Pistoia F, Johnson D W, Darby J M, Horton J A, Applegate L J, Yonas H
Department of Radiology, University of Pittsburgh, School of Medicine, Presbyterian-University Hospital, PA 15213.
AJNR Am J Neuroradiol. 1991 Jan-Feb;12(1):97-103.
The demonstration of absent blood flow to the brain is often used as a confirmatory test of brain death. Traditionally, cerebral angiography and dynamic radionuclide brain scanning have been used for this purpose. Recently, xenon CT cerebral blood flow techniques have been developed and applied to a wide variety of clinical problems, including the confirmation of brain death. We report our experience with xenon CT studies performed over a 7-year period (1983-1989) in 30 patients with brain injuries. These patients met clinical criteria for brain death within 24 hr of the study. Twenty patients had average global flow values of less than 5 ml/100 ml/min. Seven patients demonstrated mixed flow patterns, whereby large areas of brain showed flow values of less than 5 ml/100 ml/min and residual pockets of flow greater than 5 ml/100/ml/min. Globally symmetric normal to hyperemic flows were seen in three patients. Our study suggests that the demonstration of average global flows of less than 5/ml/100 ml/min is confirmatory of brain death. Demonstration of persistent flow to the entire brain or regions of the brain is not diagnostic of brain death but also does not exclude such an outcome in patients with severe brain injuries. Xenon-derived flow information may be clinically useful in determining the patient's prognosis and in counseling the patient's family.
脑血流缺失的证明常被用作脑死亡的确证性检查。传统上，脑血管造影和动态放射性核素脑扫描一直用于此目的。最近，氙CT脑血流技术已得到发展，并应用于包括脑死亡确认在内的各种临床问题。我们报告了在7年期间（1983 - 1989年）对30例脑损伤患者进行氙CT研究的经验。这些患者在研究的24小时内符合脑死亡的临床标准。20例患者的平均全脑血流量值低于5毫升/100毫升/分钟。7例患者表现出混合血流模式，即大面积脑区的血流值低于5毫升/100毫升/分钟，而残留血流区的血流值大于5毫升/100毫升/分钟。3例患者全脑呈现对称的正常至充血性血流。我们的研究表明，平均全脑血流量低于5毫升/100毫升/分钟可确证脑死亡。全脑或脑区持续有血流并不诊断为脑死亡，但也不排除重度脑损伤患者出现这种结果。氙衍生的血流信息在确定患者预后和向患者家属提供咨询方面可能具有临床实用性。
