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Computed tomography angiography (CTA) to prove circulatory arrest for the diagnosis of brain death in the context of organ transplantation.

QUESTION UNDER STUDY
For the determination of brain death (BD) in potential organ donors, confirmatory tests that show cessation of cerebral circulation are used in many countries. Conventional angiography is considered the golden standard among these ancillary examinations. In recent years other angiographic techniques such as CT angiography (CTA) have been increasingly employed to establish the diagnosis of BD. We report our experience with CTA in this setting.


MATERIAL AND METHODS
From 2007 to 2010, 29 patients were examined in order to determine BD using CTA. The studies consisted of an unenhanced head scan, a CT angiogram of the brain supplying vessels in the head and neck and a second head scan 80 seconds after contrast injection (venous phase). The studies were retrospectively re-evaluated by two experienced neuroradiologists according to the criteria accepted by the Swiss Academy of Medical Sciences.


RESULTS
In 22 patients, cessation of cerebral circulation was confirmed in the venous phase CT. In seven patients, cessation of brain circulation was not confirmed due to residual contrast enhancement in the relevant cerebral vessels, i.e. the M4-segments of the middle cerebral artery and/or the internal cerebral veins. In these patients, clinical re-evaluation after a minimum of six hours confirmed the diagnosis of BD. Using the clinical examination as the "golden standard," CTA achieved a sensitivity of 75.9%.


CONCLUSION
CTA is a useful additional tool for the confirmation of the diagnosis of brain death. Pooling of contrast in the relevant cerebral vessels, however, can be detected in up to 25% of CTAs in clinically brain dead patients.