Bertagna Francesco, Barozzi Ottorino, Puta Erinda, Lucchini Silvia, Paghera Barbara, Savelli Giordano, Panarotto Beatrice, Rodella Carlo Alberto, Rebuffoni Lina, Bosio Giovanni, Terzi Arturo, Giubbini Raffaele
Nuclear Medicine Unit, Spedali Civili di Brescia, 25124 Brescia, Italy.
Nucl Med Commun. 2009 Oct;30(10):815-21. doi: 10.1097/MNM.0b013e32832ff5f8.
In 1968, the Harvard criteria for brain death diagnosis were introduced in clinical practice. These include no movements or breathing, no reflexes, and flat electroencephalogram in the absence of confounding factors, including hypothermia, drugs, electrolyte, and endocrine disturbances. When confounding factors occur, confirmatory tests documenting the absence of cerebral blood flow, such as cerebral angiogram, transcranial Doppler sonography, computed tomography angiography, and nuclear techniques, are required.
The aim of this study was to evaluate the clinical value of single-photon emission computed tomography (SPECT) with technetium-99m (Tc)-ECD in the diagnosis of brain death in a cohort of patients with confounding factors. Fifty-two patients were studied between 1 January 2000 and 23 September 2008. The criteria for the request for Tc-ECD SPECT were sodic thiopental withdrawal after less than 24 h, unreceptivity and unresponsivity of brainstem reflexes, anesthesia in the last 24 h, hypothermia, anamnesis for barbiturate use, electroencephalogram artefacts, toxic state, and pediatric criteria. All patients underwent Tc-ECD SPECT using a dual-headed camera fitted with a high-resolution low-energy collimator. Images were reconstructed and processed according to standard procedures and interpreted qualitatively by two experienced observers.
The presence of spots of residual brain viability was observed in 13 patients: 25% of our patient cohort. The patients with residual viability were younger (aged 30.92+/-17.28 years) in comparison with those with no viability (41.91+/-18.77 years, P<0.031). Considering the eligibility for transplantation, there were 12 of 13 patients in the residual viability group and 31 of 39 in the no viability group (P<0.0001). All patients with spots of brain uptake were monitored daily by Tc-ECD SPECT, and all of them reached the condition of empty skull after one or multiple studies. The opposition to organ donation was observed in six of 13 patients with spots of viable brain tissue and in three of 39 with no signs of residual viability (P<0.001).
In patients with confounding factors in whom brain death diagnosis is equivocal, Tc-ECD SPECT is a helpful and safe diagnostic approach, allowing a three-dimensional evaluation of cortical and brainstem viability. It guarantees an unequivocal diagnosis of brain death for patients who are potential candidates for organ donation. The persistence of viable spots of brain tissue was found in 25% of our patients and was more frequent in young patients. This affects the opposition to donation.
1968年，哈佛脑死亡诊断标准被引入临床实践。这些标准包括无运动或呼吸、无反射以及在无包括体温过低、药物、电解质和内分泌紊乱等混杂因素的情况下脑电图呈平线。当出现混杂因素时，需要进行如脑血管造影、经颅多普勒超声、计算机断层血管造影和核技术等证实无脑血流的确认性检查。
本研究的目的是评估锝-99m（Tc）-ECD单光子发射计算机断层扫描（SPECT）在一组存在混杂因素的患者脑死亡诊断中的临床价值。2000年1月1日至2008年9月23日期间对52例患者进行了研究。请求进行Tc-ECD SPECT检查的标准为硫喷妥钠停药时间少于24小时、脑干反射无反应性和无反应、过去24小时内有麻醉、体温过低、有巴比妥类药物使用史、脑电图伪迹、中毒状态以及儿科标准。所有患者均使用配备高分辨率低能准直器的双头相机进行Tc-ECD SPECT检查。图像按照标准程序重建和处理，并由两名经验丰富的观察者进行定性解读。
13例患者（占我们患者队列的25%）观察到存在残余脑存活斑。与无存活斑的患者（41.91±18.77岁，P<0.031）相比，有残余存活的患者更年轻（年龄30.92±17.28岁）。考虑到移植资格，残余存活组的13例患者中有12例，无存活组的39例患者中有31例（P<0.0001）。所有有脑摄取斑的患者均通过Tc-ECD SPECT每日监测，并且在一次或多次检查后所有患者均达到颅骨空虚状态。在13例有存活脑组织斑的患者中有6例反对器官捐赠，在39例无残余存活迹象的患者中有3例反对器官捐赠（P<0.001）。
在脑死亡诊断不明确且存在混杂因素的患者中，Tc-ECD SPECT是一种有用且安全的诊断方法，可对皮质和脑干的存活情况进行三维评估。它为可能成为器官捐赠候选者的患者保证了明确的脑死亡诊断。我们25%的患者中发现存在存活的脑组织斑，且在年轻患者中更常见。这影响了对捐赠的反对态度。
