体重对早产儿局灶性脑白质损伤类型的影响

Effects of Different Birth Weight on Punctate White Matter Damage in Premature Infants

目的:探讨早产儿不同出生体重和MRI检查时间对局灶性脑白质损伤类型的影响。方法:选取155例MRI表现为T1WI高信号、T2WI低信号、DWI高信号的早产儿(孕周<37周)。根据脑白质损伤的分类方法,将局灶性PWMD类型分为点状损伤(51例)、线状损伤(24例)、簇状损伤(44例)、混合型损伤(36例);按出生体重分为:小于1500g的极低出生体重儿(45例),1500~2500g的低出生体重儿(60例),2500~4000g的正常出生体重儿(50例);按MRI检查时间分为:≤1周(52例),1~2周(57例),>2周(46例)。结果:155例PWMD患儿中,点、线、簇、混合型损伤分别占32.9%(51/155)、15.5%(24/155)、28.4%(44/155)、23.2%(36/155),点状及簇状发生率高,而线状及混合型发生率低。不同出生体重的早产儿在PWMD不同类型之间的差异有统计学意义(P<0.05);损伤部位主要位于双侧脑室前后脚旁、室旁及双侧半卵圆中心区。≤1周、1~2周,>2周时DWI的病灶检出率分别为100%、96.7%、55.2%,而T1WI为92.9%、93.7%、86.9%,DWI病灶检出率高于T1WI序列,且在2周以内做MRI常规联合DWI序列能提高病变的检出率。结论:PWMD在低出生体重早产儿中比较常见,损伤类型以点状最多,线型最少;体重越低,线型损伤的发生率越高;随着体重增加,点状损伤发生率升高;簇状损伤易发生于低出生体重儿中;混合型损伤在极低出生体重儿中所占比例最高;早产儿MRI检查最宜检查时间为生后2周内,DWI能提高病变的检出率。

Purpose： To study the effect of different birth weight and MRI examination time on types of punctate white matter disease （PWMD） in premature infants. Methods： One hundred and fifty-five preterm infants whose MRI characteristics was hyperintensity in T1WI and DWI, hypointensity in T2WI were enrolled. According to the classification of punctate white matter injury, the lesions were divided into focal injury （51 cases）, linear injury （24 cases）, cluster injury （44 cases）, and mixed-type injury （36 cases）. According to the birth weight, they were composed of very low birth weight with body weighting less than 1500g（45 cases）, low birth weight weighting 1500 to 2500g （60 cases） and normal birth weight weighting 2500 to 4000g （50 cases）. According to the MRI examination time, they were divided into less than 1 week （52 cases）, 1 to 2 weeks （57 cases） and more than 2 weeks （46 cases）. Results： Among 155 premature infants diagnosed with PWMD, focal punctate injury, linear injury, cluster injury and mixed-type injury accounted for 32.9% （51/155）, 15.5% （24/155）, 28.4% （44/155）, 23.2% （36/155）, respectively. The incidence of focal and cluster lesions was higher than that of linear and mixed-type. There was statistically significant difference in premature infants bearing with variety of birth weight and PWMD types （P〈0.05）; Lesions were mainly concentrated in the lateral ventricle posterior or anterior, periventricular and centrum semi-oval area. In less than 1 weeks, 1 to 2 weeks, 2 weeks groups, DWI lesions can be detected for 100%, 96.7%, 55.2%, and T1WI for 92.9%, 93.7%, 86.9%. More lesions were detected by DWI than that by T1WI sequence, and combined conventional MRI sequence with DWI within 2 weeks could improve the detection rate. Conclusion： PWMD in low birth weight premature infants were more common. Among all types of injuries, focal injury was the most, linear the least; the lower the weight, the higher the incidence of linear injuries; With the weight gaining, the incidence of focal injuries increased; cluster injury was mainly in low birth weight infants; Mixed-type injury accounted for the highest proportion of very low birth weight infants. The appropriate time for MRI examination in premature infants is within 2 weeks after birth, DWI can improve the detection rate of lesions.