功能磁共振成像在脑室旁白质软化症中的应用

fMRI in the Assessment of Cortical Visual Impairment in Children with Periventricular Leukomalacia

通过对24例脑室旁白质软化症(PVL)患儿进行事件相关功能磁共振成像(ER-fMRI)研究,评价fMRI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。选取24例临床确诊为脑瘫的PVL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(ROI),计算患儿与对照组的激活像素数目、HRF曲线幅度以及反应延迟时间,进行配对t检验。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例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。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。

To investigate event- related （ER） functional MRI （fMRI） in the assessment of cortical vi- sual impairment in children with periventricular leukomalacia（PVL）. Twenty - four children who suffered from PVL were included in this study. Meanwhile, 12 age- matched normal controls were recruited for comparison. Slow ER fMRI was performed using a 3.0T MR scanner. Visual stimulus were presented. Data analysis was performed by Statistical Parametric Mapping software （SPM2）, SPM toolbox MarsBar was used to analyse ROI data, and latencies were estimated for surviving voxels using TD and hemody- namic response beta values. A P value of less than 0.05 was considered to indicate statistical signifi- cance. In all 12 normal children, the 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 were shown 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, when compared with normal controls . However, no significant difference of AR was presented when patients and normal controls were compared. The determination of the characteristics of both BOLD response and activation of ER fMRI plays an important role in the cortical visual assessment for children with PVL.