Towards a Broader Classification of Deep Venous Cerebral Anatomy in Extremely Preterm Infants: A Literature-Based Approach and Its Relevance to Intraventricular Hemorrhage.

BACKGROUND AND PURPOSE

Variability in the deep cerebral venous system is hypothesized to contribute to intraventricular hemorrhage (IVH) in preterm infants. Existing classifications do not adequately capture the range of subependymal venous patterns seen on susceptibility-weighted imaging (SWI) in clinical practice. This study aimed to adapt and expand current classification systems to provide a more comprehensive representation of subependymal vein anatomy in the preterm brain. A secondary aim was to assess maturational changes in venous patterns between 30-and 40-weeks postmenstrual age (PMA) and explore their potential association with GMH-IVH.

MATERIALS AND METHODS

We retrospectively analyzed a cohort of extremely preterm infants (born <28 weeks gestation) who underwent cranial MRI with SWI at both 30-and 40-weeks PMA. In total, 88 infants (176 hemispheres) were included. Images were reviewed to determine subependymal venous configuration and to record germinal matrix hemorrhage (GMH), IVH, or periventricular hemorrhagic venous infarction (PHVI). Based on observed anatomical variations-and informed by historical anatomical descriptions- a novel classification system was developed. Changes in anatomy between the two timepoints were also recorded.

RESULTS

Most frequently observed anatomical pattern (new classification system) was type 1A at 30 weeks PMA (31.3%) and type 1A (26.1%) and 2A (25.6%) at 40 weeks PMA. The change of deep venous anatomy seen on SWI between 30-and 40-weeks postmenstrual age was statistically significant (c=28.11; p=0.005). There was no significant relation between subependymal vein type and change in anatomical pattern. Hemorrhage occurred in 79 hemispheres (48.1% GMH, 39.2% IVH and 12.7% PHVI). There was no significant correlation between GMH-IVH-PHVI and anatomical pattern according to the new classification at 30 weeks PMA, neither between GMH-IVH-PHVI and the change of anatomical pattern between 30-and 40-weeks PMA.

CONCLUSIONS

This study presents a detailed classification of deep cerebral venous anatomy in extremely preterm infants using SWI at 30-and 40-weeks PMA. Despite observed anatomical variability and maturation, no consistent link was found between venous patterns and GMH-IVH or PHVI. This suggests anatomical variation alone may not strongly influence hemorrhagic injury risk, though limited statistical power may affect this conclusion.

ABBREVIATIONS

PMA = Postmenstrual age; GMH = Germinal Matrix Hemorrhage; IVH = Intraventricular Hemorrhage; PHVI = Periventricular Hemorrhagic Venous Infarction.