How should we use imaging in the determination of brainstem death?

Brainstem death is defined as the "irreversible cessation of brainstem function", either due to primary intracranial events or extracranial factors such as hypoxia. The importance of accurate and timely diagnosis of brainstem death in critical care should not be understated, as it allows the withdrawal of treatment when it is no longer deemed to beneficial. Additionally, it may facilitate the process of organ donation. Overall, the diagnosis of brainstem death has four common principles across the world: (1) neurological criteria based on clinical assessment; (2) evidence of irreversible brain damage from known aetiology; (3) demonstrating an absence of a reversible cause; and (4) the use of ancillary studies. The latter in particular has been a controversial issue, with much debate continuing on how imaging should be used. We discuss three key questions surrounding the role of imaging in the diagnosis of brainstem death as well as important issues the radiology community should consider.