Neuroimaging clinics of North America
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Neuroimaging Clin. N. Am. · Feb 2018
ReviewFunctional MR Imaging: Blood Oxygen Level-Dependent and Resting State Techniques in Mild Traumatic Brain Injury.
This article discusses mild traumatic brain injury (mTBI)-associated effects on brain functional connectivity assessed via resting-state functional MR (fMR) imaging. Several studies have reported acute post-injury default mode network hyperconnectivity, followed by a period of decreased connectivity before later connectivity normalization in some patients. Other studies have reported mTBI associated effects on connectivity that remain evident for up to 5-years or more. Discordance in the published literature regarding the direction of network connectivity changes (eg, increased versus decreased connectivity) may reflect differences in timing of data collection post-injury, as well as the need to standardize MR imaging acquisition protocols and processing methods.
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Conventional imaging findings in patients with cerebral concussion and chronic traumatic encephalopathy are absent or subtle in the majority of cases. The most common abnormalities include cerebral volume loss, enlargement of the cavum of the septum pellucidum, cerebral microhemorrhages, and white matter signal abnormalities, all of which have poor sensitivity and specificity. Advanced imaging modalities, such as diffusion tensor imaging (DTI), blood oxygen level dependent functional MR Imaging (BOLD fMRI), MR spectroscopy, perfusion imaging, positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetoencephalography detect physiologic abnormalities in symptomatic patients and, although currently in the investigation phase, may become useful in the clinical arena.
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Myelin water imaging (MWI) provides mild traumatic brain injury (mTBI) researchers with a specific myelin biomarker and helps to further elucidate microstructural and microarchitectural changes of white matter after mTBI. Improvement of scanner hardware and software with the implementation of MWI across scanner platforms will likely result in increased research regarding the role of myelin in traumatic brain injury (TBI). Future research should include detailed investigation of myelin between 2 weeks and 2 months after injury, the use of MWI in moderate and severe TBI, and investigation of the role of myelin in chronic TBI.
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Conventional neuroimaging examinations are typically normal in concussed young athletes. A current focus of research is the characterization of subtle abnormalities after concussion using advanced neuroimaging techniques. ⋯ In the future, such biomarkers will likely provide important clinical information regarding the appropriate time interval before return to play, as well as the risk for prolonged postconcussive symptoms and long-term cognitive impairment. This article discusses results from advanced imaging techniques and emphasizes imaging modalities that will likely become available in the near future for the clinical evaluation of concussed young athletes.
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Neuroimaging Clin. N. Am. · Feb 2018
ReviewDefinition of Traumatic Brain Injury, Neurosurgery, Trauma Orthopedics, Neuroimaging, Psychology, and Psychiatry in Mild Traumatic Brain Injury.
Traumatic brain injury (TBI) disrupts the normal function of the brain. This condition can adversely affect a person's quality of life with cognitive, behavioral, emotional, and physical symptoms that limit interpersonal, social, and occupational functioning. ⋯ Patients with TBI require prompt evaluation and multidisciplinary management. Aside from the type and severity of the TBI, recovery is influenced by individual patient characteristics, social and environmental factors, and access to medical and rehabilitation services.