Kurtek R W, Lai K K, Tauxe W N, Eidelman B H, Fung J J
Department of Radiology, University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center, Pennsylvania 15213, USA.
Clin Nucl Med. 2000 Jan;25(1):7-10. doi: 10.1097/00003072-200001000-00002.
Diagnosing brain death is important in managing the comatose patient for whom the continuation of life support is being questioned and when organ harvesting is being considered. The virtual immediate localization of Tc-99m HMPAO to cerebral and cerebellar tissue provides an index of blood perfusion, and its absence denotes brain death. Other methods for assessing brain death include cerebral angiography, MRI, CT imaging after inhalation of stable xenon, electroencephalography, and clinical examination. The contrast material used for angiography may damage harvested organs, and the other studies have significant errors. MRI, CT imaging, and angiography are unsuitable for bedside use.
Twenty-three patients, who presented with head trauma, prolonged anoxia or intrinsic brain disease (e.g., glioblastoma multiforme) and who were brain-dead by clinical examination criteria, were referred to the nuclear medicine division for verification of brain death. For adults, approximately 25 mCi Tc-99m hexamethylpropylene amineoxime (HMPAO) was administered intravenously. All patients but one were imaged using a mobile scintillation camera at the bedside.
We demonstrated (1) both cerebral and cerebellar perfusion, (2) neither cerebral nor cerebellar perfusion, (3) cerebral without cerebellar perfusion, and (4) cerebellar without cerebral perfusion. Patients without cerebral perfusion were diagnosed as brain-dead. The significance of a viable cerebellum in the absence of cerebral viability was not fully appreciated, although organs were harvested from such patients. We determined how well the clinical examination criteria held up in the diagnosis of brain death against the new gold standard of Tc-99m HMPAO scintigraphy: Clinical examination criteria correctly predicted brain death only 83% of the time compared with HMPAO scintigraphy.
Brain death assessment by Tc-99m HM-PAO scintigraphy has proved to be a reliable, safe, and cost-effective bedside method and may have practical application in the assessment of brain death in potential cadaveric donors.
对于那些生命支持措施是否继续存在疑问以及正在考虑进行器官摘取的昏迷患者，诊断脑死亡至关重要。锝-99m六甲基丙烯胺肟（Tc-99m HMPAO）在脑和小脑组织中的虚拟即时定位可提供血流灌注指标，其缺失则表示脑死亡。评估脑死亡的其他方法包括脑血管造影、磁共振成像（MRI）、吸入稳定氙气后的CT成像、脑电图以及临床检查。用于血管造影的造影剂可能会损害摘取的器官，而其他检查存在显著误差。MRI、CT成像和血管造影不适合在床边使用。
23例因头部外伤、长时间缺氧或原发性脑部疾病（如多形性胶质母细胞瘤）就诊且经临床检查标准判定为脑死亡的患者被转至核医学科进行脑死亡的核实。对于成年人，静脉注射约25毫居里的Tc-99m六甲基丙烯胺肟（HMPAO）。除1例患者外，所有患者均在床边使用移动闪烁相机进行成像。
我们观察到（1）脑和小脑均有灌注，（2）脑和小脑均无灌注，（3）脑有灌注而小脑无灌注，（4）小脑有灌注而脑无灌注。无脑灌注的患者被诊断为脑死亡。尽管从此类患者身上摘取了器官，但在脑无存活能力的情况下小脑仍存活的意义尚未得到充分认识。我们确定了临床检查标准在与Tc-99m HMPAO闪烁扫描这一新的金标准相比时，对脑死亡诊断的符合程度：与HMPAO闪烁扫描相比，临床检查标准仅在83%的时间内正确预测了脑死亡。
Tc-99m HM-PAO闪烁扫描评估脑死亡已被证明是一种可靠、安全且经济高效的床边方法，可能在潜在尸体供体的脑死亡评估中具有实际应用价值。
