早产儿微小型脑白质损伤的MRI-DTI评价

MRI-DTI evaluation of punctate cerebral white matter damage in preterm infants

目的应用磁共振弥散张量成像(DTI)对不同程度的微小型脑白质损伤(CWMD)进行评价,探讨DTI在早产儿CWMD中的应用价值。方法选取2011年11月至2012年4月住院治疗的31例早产儿,分为局灶性CWMD组11例,广泛性CWMD组10例,同时正常对照组10例,比较三组患儿侧脑室旁的表观弥散系数(ADC)值及各向异性(FA)值,应用Pearson系数检验ADC值及FA值变化的相关性,同时观察三组患儿的彩色FA图。结果局灶性CWMD组及广泛性CWMD组的ADC值均高于正常组,差异有统计学意义。局灶性CWMD组及广泛性CWMD组FA值均低于正常组,广泛性CWMD组FA值低于局灶性CWMD组,差异均有统计学意义。经过后处理的FA彩图提示侧脑室周围白质区域的FA值按正常组、局灶CWMD组及广泛CWMD组顺序依次减低。结论弥散张量成像技术可定量评估微小型CWMD程度。在CWMD评价方面,FA值比ADC值可能更加准确。

Objective To evaluate different degrees of punctate cerebral white matter damage （CWMD） using diffusion tensor imaging （DTI）, and to investigate the value of DTI for CWMD in preterm infants. Methods Thirty-one preterm infants who were hospitalized in the Shengjing Hospital of China Medical University between November 2011 and April 2012 were enrolled and divided into focal CWMD （n=11）, widespread CWMD （n=10）, and normal groups （n=10）. The apparent diffusion coefifcient （ADC） and fractional anisotropy （FA） values were determined in the periventricular regions of patients in three groups, and comparison of the two indices between the three groups was performed using one-way analysis of variance. The correlation between the changes in ADC and FA values was analyzed using the Pearson coefifcient, and the color-encoded FA maps in the three groups were evaluated. Results The ADC values in the focal CWMD and widespread CWMD groups were both signiifcantly higher than in the normal group, while the FA values in the focal CWMD and widespread CWMD groups were both signiifcantly lower than in the normal group. The FA value in the widespread CWMD group was signiifcantly lower than in the focal CWMD group. The color-encoded FA maps after post-processing indicated that the normal group had the highest FA value in the periventricular white matter regions, followed by the focal CWMD group and the widespread CWMD group. Conclusions The DTI technique can quantitatively evaluate the degree of punctate CWMD. The FA value may be more accurate than the ADC value in the evaluation of CWMD.