MRI定量评估胎儿脑体积

Quantitative assessment of fetal brain volume with MRI

目的观察MRI定量脑体积评估胎儿大脑发育的价值。方法对60例排除胎儿中枢神经系统异常或发育不良、孕周(GA)21~37周的单胎妊娠孕妇行胎儿MR检查,采用单次激发快速自旋回波(SSTSE)序列采集胎儿MRI,经后处理后手动分割大脑,测量胎儿三维脑体积指标颅腔内体积(ICV)、脑总容积(TBV)和脑脊液容积(CFV),计算大脑二维径线指标,包括大脑双顶径(BPD)、骨性双顶径(SBD)、枕额径(SOD)及头围(HC)。分析二维径线指标及三维脑体积指标与GA的相关性,并进行回归分析;观察三维脑体积指标与二维径线指标间的关系。结果TBV(r=0.98)、ICV(r=0.97)、CFV(r=0.89)、BPD(r=0.96)、SBD(r=0.94)、SOD(r=0.96)、HC(r=0.96)均与GA呈高度正相关(P均<0.01)。TBV及ICV与二维径线各指标间均高度正相关(P均<0.01),HC与CFV间亦呈高度相关(P<0.01)。结论MRI三维定量脑体积可较好评估GA 21~37周胎儿颅脑生长发育,有望为产前诊断胎儿脑疾病及研究其发病机制提供新的影像学手段。

Objective To explore the value of MRI quantitative brain volume in evaluating fetal brain development.Methods A total of 60 single pregnant women with 21-37 weeks of gestation without central system lesion or dysplasia underwent fetal single-shot turbo spin echo(SSTSE)sequence MR scanning.The fetal brain images were post-processed,and then fetal three-dimensional brain volume indicators,including intracranial cavity volume(ICV),total brain volume(TBV)and cerebrospinal fluid volume(CFV)were manually measured.Meanwhile,two-dimensional diameter indexes of brain,i.e.brain biparietal diameter(BPD),skull biparietal diameter(SBD),skull fronto-occipitoal diameter(SOD)and head circumference(HC)were measured and calculated.The correlation of two-dimensional diameter indexes and threedimensional brain volume indicators with gestational age(GA)were analyzed,and the corresponding regression analysis was carried out,respectively.The relationships between three-dimensional brain volume indicators and two-dimensional diametric indexes were analyzed.Results TBV(r=0.98),ICV(r=0.97),CFV(r=0.89),BPD(r=0.96),SBD(r=0.94),SOD(r=0.96)and HC(r=0.96)were all highly positively correlated with GA(all P<0.01),and the corresponding regression equations were obtained.There were high positive correlation among TBV,ICV and twodimensional diametric indexes(all P<0.01)and strong correlation between HC and CFV(P<0.01).Conclusion MRI three-dimensional quantitative brain volume can be used to evaluate fetal brain development at 21-37 weeks of gestation,providing a new imaging method for prenatal diagnosis of fetal brain disease and study of pathogenesis.