Kamada K, Houkin K, Hida K, Matsuzawa H, Iwasaki Y, Abe H, Nakada T
Department of Neurosurgery, Hokkaido University, Sapporo, Japan.
Magn Reson Med. 1994 May;31(5):537-40. doi: 10.1002/mrm.1910310510.
Localized proton nuclear magnetic resonance (NMR) spectroscopy of human brain in two common focal pathologies producing brain edema (peritumor edema and acute edematous ischemic stroke) was performed utilizing point resolved spectroscopy (PRESS). The spectra obtained from the pathological tissues were characterized by a reduced N-acetyl-aspartate (NAA) to total creatine (Cr) ratio (NAA/Cr) and high level of lactate. While the spin lattice relaxation time (T1) of the main metabolite resonances, namely, those of NAA, Cr, and choline containing compounds (Cho), showed values similar to those of normal brain, the spin-spin relaxation time (T2) of these metabolites exhibited a dramatic shortening in pathological tissues. Serial postoperative measurements of T2 in two patients with peritumor edema showed a gradual recovery of the T2 shortening corresponding to improvement of the edema. The majority of localized spectroscopy studies in humans is performed using a sequence which utilizes spin echo signals with a fixed single echo time. Hence, the signal intensities of the metabolite resonances obtained are inherently T2 dependent. The current study underscores that cautious interpretation of clinical data with respect to metabolite quantification is warranted.
利用点分辨波谱法（PRESS）对人脑两种常见的导致脑水肿的局灶性病变（肿瘤周围水肿和急性水肿性缺血性卒中）进行了局部质子核磁共振（NMR）波谱分析。从病理组织获得的波谱特征为N-乙酰天门冬氨酸（NAA）与总肌酸（Cr）的比值（NAA/Cr）降低以及乳酸水平升高。虽然主要代谢物共振的自旋晶格弛豫时间（T1），即NAA、Cr和含胆碱化合物（Cho）的自旋晶格弛豫时间，显示出与正常脑相似的值，但这些代谢物的自旋-自旋弛豫时间（T2）在病理组织中显著缩短。对两名肿瘤周围水肿患者术后进行的T2连续测量显示，T2缩短逐渐恢复，这与水肿的改善相对应。大多数针对人类的局部波谱研究是使用一种利用具有固定单回波时间的自旋回波信号的序列进行的。因此，获得的代谢物共振信号强度本质上依赖于T2。当前的研究强调，在代谢物定量方面对临床数据进行谨慎解读是必要的。
