磁共振弥散成像在弥漫性轴突损伤诊断中的应用

Application of MR diffusion imaging to the diagnosis of diffuse axonal injury

磁共振弥散成像是通过水分子弥散差异成像,反映水分子弥散运动状态。由于成像原理不同于传统磁共振,故弥散成像对中枢神经纤维束的解剖结构改变较为敏感,从而成为弥漫性轴突损伤诊断的重要技术。弥散加权成像能通过突出弥散效应显示损伤灶;弥散张量成像能反映各向异性矢量,更加敏感地显示损伤灶,并可通过神经纤维束成像显示轴突损伤。弥散成像不仅提高了弥漫性轴突损伤的诊断,还有利于判断伤情及预后。该作者对以上问题作一综述。

Magnetic resonance diffusion imaging contrasts by water molecule diffusion, reflecting water diffusion status. Owing to the unique mechanism, diffusion imaging is sensitive to anatomic alteration of fiber tract and becomes an important technique in the detection of diffuse axonal injury. Diffusion-weighted imaging shows DAI lesion via emphasizing diffusion composition, diffusion tensor imaging is more sensitive to diffusion anisotropy of the lesion, and fiber tractography can directly demonstrate fiber disrup- tion. MR-diffusion imaging not only improves conspicuity of DAI, but also has grading and prognostic value.