Advances in imaging studies of contusion penumbra

Traumatic brain injury (TBI) is a serious human health hazard. The contusion penumbra (CP) is the area of injury that lies between the core of the injury and normal-looking brain tissue. CP is the main site where secondary injury occurs. Additionally, it offers a major therapeutic target for preserving neurological function post-TBI. Using different imaging modalities, specific cellular and tissue changes in CP as well as contusion core and surrounding normal brain tissue were evaluated. Even though the existing imaging techniques are widely used in clinics, these techniques often do not characterize the cellular and histopathological changes in the CP accurately. The fundamental absence of uniform assessment criteria can lead to inconsistent clinical decisions, which would not be favourable to patients. As such, improving imaging techniques will be important to truly reflect better the changing pathophysiology of the CP. Revising these techniques could allow for more homogeneous clinical results and improve therapeutic decision making to enhance health outcomes in neurology. We conducted a comprehensive review of literature on the abilities and limitations of imaging methods used in CP studies.