TBI has been called the ''signature injury'' of this war. Currently there are many questions about the fundamental nature, diagnosis, and long-term consequences of bTBI and its relationship to PTSD. This workshop was organized to consider these questions and focus on how brain imaging techniques may be used to enhance current diagnosis, research, and treatment of bTBI. The general conclusion was that although the study of blast physics in nonbiological systems is mature, few data are presently available on key topics such as blast exposure in combat scenarios, the pathological characteristics of human bTBI, and imaging signatures of bTBI. Addressing these gaps is critical to the success of bTBI research. Foremost among our recommendations is that human autopsy and pathoanatomical data from bTBI patients need to be obtained and disseminated to the military and civilian research communities, and advanced neuroimaging used in studies of acute, subacute, and chronic cases, to determine whether there is a distinct pathoanatomical signature that correlates with long-term functional impairment, including PTSD. These data are also critical for the development of animal models to illuminate fundamental mechanisms of bTBI and provide leads for new treatment approaches. Brain imaging will need to play an increasingly important role as gaps in the scientific knowledge of bTBI and PTSD are addressed through increased coordination, cooperation, and data sharing among the academic and military biomedical research communities.

Neural Activation during Response Inhibition Differentiates Blast from Mechanical Causes of Mild to Moderate Traumatic Brain Injury

“…For the milTBI group, five participants (24% of the sample) had been exposed to a single blast event, 8 (38%) reported two blast exposures, and the remaining eight (38%) reported multiple blast exposures (range [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For the civTBI group, six (29%) participants had a history of a single concussion, five (24%) reported two concussions, and eight (38%) reported multiple concussions (range 3-10; data on additional concussions were not available for two participants in this group).…”

“…[1][2][3][4] Epidemiological studies suggest that the prevalence of TBI ranges from 15-28%, 1,5,6 with a majority of these TBIs (50-79%) resulting from blasts caused by improvised explosive devices. 1,7,8 Blast-induced TBI may involve different mechanisms than TBI occurring in civilian settings. Whereas most head trauma in civilians results from mechanical processes such as acceleration/deceleration or rotational forces, 9 blast-induced TBI is thought to result from rapid changes in atmospheric pressure producing overand/or under-pressurization.…”

A Multi-Mode Shock Tube for Investigation of Blast-Induced Traumatic Brain Injury

“…At similar peak overpressures, the difference between the impulses recorded by the reflected and free-field sensors (Benzinger et al, 2009) was greatest for compressed air-driven shockwaves, followed by helium, and were lowest for the oxyhydrogen-and RDX-driven blasts (Fig. 7).…”

“…Positive impulse is the integral of the pressure-time trace, and is related to the linear kinetic energy contained in the blast wave. The impulse difference between reflected and free-field pressures (D Impulse), also a measure of kinetic energy, was calculated by subtracting the positive impulse of the free-field sensor from that of the reflected pressure sensor (Benzinger et al, 2009). …”

Emerging Imaging Tools for Use with Traumatic Brain Injury Research

“…The information extracted is not dissimilar to that obtained from Tc 99 m HMPAO SPECT imaging which is, however, more freely and cheaply available. Limited studies have used FDG-PET in TBI (Benzinger et al, 2009;Hattori et al, 2003Hattori et al, , 2004Kato et al, 2007). O 15 has also been used to measure CBF and oxygen extraction fraction.…”