早产儿大脑发育成熟度早期磁共振成像评估

摘要

目的 分析传统磁共振成像(MRI)图像评估早产儿早期大脑发育成熟度的形态学要点及宏观形态学发育落后的危险因素.方法 选择2013年1月1日至2015年1月1日两家医院新生儿重症监护病房(NICU)收治早产儿的传统MRI图像,根据MRI扫描时间对应的校正胎龄进行分组.利用传统MRI图像的大脑成熟度评分系统(TMS),比较校正胎龄34～41周内大脑发育成熟情况,以及TMS评分与头围评估间的差异;并且通过定量评估脑白质弥漫性高信号(DEHSI),分析DEHSI得分在34～41周内的变化趋势;通过Logistic回归分析探讨低TMS评分的临床危险因素.结果 共纳入校正胎龄34 ～ 41周早产儿图像120例.34 ～ 35周组TMS评分为8.3±0.7,36 ～ 37周组为9.6±1.0,38～ 39周组为11.6±1.4,40 ～41周组为13.6±1.7,各组间比较差异有统计学意义(P＜0.05).皮质卷曲、迁移带得分在各组间均有差异;而38 ～ 39周组与40 ～41周组胚芽基质得分,差异无统计学意义(3.0±0.7比3.3±0.8,P＞0.05),34～35周组与36 ～ 37周组髓鞘化得分,差异无统计学意义(2.4±0.4比2.6±0.5,P＞0.05).各纽DEHSI得分差异无统计学意义(P＞0.05),DEHSI得分与胎龄无明显相关性(r=0.077,P=0.440).以各胎龄段内正常早产儿TMS分值为依据设定达标线.本研究120例早产儿中共68例达标,达标率56.7％.达标组与未达标组头围Z值间,差异无统计学意义.宫内生长迟缓(IUGR)和脑损伤是低TMS评分的影响因素(OR值分别为0.704、12.736,P＜0.05).结论 利用传统MRI图像评估大脑宏观发育成熟度时,应尽量缩小评估胎龄的范围.强调4项指标综合评估,亦需注意各评估指标在不同评估时间窗内的敏感度差异.DEHSI不可作为早期宏观发育形态学成熟度的评估指标.IUGR和脑损伤是早产儿早期大脑发育成熟度落后的影响因素.%Objective To study the early morphological features of brain maturation in preterm infants using conventional magnetic resonance imaging (MRI) and the risk factors of macro-morphological developmental delay.Methods From January 1,2013 to January 1,2015,preterm infants admitted to NICU of our hospital were recruited and their barin MRI images retrospectively reviewed.Infants were assigned into four groups according to their corrected gestational age (cGA) on MRI examination date,including 34-35 w group (cGA 34-35 weeks),36-37 w group,38-39 w group and 40-41 w group.Brain maturation was estimated using total maturation score (TMS) scoring system and head circumferences,and the consistency between the two methods was compared and clinical risk factors of low TMS score were analyzed.Cerebral white matter diffuse excessive high signal intensity (DEHSI) scores for brain maturity evaluation were also studied.Results A total of 120 infants were enrolled in this study.TMS score was 8.3 ± 0.7 in 34-35w group,9.6 ± 1.0 in 36-37w group,11.6 ± 1.4 in 38-39 w group and 13.6 ± 1.7 in 40-41w group.The differences between groups were significant (P ＜ 0.05).Scores of cortical infolding and bands of migrating glial cells were significantly different between these groups while no statistical differences existed in germinal matrix score between 38-39 w group and 40-41 w group (3.0 ± 0.7 vs.3.3 ± 0.8,P ＞ 0.05).The differences myelination score between 34-35 w group and 36-37 w group were not significant neither (2.4 ± 0.4 vs.2.6 ± 0.5,P ＞ 0.05).The DEHSI scores of the four groups were 1.9 ± 0.7,2.0 ± 0.8,2.0 ± 0.7 and 2.1 ± 0.7,and the differences were not significant.TMS score and head circumference were compared on their efficacy for brain maturity evaluation.Only 68 infants (56.7％) reached standard TMS score,while head circumference showed no differences between the infants who reached standard and those didn't.Results of Logistic regression analysis indicated that IUGR and brain injury were the risk factors of low TMS score (OR =0.704,12.736,P ＜ 0.05).Conclusions TMS scoring system is an effective method to evaluate brain maturity.Four indicators,including cortical infolding,bands of migrating glial cells,germinal matrix and myelination should be used together to evaluate brain maturity at different cGA.DEHSI may not be a suitable indicator to estimate the macro-morphology of early brain maturation.IUGR and brain injury are the risk factors for early brain developmental delay in premature infants.