Supplementary Material for: Cerebral Blood Flow Measured by Phase-Contrast Magnetic Resonance Angiography in Preterm and Term Neonates

Background: Preterm infants show a decreased tortuosity in all proximal segments of the cerebral vasculature at term-equivalent age (TEA). Recently MRI techniques were developed to measure cerebral blood flow (CBF) based on phase-contrast images. Objectives: We hypothesized that arterial CBF corrected for brain size differs between full-term and preterm infants at TEA. Methods: 344 infants without major brain abnormalities had a cranial MRI for clinical reasons including phase-contrast magnetic resonance angiography (PC-MRA) around TEA (mean 41.1 ± SD 1.2 weeks). This cohort consisted of 172 preterm infants (gestational age at birth 24.1–31.9 weeks) and 172 term-born infants (gestational age at birth 37.0–42.6 weeks). The total CBF in milliliters/minute was calculated by adding the blood flow of the carotid and basilar arteries, and compared to age at scan, body weight, and several parameters of estimated brain size. Results: After logarithmic transformation, total CBF was associated with body weight, estimated brain weight, head circumference, and 2D brain surface measurements at TEA. Total CBF was significantly (9–12%) higher in term compared to preterm infants after correction for 2D brain surface measurements, head circumference or postmenstrual age at MRI (p < 0.05). Conclusions: Total CBF as measured by PC-MRA was associated with body and (estimated) brain weight and 2D brain surface measurements and was higher in term compared to preterm born infants.研究背景：足月校正年龄（term-equivalent age, TEA）时，早产儿的全脑血管近端段血管迂曲度均有所降低。近年来，学界已开发出基于相位对比影像测量脑血流量（cerebral blood flow, CBF）的磁共振成像技术。 研究目的：本研究假设，在足月校正年龄时，校正脑体积后的动脉脑血流量，在足月儿与早产儿之间存在差异。 研究方法：本研究纳入344名无严重脑部器质性异常的婴儿，因临床诊疗需求于足月校正年龄前后接受颅脑磁共振成像检查，检查项目包含相位对比磁共振血管造影（phase-contrast magnetic resonance angiography, PC-MRA），受试者检查时的平均校正胎龄为41.1±1.2周。该研究队列包含172名早产儿（出生胎龄24.1~31.9周）与172名足月儿（出生胎龄37.0~42.6周）。研究人员通过累加颈总动脉与基底动脉的血流量，计算得到总脑血流量（单位：毫升/分钟），并将该指标与扫描时的校正胎龄、体质量及多项估计脑体积参数进行关联分析。 研究结果：经对数转换后，总脑血流量与足月校正年龄时的体质量、估计脑重量、头围及二维脑表面积测量值均呈显著相关。在校正二维脑表面积、头围或磁共振检查时的经后胎龄后，足月儿的总脑血流量较早产儿显著升高9%~12%（p<0.05）。 研究结论：通过PC-MRA测得的总脑血流量，与体质量、（估计）脑重量及二维脑表面积测量值均呈显著相关，且足月儿的总脑血流量显著高于早产儿。