Werring D J, Clark C A, Barker G J, Miller D H, Parker G J, Brammer M J, Bullmore E T, Giampietro V P, Thompson A J
NMR Research Unit, Institute of Neurology, London, UK.
J Neurol Neurosurg Psychiatry. 1998 Dec;65(6):863-9. doi: 10.1136/jnnp.65.6.863.
Recovery from focal motor pathway lesions may be associated with a functional reorganisation of cortical motor areas. Previous studies of the relation between structural brain damage and the functional consequences have employed MRI and CT, which provide limited structural information. The recent development of diffusion tensor imaging (DTI) now provides quantitative measures of fibre tract integrity and orientation. The objective was to use DTI and functional MRI (fMRI) to determine the mechanisms underlying the excellent recovery found after a penetrating injury to the right capsular region.
DTI and fMRI were performed on the patient described; DTI was performed on five normal controls.
The injury resulted in a left hemiplegia which resolved fully over several weeks. When studied 18 months later there was no pyramidal weakness, a mild hemidystonia, and sensory disturbance. fMRI activation maps showed contralateral primary and supplementary motor cortex activation during tapping of each hand; smaller ipsilateral primary motor areas were activated by the recovered hand only. DTI disclosed preserved structural integrity and orientation in the posterior capsular limb by contrast with the disrupted structure in the anterior limb on the injured side.
The findings suggest that the main recovery mechanism was a preservation of the integrity and orientation of pyramidal tract fibres. The fMRI studies do not suggest substantial reorganisation of the motor cortex, although ipsilateral pathways may have contributed to the recovery. The initial deficit was probably due to reversible local factors including oedema and mass effect; permanent damage to fibre tracts in the anterior capsular limb may account for the persistent sensory deficit. This study shows for the first time the potential value of combining fMRI and DTI together to investigate mechanisms of recovery and persistent deficit in an individual patient.
局灶性运动通路损伤后的恢复可能与皮质运动区的功能重组有关。以往关于脑结构损伤与功能后果之间关系的研究采用了MRI和CT，它们提供的结构信息有限。扩散张量成像（DTI）的最新发展现在提供了纤维束完整性和方向的定量测量。目的是使用DTI和功能MRI（fMRI）来确定右侧囊区穿透伤后发现的良好恢复背后的机制。
对所述患者进行了DTI和fMRI检查；对五名正常对照者进行了DTI检查。
损伤导致左侧偏瘫，数周内完全恢复。18个月后进行研究时，没有锥体肌无力、轻度偏侧肌张力障碍和感觉障碍。fMRI激活图显示，在敲击每只手时，对侧初级和辅助运动皮层被激活；较小的同侧初级运动区仅由恢复的手激活。与受伤侧前肢结构破坏相比，DTI显示后囊肢结构完整性和方向得以保留。
研究结果表明主要的恢复机制是锥体束纤维的完整性和方向得以保留。fMRI研究并未提示运动皮层有实质性重组，尽管同侧通路可能对恢复有贡献。最初的缺陷可能是由于包括水肿和占位效应在内的可逆局部因素；前囊肢纤维束的永久性损伤可能是持续性感觉缺陷的原因。本研究首次展示了将fMRI和DTI结合起来研究个体患者恢复机制和持续性缺陷的潜在价值。
