MRI of cerebral hypoxia

Summary

MRI findings are described in 24 cases of hypoxic coma. In this study hypoxic damage has occurred as a consequence of diverse conditions such as cardiac arrest, anaesthetic accidents, carbon monoxide poisoning, high altitude brain oedema, drowning, suicidal hanging, hypo-glycaemia and shock. The main forms of cerebral damage were watershed infarction and bilateral selective neuronal necrosis within the globus pallidus, putamen, nucleus cau-datus, thalamus, parahippocampal gyrus, hippocampus, cerebellum and brainstem nuclei. Whereas watershed infarction indicated failure of circulation, the pattern of damage within the basal ganglia, thalami, temporal lobe and brain stem could not be related to any of the underlying pathogenetic processes. No typical pattern of lesion could be found in regard to the cause of the disease. However, arterial boundary zone involvement indicates the underlying pathogenetic mechanism. The sensitivity of MRI in the detection of hypoxic lesions was greatly superior to that of CT, while specificity based on signal behaviour allowed differentiation of acute and chronic alterations. Based on serial MRI studies prediction of prognostic outcome will be improved.