不同胎龄新生儿脑代谢物及脑内不同部位体积的研究

Brain metabolites and regional brain volumes of newborns with different gestational ages

目的通过氢质子磁共振波谱（3H MRS）检测不同胎龄新生儿脑代谢物,并应用软件测量磁共振成像（MRI）脑内不同部位体积,探讨不同胎龄新生儿脑代谢物和脑不同部位体积的变化和意义。方法选取2012年8月至2014年9月我院新生儿科收治的无神经系统病变、感染、缺氧、代谢异常等问题的患儿,生后4-7天进行头颅MRI检查,并采用MATLAB和ITKSNAP软件计算大脑、小脑、脑脊液和颅内腔体积,3H MRS测量右侧额叶的代谢物N-乙酰天门冬氨酸（NAA）、胆碱类化合物（Cho）和肌酸类（Cr）波峰下面积,计算NAA/Cr、Cho/Cr和NAA/Cho比值。结果共纳入88例新生儿,胎龄32-33周21例,34-36周26例,37-38周21例,39-41周20例,各组性别和日龄差异均无统计学意义（P〉0.05）。32-33周组、34-36周组、37-38周组和39-41周组新生儿NAA/Cr（0.58±0.10,0.75±0.15,0.76±0.15,0.76±0.11）、NAA/Cho（0.41±0.09,0.47±0.11,0.49±0.10,0.47±0.06）、大脑体积（× 10^4mm^3）（28.2±1.9,29.6±1.6,30.9±2.2,31.7±2.9）、小脑体积（× 10^4mm^3）（1.79±0.11,1.87±0.15,1.94±0.16,2.01±0.26）与颅内腔体积（× 10^4mm^3）（31.7±2.0,33.1±1.7,34.5±2.2,35.3±3.1）组间差异均有统计学意义（P〈0.05）,32-33周组NAA/Cr和NAA/Cho均低于其余3组（P〈0.05）,34-36周组、37-38周组和39-41周组之间差异无统计学意义（P〉0.05）;34-36周组、37-38周组和39-41周组与32-33周组小脑体积差异均有统计学意义（P〈0.05）,39-41周组与34-36周组大脑体积和颅内腔体积差异均有统计学意义（P〈0.05）,37-38周组与34-36周组大脑体积差异有统计学意义（P〈0.05）,37-38周组与39-41周组各部位体积差异均无统计学意义（P〉0.05）。各组Cho/Cr和脑脊液体积差异均无统计学意义（P〉0.05）。NAA/Cr、NAA/Cho、大脑体积、小脑体积和颅内腔体积与体重和胎龄均成正相关,Cho/Cr和脑脊液体积与体重和胎龄无明显相关。结论胎儿脑形态和脑组织内代谢物发育主要在孕32-36周,37周后不明显,故预防早产、加强孕后期营养对胎儿脑形态和神经功能发育很重要。

Objective To detect the brain metabolites and to measure regional brain volumes of newborns with different gestational ages by3 H magnetic resonance spectroscopy（3H MRS） and MRI（ magnetic resonance imaging） plus software,respectively. To investigate the relationship between gestational age（ GA） and brain metabolites / regional brain volumes of newborns. Methods Infants without nervous system lesions,infection,hypoxia,metabolic abnormalities etc. were collected from those admitted to department of neonatology of our hospital from 2012 August to 2014 September. The cerebral MRI examination were taken done 4- 7 days after birth. The volume of cerebrum,cerebellar,cerebrospinal fluid and cranial cavity were calculated by MATLAB and ITKSNAP software. The peak area of the N-acetyl aspartic（ NAA）,choline compounds（ Cho） and creatine compounds（ Cr）- metabolites of right frontal lobe-were measured by3 H MRS,the ratio of Cho / Cr and NAA / Cho,NAA / Cr were also calculated. Results Total of 88 infants were enrolled,with 21 cases of GA 32- 33 weeks,26 cases of GA 34- 36 weeks,21 cases of GA 37- 38 weeks,and 20 cases of GA 39- 41 weeks. Variation of sex ratio and age of days were not significantly different between each GA group（ P〉 0. 05）. The NAA / Cr of each GA group was 0. 58 ± 0. 10,0. 75 ± 0. 15,0. 76 ± 0. 15,0. 76 ± 0. 11,respectively. The NAA /Cho of each GA group was 0. 41 ± 0. 09,0. 47 ± 0. 11,0. 49 ± 0. 10,0. 47 ± 0. 06,respectively. The volume of cerebrum（ × 10^4mm^3） of each GA group was 28. 2 ± 1. 9,29. 6 ± 1. 6,30. 9 ± 2. 2,31. 7 ±2. 9,respectively. The volume of cerebellum（ × 10^4mm^3） of each GA group was 1. 79 ± 0. 11,1. 87 ±0. 15,1. 94 ± 0. 16,2. 01 ± 0. 26,respectively. The volume of cranial cavity（ × 10^4mm^3） of each GA group was 31. 7 ± 2. 0,33. 1 ± 1. 7,34. 5 ± 2. 2,35. 3 ± 3. 1,respectively. The NAA / Cr,NAA / Cho and volume of cerebrum,cerebellar,cranial cavity were all significantly different among GA groups. The NAA / Cr and NAA / Cho of GA group 32- 33 weeks were remarkably lower than those of the other three groups（ P〈 0. 05）,whereas the NAA / Cr and NAA / Cho were not differ significantly among GA groups34- 36 weeks,37- 38 weeks and 39- 41 weeks（ P〈 0. 05）. For the cerebellar volume,except for the difference between 34- 36 weeks group and 32- 33 weeks group,the difference among the 32- 33 weeks group,the 37- 38 weeks group and 39- 41 weeks group all had significant difference（ P〈 0. 05）.The volume of cerebrum and cranial cavity had significant difference between 39- 41 weeks group and34- 36 weeks group（ P〈 0. 05）. For the volume of cerebrum,there was significant difference between37- 38 weeks group and 34- 36 weeks group（ P〈 0. 05）,there was no significant difference between37- 38 weeks group and 39- 41 weeks group（ P〉 0. 05）. The difference of Cho / Cr and cerebrospinal fluid volume between each two groups were not statistically significant（ P〈 0. 05）. The NAA / Cr,NAA /Cho,brain volume,cerebellar volume and intracranial volume were positively correlated with weight and fetal age,the Cho / Cr and cerebrospinal fluid volume were not positively correlated with weight and fetal age. Conclusions The development of fetal brain morphology and the production of brain metabolites occur mainly during 32- 36 weeks of gestation. Therefore,the prevention of preterm delivery and to reinforce the nutrition of late pregnancy are very important for the morphological and functional development of the fetal brain.