Histopathological study of major intracranial arteries in premature infants related to intracranial hemorrhage.

The incidence of various types of intracranial hemorrhage (ICH) and the microscopic appearance of the major intracranial arteries were investigated in 112 premature infants, and related to birth weight. In none of the premature newborns, regardless of the presence of ICH, did the intracranial arteries contain true elastic elements. The wall of the basilar artery was significantly thinner in all premature infants with any kind of ICH. Within each body-weight group those with ICH had intracranial arteries with fewer reticular fibers than did those without ICH. The density of the reticular fibers in the cerebral arteries of premature neonates without ICH did not seem to depend on maturity. The authors believe that the hypoplasia of the major intracranial arteries and the reticular fiber deficiency most probably involve the whole vascular system of the brain and may predispose to hemorrhage.