BACKGROUND: The primary construct of the determination of death is that either cardiopulmonary or
neurological function irreversibly ceases. However, there is inconsistency about the validity of neurological
criteria alone for diagnosing brain death especially in sedated patients. This concept considers the need
for more confirmatory tests. PURPOSE: The objective of this study was to discuss the value of brain CT
angiography to provide conclusive evidence of permanent and irreversible loss of brain function. PATIENTS
and METHODS: A total of 28 sedated patients, 21 male and 7 female, mean age 37.5 years presenting
with clinical signs of brain death of different etiologies were studied by multislice CT angiography from
March/2002 to March/2004. The images were reviewed for the presence or absence of intracranial blood
flow and were correlated with the clinical data. RESULTS: Of the 28 brain death clinically diagnosed
patients included in this study; sensitivity of CT angiography was 100% and specificity was 96.5%. In 25
patients (89.2%), the CT angiography showed absence of any intracranial blood flow with circulatory arrest
seen at the V3-V4 vertebral artery level, while interruption of blood flow occurred at different levels of
internal carotid arteries (group 1). In 2 patients (7.2 %), the contrast medium was persistently seen within
the posterior cerebral arteries with no evidence of outflow in delayed CT scan. Internal carotid blood flow
was interrupted below level of foramen magnum in one patient and at level of circle of Willis in the other
patient (Group 2). The last case (3.5%), there was persistent vertebrobasilar circulation (false negative CT
angiographic criteria) although patient was diagnosed clinically dead (group 3). CONCLUSION: Imaging
can be used for establishing the cause of coma, and may be desirable when objective documentation is
needed to substantiate clinical findings, or to shorten the period of observation required before declaring
death. CT angiography appears to be a reliable and simple imaging aid in the diagnosis of brain death. It
should never interpret alone, without considering the clinical signs and various exploratory tests of brain
stem function. |
