COMPUTED TOMOGRAPHIC ANGIOGRAPHY FOR RAPID DIAGNOSIS OF BRAIN DEATH IN SEDATED PATIENTS
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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.