Relevance of cerebral microbleeds with leaky blood brain barrier in traumatic brain injury and protective role of interferon-gamma: A cohort study.

Objectives Cerebral microbleeds (CMBs), which present as foci of hypointensities on T2*-weighted Magnetic Resonance Imaging (MRI) are associated with weakened vessel walls. CMBs are also a frequent finding in traumatic brain injury (TBI) in association with poor outcome. We investigated whether a combination of susceptibility weighted imaging (SWI) and dynamic contrast enhanced (DCE) MRI could accurately identify characteristics of CMBs that are most relevant to TBI.Materials And Methods Thirty TBI patients were recruited from a neurosurgical unit. We acquired structural three-dimensional T1-weighted, T2-weighted dark fluid, SWI, and DCE-MRI images on a 3T MRI. DCE-MRI data was fitted for a linear graphic (Patlak-Gjedde) model to calculate voxel-wise volume transfer constant (Ktrans) maps. Ktrans ranges of normal-appearing brain (NAB) areas were quantified and two sub-classes of CMBs-leaky and non-leaky CMBs-were identified. Characteristics and spatial distribution of the quantified imaging metrics and the immunological blood panel results were then compared across mild versus moderate-severe TBI groups, as classified by Glasgow Coma Scale.Results More severe TBI was associated with CMBs exhibiting leaky BBB as quantified by DCE-MRI. Higher blood levels of interferon gamma (IFN-γ) were associated with lower number of CMBs in TBI patients at more than 8 days post-TBI.Discussion combined DCE-MRI and SWI confirmed that CMBs with leaky BBBs are more prevalent in moderate-severe TBIs compared. Higher levels of IFN-γ appeared to have been associated with fewer CMBs in the sub-acute stage of TBI.