CNRM Research Spotlight: Early MRI detection of Mild TBI
Approximately 85% of all emergency room visits for TBI are diagnosed as mild TBI. Of these patients, the majority fully recover, but for those who do not, life dramatically changes in that they have difficulty returning to normal daily activities and work.
Currently, CT scanning is the imaging method used to assess mild TBI and to guide decision making with regard to further treatment. However, its low incidence of findings in the mild TBI population and lack of evidence for use in all mild TBI patients calls for a better diagnostic that can be used within hours of injury and that is more sensitive to the various subtle changes in the brain following injury. That better diagnostic may be MRI, an imaging method proposed to be sensitive to the changes that occur in a mild TBI.
In the laboratory of CNRM investigator Dr. Lawrence Latour, NIH Stroke Diagnostics and Therapeutics Section, an exploratory study was carried out that determined whether MRI could be used to quickly (within 48 hours of injury) assess mild TBI specific structural changes in an acute setting and to distinguish traumatic from non-traumatic brain pathologies. To address these questions, the study team, led by Dr. Maria Chiara Ricciardi, compared patients with suspected mild TBI to patients with suspected minor acute stroke who presented to the Emergency Department.
The study demonstrated the feasibility of using a short MRI protocol in an acute setting; images taken within 48 hours of injury from 12 of the 22 suspected mild TBI participants showed abnormalities consistent with this type of injury and they were specific to the mild TBI group. Of particular interest is that, of the 19 suspected mild TBI patients who presented with a negative CT scan, 9 had findings on MRI consistent with traumatic injury. In addition, the investigators observed two unique findings in the suspected mild TBI group - enhancement of the meninges on postcontrast FLAIR MRI and linear hypointensities on T2*-weighted MRI - each specific to the mild TBI population. The specificity of these findings to the mild TBI group may point to their utility as imaging biomarkers of TBI pathology and contradicts the prevailing notion that mild TBI cannot be detected on early neuroimaging.
While the size of the study precludes making generalizations, the results are strongly suggestive of the feasibility and utility of using MRI in the acute stage of mild TBI. The study is published in the January 1 volume of the Journal of Neurotrauma. <<pubmed>>
CNRM Research Highlights
Effects of Co-Morbid PTSD on Symptoms of Mild TBI - posted 17 March 2017
Post-traumatic stress disorder is a common co-morbidity of mild TBI in military veterans who served in operations in Iraq and Afghanistan; it is also found to a lesser degree in the civilian population. A number of studies have examined the comorbid effects of PTSD/mild TBI on functional outcomes but none have looked at the effects on brain structure, specifically volume and structural connectivity, or cognitive function. What is apparent is that individuals with co-morbid PTSD/mild TBI do not recover cognitively as quickly as those with mild TBI alone. In a recent article published in the Journal of Neurotrauma, CNRM investigators examined brain volume, structural connectivity, and cognitive function using neuroimaging modalities and neuropsychological testing. The group hypothesized that individuals with PTSD/mild TBI comorbidities would demonstrate changes in brain volume in areas associate with attention and memory as well as differences in memory circuits and these changes would correlate with neuropsychological test results. The team found that individuals with PTSD/mild TBI, when compared to individuals with mild TBI alone, showed a larger volume in the right enterohinal cortex region, a region involved in memory retrieval, as well as white matter alterations in the right cingulum bundle, a white matter tract implicated in facilitating memory suppression processes. These results correlated with poorer performance on neuropsychological tests in the PTSD/mild TBI group compared with the mild TBI group, especially in the areas of learning and memory encoding and retrieval. From the results of this exploratory study, the group postulates that a de-regulated memory retrieval process allows traumatic intrusive memories to interfere with retrieval of those related to the cognitively demanding task at hand, resulting in the poorer scores in the PTSD/mild TBI group. Overall, these results support theoretical models of PTSD and its relationship to learning deficits, and suggest that PTSD patients may benefit from therapies directed toward memory encoding and retrieval problems, as well as associated re-experiencing and avoidance symptoms. <<pubmed>>
Older Veterans with Remote TBI Demonstrate Worse Outcomes in Mulitple Clinical Domains Compared to Veterans with No TBI - posted 1 March 2017
In a study published in the Journal of Head Trauma Rehabilitation, Peltz and collegues, including CNRM investigators, assessed outcomes in elderly veterans with remote TBI compared to those without TBI. Results suggest that veterans with remote TBI fair worse on assessments measuring lifestyle, functional, and psychiatric outcomes as well as global cognition, and executive function/processing speed. Many of these assessment scores were worse on participants who had a history of multiple TBIs and had increasing severity of TBI. <<pubmed>>