Karlsborg Merete, Rosenbaum Sverre, Wiegell Mette, Simonsen Helle, Larsson Henrik, Werdelin Lene, Gredal Ole
Department of Neurology, Bispebjerg Hospital, Copenhagen, Denmark.
Amyotroph Lateral Scler Other Motor Neuron Disord. 2004 Sep;5(3):136-40. doi: 10.1080/14660820410018982.
MR diffusion tensor imaging (DTI) appears to be a powerful method to investigate the neuronal and axonal fibre distribution in the human brain. Changes in diffusion characteristics of water molecules in the white matter can be estimated as the apparent diffusion coefficient (ADC) and the fractional anisotropy index (FA).
To characterize DTI changes at three different levels in the corticospinal tract (CST) (corona radiata, internal capsule and pons) in order to elucidate if pathogenesis of ALS is due to an anterograde or retrograde axonal degeneration.
We studied eight ALS patients with clinical signs of upper motor neuron involvement. The patients were compared with 11 healthy age-matched controls.
ADC was significantly increased in the CST in ALS patients at the level of the internal capsule and also increased in the pons, but without statistical significance. ADC was unchanged at the level of the corona radiata. FA was significantly reduced at the lowest level (pons), only tended to be reduced in the internal capsule, but was also unchanged in the corona radiata.
Segmentation of the CST into three regions supports the hypothesis of a 'dying back' mechanism in ALS and suggests that ADC is a more sensitive measure than FA to detect pathological changes in ALS.
磁共振扩散张量成像（DTI）似乎是研究人脑神经元和轴突纤维分布的有力方法。白质中水分子扩散特性的变化可以用表观扩散系数（ADC）和分数各向异性指数（FA）来估计。
描述皮质脊髓束（CST）三个不同水平（放射冠、内囊和脑桥）的DTI变化，以阐明肌萎缩侧索硬化症（ALS）的发病机制是由于顺行性还是逆行性轴突变性。
我们研究了8例有上运动神经元受累临床体征的ALS患者。将这些患者与11名年龄匹配的健康对照者进行比较。
ALS患者内囊水平的CST中ADC显著升高，脑桥中也升高，但无统计学意义。放射冠水平的ADC无变化。FA在最低水平（脑桥）显著降低，仅在内囊有降低趋势，但在放射冠也无变化。
将CST分为三个区域支持了ALS中“回返性死亡”机制的假说，并表明ADC比FA更敏感地检测ALS中的病理变化。
