Identifying and monitoring traumatic brain injury via Arterial Spin Labeling and MR Elastography

• Applicant: Dr. Christian Thaler
• Subject Area: Clinical Neurology; Neurosurgery and Neuroradiology ; Nuclear Medicine, Radiotherapy, Radiobiology
• Term: from 2017 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 361027488

Traumatic brain injury (TBI) is a diverse and complex injury affecting approximately 268.000 Germans annually. In conventional structural magnetic resonance imaging (MRI) or computed tomography (CT), only severe structural changes reflecting cerebral hemorrhage and tissue damage can be detected. However, especially in sports-related mild TBI (mTBI), functional brain tissue injury is more frequently detected than severe structural injuries. In theory, functional brain tissue injury is pathophysiologically reflected by a variety of changes in metabolic parameters, which remain undetected by conventional imaging techniques that can only be used to diagnose serious injuries such as intracerebral or intracranial hemorrhage or cerebral contusions. Therefore, new MR imaging techniques are needed to diagnose mTBI more accurate and ensure an optimal treatment to reduce long-term deficites.The aim of this study is to measure changes of functional and metabolic parameters before and after traumatic brain injury using advanced MRI techniques like ASL and MRE and correlate these results with the actual impact, measured by accelerometers. We hypothise, that Arterial Spin Labeling (ASL) can indicate functional impairment represented by disturbed cerebral blood flow in affected brain areas whereas routine MRI sequences would not detect any structural pathologies. With this approach, the severity of acute changes as well as outcome parameters can be correlated with the initial impact force and its location to determine the local vulnerability of brain tissue. This information might be of importance in the development of protection gears, identifying areas of the skull, which need more protection than others, leading to adjustment of helmets or enabling monitoring /testing of new equipment.Furthermore, it is planned to use MR elastography to detect changes in brain viscoelastic properties in vivo. The working hypothesis is that mild traumatic brain injuries involve a compression of brain tissue sufficiently altering mechanical properties to generate detectable changes in MRE measurements. Repeated head trauma will, therefore, lead to decreased elasticity of brain tissue. In consequence, less elastic brains are more vulnerable and less shock absorbent and therefore prone to suffer injury after an impact. We hypothesize that elastic brains show less severe acute changes and have a better prognosis after head trauma than less elastic brains. With this method, a risk evaluation for players could be assessed, e.g. before a game, determining whether they might need higher level protective gear or should even refrain from playing because of a significantly increased risk to sustain more severe head injury. Based on the detection of force direction, magnitude, and impact location, an inter-individual comparison of parameters will be possible and parenchymal changes can be related to impact location and severity.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. Max Wintermark