Computed tomographic angiography in the evaluation of brain death

Abstract

According to Polish criteria two neurophysiological methods are used to demonstrate the cessation of brain function: electroencephalography (EEG) and brain stem auditory evoked potentials. Among the techniques measuring cerebral blood flow, conventional angiography of the four cerebral arterial axes is the reference standard for imaging brain death. Thus, it is an invasive examination which needs an experienced neuroradiologist and the availability of an angiography suite. The use of a computed tomographic (CT) scan to diagnose BD was proposed as early as 1978. This exam developed widely these last years thanks to a new generation of multirow CT which allows visualization of opacified cerebral vessels. The aim of the present study was to determine the accuracy of CT-a for the confirmation of BD. We examined four patients with suspicion of BD according to clinical criteria defined by law. CT scan was performed without and with injection of contrast material, followed by cerebral angiography. In our material CT-angiography showed opacification of A2-ACA in two patients (patient 1 and 2). In all our patients the results of CT-angiography fulfill the criteria proposed by the French Society of Neuroradiology in 2007 - absence of perfusion of M4 middle cerebral artery segments (M4-MCA) and deep cerebral veins. In conventional angiography one patient (patient 2) showed, at the level of the anterior and middle cerebral artery, a phenomenon already described as "stasis filling". CT angiography seemes to be a promising radiological exam in the diagnosis of BD. When confirmatory examinations are required among brain-dead patients for whom the clinical diagnosis remains essential, it may be an interesting alternative to conventional cerebral angiography, which is more invasive and constraining, and to EEG when it is unavailable or inadequate