Barkovich A J, Westmark K D, Bedi H S, Partridge J C, Ferriero D M, Vigneron D B
Department of Neuroradiology, University of California, San Francisco 94143, USA.
AJNR Am J Neuroradiol. 2001 Oct;22(9):1786-94.
MR techniques have proved useful in assessing brain injury from perinatal asphyxia when the injury is subacute or chronic. Recent advances in understanding the molecular mechanisms of brain injury have made medical intervention plausible, creating a need for assessment of the brain within the first few hours of life. We report the results of early (first 24 hours after birth) MR imaging in seven patients, including proton MR spectroscopy in six.
MR studies were performed within the first 24 hours of life in seven consecutive patients who were encephalopathic after complicated deliveries. Standard T1-, T2-, and diffusion-weighted sequences were performed in all patients; single-voxel MR spectroscopy was performed in two locations in six of the seven patients. Follow-up MR studies were performed in four patients at ages 7, 8, 9, and 15 days, respectively.
T1-weighted images were normal in all seven patients. T2-weighted images were normal in three patients and showed T2 prolongation in the basal ganglia or white matter in the other four. Diffusion images showed small abnormalities in the lateral thalami or internal capsules in all seven patients. Comparison with clinical course in all seven patients and with follow-up MR studies in four showed that the diffusion images underestimated the extent of brain injury. Proton MR spectroscopy showed substantial lactate elevation in all six of the patients studied. Two patients died in the neonatal period and the other five were left with clinically significant neurologic impairment.
MR spectroscopy performed in the first 24 hours after birth is sensitive to the presence of hypoxic-ischemic brain injury, whereas diffusion imaging may help identify but underestimate the extent of the injury. Further studies are ongoing in an attempt to expand upon this observation.
当脑损伤处于亚急性或慢性阶段时，磁共振（MR）技术已被证明在评估围产期窒息所致脑损伤方面很有用。在理解脑损伤分子机制方面的最新进展使得医学干预成为可能，这就需要在出生后的最初几个小时内对脑部进行评估。我们报告了7例患者早期（出生后最初24小时）MR成像的结果，其中6例还进行了质子磁共振波谱分析。
对7例在复杂分娩后出现脑病的连续患者在出生后最初24小时内进行了MR研究。所有患者均进行了标准的T1、T2和扩散加权序列检查；7例患者中的6例在两个部位进行了单体素质子磁共振波谱分析。分别对4例患者在7、8、9和15天时进行了随访MR研究。
7例患者的T1加权图像均正常。3例患者的T2加权图像正常，另外4例患者的基底节或白质T2信号延长。扩散加权图像显示7例患者的丘脑外侧核或内囊均有小的异常。将所有7例患者的扩散加权图像结果与临床病程以及4例患者的随访MR研究结果进行比较，发现扩散加权图像低估了脑损伤的范围。质子磁共振波谱分析显示，所研究的6例患者均有大量乳酸升高。2例患者在新生儿期死亡，另外5例遗留有明显的神经功能障碍。
出生后最初24小时内进行的磁共振波谱分析对缺氧缺血性脑损伤的存在很敏感，而扩散加权成像可能有助于识别脑损伤，但会低估损伤范围。目前正在进行进一步研究以拓展这一观察结果。
