Introduction: According to the major hypothesis distortions in CBF is one of the substantial factors in the etiology and pathogenesis of cerebral damage in the neonate. To estimate the flow to the subcortical white matter we have examined regional cerebral blood flow in twelve preterm infants.

Patients: 12 healthy preterm infants with normal ultrasonographic examination and without sign of cerebral damage (median gestational age 27.7 weeks).

Methods: Single photon emission computer tomography and99m Tc-HMPAO. In 5 infants correction for scattered radiation was possible.

Results: Blood flow to the subcortical white matter relative to the average cerebral blood flow was without correction for scattered correction 0.53 (0.48-0.58). With correction the flow was 0.37 (0.35-0.4)(mean and 95%-confidence limits).

Conclusion: In preterm infants the global CBF is 15.5ml/100g/min. and thus the flow to the white matter is 5.8 (4.4-6.2)ml/100g/min. The threshold to maintain neuronal viability in the white matter is likely below 1.9 (1.8-2.0)ml/100g/min.