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.