Problem areas in postmortem imaging of the brain

Abstract

Postmortem imaging notably CT, has been embraced in medicolegal death investigation. It allows for non-invasive interrogation of the skull and cranial contents prior to autopsy, forewarning likely findings and excluding overt pathology such as fractures, haemorrhage, and mass lesions. There are, however, deficiencies in postmortem CT in part due to changes to the brain at or after death, and inherent insensitivity to subtle changes in the parenchyma such as early infarction, encephalitis, and low-grade neoplasm. This can in part be rectified by use of postmortem MRI. As in clinical evaluation, postmortem CT and MRI can assist pathologists in understanding cause and mechanism of injury and disease that may not be initially apparent. Examples that will be discussed include: impact of cerebral amyloid angiopathy in traumatic brain haemorrhage; rupture of vessels other than vertebral artery in traumatic basal subarachnoid haemorrhage; venous extradural haematoma; relative contribution of natural disease and trauma in fatal cerebral haemorrhage (so-called chicken v egg); underlying pathology in cases of prolonged hospital stay, hypoxic ischaemic brain injury and status post neurosurgery, by way of forensic interpretation of clinical (antemortem) imaging.