事件相关功能磁共振成像在脑室旁白质软化症中的应用

目的：通过对脑室旁自质软化症（PVL）患儿进行事件相关功能磁共振成像（ERIMRI）研究，评价IMRI在缺氧缺血性脑损伤后枕叶视觉区功能变化方面的应用价值。方法：选取24例临床确诊为脑瘫的PVI。患儿，同时选择无窒息史的健康儿童志愿者12例进行对照研究。对这两组儿童进行fMRI检查，fMRI数据采用SPM2软件进行后处理，计算患儿与对照组的激活像素数目、血流动力学响应函数（HRF）曲线幅度以及反应延迟时间，进行配对t检验。结果：正常对照组的激活区位于原始视觉区，BOLD信号变化均为负值，在24名PVL患儿中，枕叶平均激活像素数目减少，4例在PVC区没有激活，6例激活区体积明显减小，7例激活区易位，另有3例激活区明显减小并易位。且HRF曲线都存在不同程度的反应延迟。结论：BOLD和ER—fMRI在评价缺氧缺血性脑损伤后视觉功能变化方面有较高的应用价值。

Usefulness of event-related functional MR imaging in children with periventricular leukomalacia

Objective To investigate event-related functional MR imaging (ER-fMRI) in the assessment of cortical visual impairment in children with periventricular leukomalacia (PVL). Methods Twenty-four children with PVL were enrolled. Meanwhile, 12 age-matched normal controls were recruited for comparison. Slow ER-fMRI was performed using a 3.0T MR scanner. The ROI data analysis was performed by SPM2 software, and latencies were estimated for surviving voxels using time-delay and hemodynamic response function values, t test was used for statistical analysis. Results In all 12 normal children, the blood oxygen level-dependent (BOLD) signal was negative, and the maximum response appeared to be located in the anterior and superior part of the calcarine fissure, which may correspond to the anterior region of the primary visual cortex (PVC). However, in 24 cases of PVL, no activated pixels in PVC in 4; weak and tiny activation in 6; deviated activation in 8; and both tiny and deviated activation in 3 cases. Latencies were delayed in all cases of PVL comparing with normal controls. Conclusion BOLD and ER-fMRI play an important role in the assessment of cortical visual impairment in children with PVL.