Gupta Rakesh K, Saksena Sona, Hasan Khader M, Agarwal Atul, Haris Mohammad, Pandey Chandra M, Narayana Ponnada A
Department of Radiodiagnosis, King George's Medical University, Lucknow, India.
J Magn Reson Imaging. 2006 Sep;24(3):549-55. doi: 10.1002/jmri.20677.
To detect lesion-related focal Wallerian degeneration (WD) changes in different segments of the corpus callosum (CC) in patients with large middle cerebral arterial (MCA) territory stroke using diffusion tensor imaging (DTI).
Eight patients underwent DTI scans at three different time points: six to eight weeks, 10-12 weeks, and beyond six months of stroke onset. Eight healthy age-matched controls were also scanned using the same protocol at three different time points. Region-of-interest (ROI) analysis was performed on seven segments of the CC to determine the fractional anisotropy (FA), mean diffusivity (MD), and corresponding callosal cross-sectional areas.
On repeated-measures analysis of variance (ANOVA), a significant reduction in the FA values was observed from the first to the third study compared to controls, reflecting temporal degeneration in the rostrum, genu, rostral body, anterior midbody, and splenium of the CC. However, a significant temporal elevation in MD values was observed in only the rostral body and anterior midbody of the CC. This was associated with a significant region-specific reduction in the cross-sectional areas at time points beyond six months, and appears to be consistent with the loss of callosal structural components due to interruption of the cortico-callosal fibers secondary to WD.
These results indicate that cortico-callosal topographical changes exhibit a significant temporal decline in observed FA values that is suggestive of cortico-callosal WD in patients with large MCA territory stroke.
利用扩散张量成像（DTI）检测大脑中动脉（MCA）供血区大面积梗死患者胼胝体（CC）不同节段与病变相关的局灶性沃勒氏变性（WD）变化。
8例患者在卒中发作后的三个不同时间点接受DTI扫描：6至8周、10至12周以及卒中发作6个月后。8名年龄匹配的健康对照者也在三个不同时间点采用相同方案进行扫描。对CC的七个节段进行感兴趣区（ROI）分析，以确定分数各向异性（FA）、平均扩散率（MD）以及相应的胼胝体横截面积。
在重复测量方差分析（ANOVA）中，与对照组相比，从首次研究到第三次研究观察到FA值显著降低，这反映了CC的嘴部、膝部、嘴侧体部、前中部和压部的时间性退变。然而，仅在CC的嘴侧体部和前中部观察到MD值有显著的时间性升高。这与6个月后的时间点横截面积出现显著的区域特异性减小有关，并且似乎与由于WD继发的皮质 - 胼胝体纤维中断导致的胼胝体结构成分丧失一致。
这些结果表明，皮质 - 胼胝体的地形学变化表现为观察到的FA值显著的时间性下降，这提示大脑中动脉供血区大面积梗死患者存在皮质 - 胼胝体WD。
