Regional impairment of cortical and deep gray matter perfusion in preterm neonates with low-grade germinal matrix-intraventricular hemorrhage: an ASL study

Purpose: The long-term impact of low-grade germinal matrix-intraventricular hemorrhage (GMH-IVH) on brain perfusion has not been fully investigated. We aimed to compare cortical and deep gray matter (GM) cerebral blood flow (CBF) obtained with pseudo-continuous arterial spin labeling (pCASL), among preterm neonates with and without low-grade GMH-IVH and full-term controls. Methods: 3T-pCASL examinations of 9 healthy full-term neonates (mean gestational age 38.5 weeks, range 38–39) and 28 preterm neonates studied at term-equivalent age were analyzed. Eighteen preterm neonates presented normal brain MRI (mean gestational age 30.50 weeks, range 29–31) and 10 low-grade GMH-IVH according to Volpe’s grading system (mean gestational age 32 weeks, range 28–34). A ROI-based mean CBF quantification was performed in 5 cortical (frontal, parietal, temporal, insula, occipital), and 4 subcortical GM regions (caudate, putamen, pallidum, thalamus) for each cerebral hemisphere. CBF differences were explored using a nonparametric analysis of covariance. Results: Low-grade GMH-IVH hemispheres showed consistently lower CBF in all GM regions when compared with healthy preterm neonates, after controlling the confounding effect of gestational age, postmenstrual age, and birth weight P <.001, η2 =.394. No significant differences were observed between neonates with low-grade GMH and full-term controls. Healthy preterm neonates showed significantly higher CBF than full-term controls in parietal (P =.032), temporal (P =.016), and occipital cortex (P =.024), and at level of thalamus (P =.023) and caudate nucleus (P =.014). Conclusion: Low-grade GMH-IVH is associated with lower CBF in posterior cortical and subcortical gray matter regions in preterm neonates, suggesting regional vulnerability of these developing brain structures.