Noninvasive assessment of brain injury in a canine model of hypothermic circulatory arrest using magnetic resonance spectroscopy
Noninvasive assessment of brain injury in a canine model of hypothermic circulatory arrest using magnetic resonance spectroscopy
复制标题
DOI：
10.1016/j.athoracsur.2006.01.011
复制
发表时间：
2006-05-01
影响因子：
4.6
通讯作者：
Baumgartner, WA
中科院分区：
文献类型：
--
作者：
Barreiro, CJ;Williams, JA;Baumgartner, WA
背景。研究证实了二氮氧化合物对发生低温循环停止（HCA）的犬的神经保护作用。N-乙酰基-天冬氨酸：胆碱（NAA: Cho）比值的降低反映了神经损伤的严重程度。我们证明，用磁共振波谱法无创测量NAA: Cho有助于评估HCA后的神经元损伤，并允许评估神经保护策略。犬在18℃下进行2小时的HCA，并观察24小时。将动物分为正常（未手术）、HCA（仅HCA）和HCA +二氮氧化合物（HCA前药物治疗）3组，每组15只。HCA后24h，用光谱法测定NAA: Cho比值。立即采集大脑，用质谱法进行新鲜组织NAA定量。HCA组（n = 16）和HCA +二氮氧化合物组（n = 23）分别饲养72小时，每天进行神经学评估。与正常动物相比，HCA的皮质NAA: Cho比值显著降低（1.01 +/- 0.29 vs 1.31 +/- 0.23; p = 0.004），与严重的神经损伤一致。与单独使用HCA相比，二氮氧化物预处理限制了神经损伤，反映在保留的NAA: Cho比值（1.21 +/- 0.27 vs 1.01 +/- 0.29; p = 0.05）。新鲜组织NAA提取证实了数据。与正常相比，HCA组皮质NAA显著降低（7.07 +/- 1.9 vs 8.54 +/- 2.1 mu mol/ g, p = 0.05），二氮氧化合物预处理后NAA水平维持正常（9.49 +/- 1.1 vs 7.07 +/- 1.9 mu mol/ g, p = 0.0002）。与HCA相比，HCA +二氮氧化合物组在所有时间点的临床神经学评分均有显著提高。神经损伤仍然是心脏手术的一个重要并发症，在HCA后最为严重。磁共振波谱法评估NAA: Cho比值提供了一种早期、无创的方法，可以潜在地评估神经损伤和神经保护剂的作用。
Background. Studies have confirmed the neuroprotective effect of diazoxide in canines undergoing hypothermic circulatory arrest ( HCA). A decreased N- acetyl- asparate: choline ( NAA: Cho) ratio is believed to reflect the severity of neurologic injury. We demonstrated that noninvasive measurement of NAA: Cho with magnetic resonance spectroscopy facilitates assessment of neuronal injury after HCA and allows for evaluation of neuroprotective strategies.Methods. Canines underwent 2 hours of HCA at 18 degrees C and were observed for 24 hours. Animals were divided into three groups ( n = 15 in each group): normal ( unoperated), HCA ( HCA only), and HCA + diazoxide ( pharmacologic treatment before HCA). The NAA: Cho ratios were obtained 24 hours after HCA by spectroscopy. Brains were immediately harvested for fresh tissue NAA quantification by mass spectrometry. Separate cohorts of HCA ( n = 16) and HCA + diazoxide ( n = 23) animals were kept alive for 72 hours for daily neurologic assessment.Results. Cortical NAA: Cho ratios were significantly decreased in HCA versus normal animals ( 1.01 +/- 0.29 versus 1.31 +/- 0.23; p = 0.004), consistent with severe neurologic injury. Diazoxide pretreatment limited neurologic injury versus HCA alone, reflected in a preserved NAA: Cho ratio ( 1.21 +/- 0.27 versus 1.01 +/- 0.29; p = 0.05). Data were substantiated with fresh tissue NAA extraction. A significant decrease in cortical NAA was observed in HCA versus normal ( 7.07 +/- 1.9 versus 8.54 +/- 2.1 mu mol/ g; p = 0.05), with maintenance of normal NAA levels after diazoxide pretreatment ( 9.49 +/- 1.1 versus 7.07 +/- 1.9 mu mol/ g; p = 0.0002). Clinical neurologic scores were significantly improved in the HCA + diazoxide group versus HCA at all time points.Conclusions. Neurologic injury remains a significant complication of cardiac surgery and is most severe after HCA. Magnetic resonance spectroscopy assessment of NAA: Cho ratios offers an early, noninvasive means of potentially evaluating neurologic injury and the effect of neuroprotective agents.