Department of Biomedical Imaging and Image-Guided Therapy (V.S., G.D., G.G., M.W., M.C.D., M.S.Y., D.P., G.K.).
Division of Neonatology, Pediatric Intensive Care and Neuropediatrics (K.G., K.K.-S., A.B.), Comprehensive Center for Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.
AJNR Am J Neuroradiol. 2021 Mar;42(3):581-589. doi: 10.3174/ajnr.A6945. Epub 2021 Jan 21.
Preterm birth interferes with regular brain development. The aim of this study was to investigate the impact of prematurity on the physical tissue properties of the neonatal brain stem using a quantitative MR imaging approach.
A total of 55 neonates (extremely preterm [=30]: <28 + 0 weeks gestational age; preterm [=10]: 28 + 0-36 + 6 weeks gestational age; term [=15]: ≥37 + 0 weeks gestational age) were included in this retrospective study. In most cases, imaging was performed at approximately term-equivalent age using a standard MR protocol. MR data postprocessing software SyMRI was used to perform multidynamic multiecho sequence (acquisition time: 5 minutes, 24 seconds)-based MR postprocessing to determine T1 relaxation time, T2 relaxation time, and proton density. Mixed-model ANCOVA (covariate: gestational age at MR imaging) and the post hoc Bonferroni test were used to compare the groups.
There were significant differences between premature and term infants for T1 relaxation time (midbrain: < .001; pons: < .001; basis pontis: = .005; tegmentum pontis: < .001; medulla oblongata: < .001), T2 relaxation time (midbrain: < .001; tegmentum pontis: < .001), and proton density (tegmentum pontis: = .004). The post hoc Bonferroni test revealed that T1 relaxation time/T2 relaxation time in the midbrain differed significantly between extremely preterm and preterm (T1 relaxation time: < .001/T2 relaxation time: = .02), extremely preterm and term (T1 relaxation time/T2 relaxation time: < .001), and preterm and term infants (T1 relaxation time: < .001/T2 relaxation time: = .006).
Quantitative MR parameters allow preterm and term neonates to be differentiated. T1 and T2 relaxation time metrics of the midbrain allow differentiation between the different stages of prematurity. SyMRI allows for a quantitative assessment of incomplete brain maturation by providing tissue-specific properties while not exceeding a clinically acceptable imaging time.
早产会干扰大脑的正常发育。本研究旨在采用定量磁共振成像方法研究早产儿脑干部位组织物理特性的改变。
本回顾性研究共纳入 55 例新生儿（极早产儿[=30]：<28+0 周；早产儿[=10]：28+0-36+6 周；足月儿[=15]：≥37+0 周）。大多数情况下，在接近足月时使用标准磁共振方案进行成像。采用 SyMRI 磁共振后处理软件进行多动态多回波序列（采集时间：5 分 24 秒）磁共振后处理，以确定 T1 弛豫时间、T2 弛豫时间和质子密度。采用混合模型方差分析（协变量：磁共振成像时的胎龄）和事后 Bonferroni 检验进行组间比较。
早产儿和足月儿的 T1 弛豫时间（中脑：<0.001；脑桥：<0.001；脑桥基底：=0.005；脑桥被盖：<0.001；延髓：<0.001）、T2 弛豫时间（中脑：<0.001；脑桥被盖：<0.001）和质子密度（脑桥被盖：=0.004）存在显著差异。事后 Bonferroni 检验显示，极早产儿和早产儿的中脑 T1 弛豫时间/T2 弛豫时间存在显著差异（T1 弛豫时间：<0.001/T2 弛豫时间：=0.02），极早产儿和足月儿（T1 弛豫时间/T2 弛豫时间：<0.001），以及早产儿和足月儿（T1 弛豫时间：<0.001/T2 弛豫时间：=0.006）。
定量磁共振参数可区分早产儿和足月儿。中脑的 T1 和 T2 弛豫时间可区分不同阶段的早产。SyMRI 可通过提供组织特异性属性而不超过临床可接受的成像时间来实现对未成熟脑的定量评估。
