Zhang Xiao-Xue, Yin Le-Kang, Hao Xiao-Zhu, Tian Jia-Qi, Li Chan-Chan, Feng Xiao-Yuan, Yang Yan-Mei
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China.
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China.
J Stroke Cerebrovasc Dis. 2017 Jan;26(1):42-48. doi: 10.1016/j.jstrokecerebrovasdis.2016.08.026. Epub 2016 Sep 29.
The purpose of our study is to explore the relationship between recovery of neural function and transformation of the internal capsule (IC) after transient middle cerebral artery occlusion (MCAO) by using diffusion kurtosis imaging (DKI).
Six male adult Sprague-Dawley rats implemented with transient MCAO were used in this study. Sensorimotor function was assessed according to repetitive behavioral testing on day 1, 3, 7, 14, and 28 after cerebral ischemia. Metrics of DKI were acquired, and the time course of the region-to-normal ratio was evaluated in IC.
After cerebral ischemia, relative fractional anisotropy in IC decreased on day 3 (P < .01). Relative mean diffusivity (rMD) increased on day 28 (P < .05). Relative mean diffusional kurtosis (rMK) increased on day 3 (P < .01) and decreased on day 7 (P < .05). Relative axial diffusional kurtosis (rKa) increased on day 3 (P < .01) and declined on day 7 (P < .05). Relative radial diffusional kurtosis (rKr) was reduced on day 7 (P < .05). Changes in rMK were larger than changes in rMD on day 3 (P < .05). The factor of rKa and rKr revealed marked difference on day 7 (P < .05) and day 14 (P < .05). Neurological function score showed that rats exhibited functional recovery from day 7 (P < .01) post stroke.
This longitudinal multiparametric magnetic resonance imaging study suggested that K metrics offers information complimentary to conventional diffusion metrics and revealed the procedure during the structural modification in the ipsilateral IC following focal cerebral ischemia. After transient MCAO, the neural transformation occurred in a time-dependent procedure.
本研究旨在利用扩散峰度成像（DKI）探讨短暂性大脑中动脉闭塞（MCAO）后神经功能恢复与内囊（IC）变化之间的关系。
本研究使用6只实施短暂性MCAO的成年雄性Sprague-Dawley大鼠。在脑缺血后第1、3、7、14和28天，根据重复性行为测试评估感觉运动功能。获取DKI指标，并评估IC中区域与正常比值的时间进程。
脑缺血后，IC的相对分数各向异性在第3天降低（P <.01）。相对平均扩散率（rMD）在第28天增加（P <.05）。相对平均扩散峰度（rMK）在第3天增加（P <.01），在第7天降低（P <.05）。相对轴向扩散峰度（rKa）在第3天增加（P <.01），在第7天下降（P <.05）。相对径向扩散峰度（rKr）在第7天降低（P <.05）。第3天rMK的变化大于rMD的变化（P <.05）。rKa和rKr因子在第7天（P <.05）和第14天（P <.05）显示出显著差异。神经功能评分显示，大鼠在中风后第7天开始出现功能恢复（P <.01）。
这项纵向多参数磁共振成像研究表明，峰度指标提供了与传统扩散指标互补的信息，并揭示了局灶性脑缺血后同侧IC结构改变的过程。短暂性MCAO后，神经变化呈时间依赖性过程。
