Brain death refers to the irreversible end of all brain activity and is usually assessed clinically. However, as this diagnosis allows organ donation for transplantation or withdrawal of life support, most countries have specific related legal standards and practice guidelines 2.
Radiology may be used when clinical tests are impossible to perform, e.g., ocular trauma precluding brainstem function assessment. Most tests rely on the absence of cerebral blood flow as a surrogate for brain death. This can be assessed by a number of modalities including nuclear medicine and catheter angiography.
- diffuse cerebral oedema with effacement of the grey-white matter borders
- CT angiography: non-opacification of the cortical middle cerebral arteries and internal cerebral veins are the most sensitive and specific markers on CTA 3
- T1: hypointense, with lost grey-white matter differentiation
- swollen gyri with hyperintense cortex
- expected flow void may be absent in vessels
- DWI: hemispheric high signal, severe ADC drop
- no forward flow above the terminal ICA
- 1. Huang AH. The hot nose sign. Radiology. 2005;235 (1): 216-7. doi:10.1148/radiol.2351030537 - Pubmed citation
- 2. van der Lugt A. Imaging tests in determination of brain death. Neuroradiology. 2010;52 (11): 945-7. doi:10.1007/s00234-010-0765-7 - Free text at pubmed - Pubmed citation
- 3. Frampas E, Videcoq M, de Kerviler E et-al. CT angiography for brain death diagnosis. AJNR Am J Neuroradiol. 2009;30 (8): 1566-70. doi:10.3174/ajnr.A1614 - Pubmed citation