Table V shows magnetic resonance imaging (MRI) neuroimaging techniques. Nevertheless, significant challenges exist, in terms of summarizing existing findings and translating data to improve clinical practice. Studies often involve diverse cohorts (eg, mild TBI, combat, veterans), and employ different paradigms (symptom provocation, cognitive activation) and modalities (eg, diffusion tensor imaging [DTI], functional magnetic resonance imaging [fMRI],

single photon emission computed tomography [SPECT]).50 As such, findings have varied. Peskind and colleagues noted that Inhibitors,research,lifescience,medical fluorodeoxyglucose positron emission tomography (FDG-PET) abnormalities in those with PTSD versus those without this disorder have been “limited and conflicting” (p 5).51 In terms of validation, experiments supporting newer functional imaging techniques often rely on neuropsychological paradigms. For example, in response to findings regarding Inhibitors,research,lifescience,medical the positive relationship between DTI results and neuropsychological test performance among those with mild, moderate, and severe injuries, Kraus ct al3 suggested that white matter load may be a “useful index.“ Much work is being conducted to support, these new imaging techniques, and findings are

increasing our knowledge regarding those with TBI and/or PTSD. Table V. Magnetic resonance imaging (MRI) Inhibitors,research,lifescience,medical neuroimaging techniques. BOLD, blood oxygen level dependent; DTI, diffusion tensor imaging, fMRI, functional MRI; MRS, magnetic resonance spectroscopy; PW-MRI, perfusion weighted MRI; SWI, susceptibility-weighted imaging … TBI Although newer techniques have begun to allow clinicians to explore questions regarding pathogenesis, natural history, neuroplasticity, and treatment, response,52 historically, neuroimaging has been used to identify Inhibitors,research,lifescience,medical and manage acute modcratc-to-sevcre TBI. Less sophisticated structural imaging techniques such as computed tomography (CT) or MRI have been useful in identifying skull fractures or more severe injuries (eg contusion, intraparaenchymal hemorrhage); however, they generally fail to adequately Inhibitors,research,lifescience,medical detect DAI or brain volume loss. Moreover, in combat, or deployment,

settings these generally common diagnostic tools may not be available isothipendyl to the clinician.53 Research among both Veteran and civilian populations suggests that, use of CT and MRI has limited utility in confirming acute or post-acute mild TBI.54-56 In looking at MRI results of veterans long postTBI, Brenner and colleagues55 found that those with Alvespimycin moderate to severe TBI were significantly more likely to have trauma-related findings (physical) than those with mild TBI. In specific, 11 out of 16 veterans with moderate to severe TBI versus 0 out 16 with mild TBI had MRI findings. Research regarding newer functional imaging techniques (eg, FDG-PET, DTI, SPECT) suggests that in the future they may be of significant clinical utility, particularly in the context of mild TBI and/or post-acute injuries.