Ettl A, Fischer-Klein C, Chemelli A, Daxer A, Felber S
Department of Ophthalmology, University Hospital, Innsbruck, Austria.
Int Ophthalmol. 1994;18(3):171-81. doi: 10.1007/BF00915968.
Magnetic resonance spectroscopy is a valuable method for the non-invasive investigation of metabolic processes and can now be combined with conventional magnetic resonance imaging in patients. This article gives a brief introduction into the principles and physiological and clinical applications of in vivo proton magnetic resonance spectroscopy, surveys experiences in healthy volunteers and presents exemplary results in patients suffering from cortical blindness or visual field defects. The causes of visual loss include brain trauma, cerebral ischemia, and brain tumors. In traumatic, ischemic and neoplastic lesions, an important spectral finding is an elevated lactate resonance which has been explained by increased anaerobic glycolysis of ischemic brain tissue and macrophages invading necrotic tissue. In our investigations using a clinical spectroscopy protocol on a 1.5 T MR system, a significant lactate signal was absent in spectra obtained from the visual cortex of normal volunteers, even during photic stimulation with a stroboscope. Other spectral changes in the patients include a decreased N-acetyl-aspartate resonance which indicates a decreased number of viable neurons in the examined brain region.
磁共振波谱学是一种用于非侵入性研究代谢过程的重要方法，目前可与患者的传统磁共振成像相结合。本文简要介绍了体内质子磁共振波谱学的原理、生理及临床应用，综述了健康志愿者的相关经验，并展示了皮质盲或视野缺损患者的典型结果。视力丧失的原因包括脑外伤、脑缺血和脑肿瘤。在创伤性、缺血性和肿瘤性病变中，一个重要的波谱学发现是乳酸共振升高，这已被解释为缺血脑组织和侵入坏死组织的巨噬细胞无氧糖酵解增加所致。在我们使用1.5T磁共振系统的临床波谱学方案进行的研究中，即使在使用频闪仪进行光刺激时，正常志愿者视觉皮层获得的波谱中也没有明显的乳酸信号。患者的其他波谱变化包括N-乙酰天门冬氨酸共振降低，这表明所检查脑区中存活神经元数量减少。
