Fig. 1

The flow of the internal cerebral vein in case 1. a At 10 hours after birth, the internal cerebral vein (ICV) flow pattern is continuous flat flow (grade 0). b Partially interrupted flow (grade 3) is confirmed at 31 hours after birth with grade III intraventricular hemorrhage (IVH) on the left side. c Partially reversed internal cerebral vein flow (PRF) (arrow) is recognized at 43 hours after birth with grade III bilateral IVH. d PRF is recognized at 90 hours after birth. The lower wave is the forward blood flow of the ICV, and the upper wave is the reverse blood flow of the ICV and the cerebral artery. The temporal relation between the perfusion flow of the cerebral artery and the ICV indicates triphasic venous pulsations constituting an A wave derived from atrial contraction, S wave derived from ventricular contraction, V wave, which corresponds to atrial overfilling, derived from ventricular contraction in the end-systolic phase, and D wave derived from ventricular dilation. The reverse flows are equivalent to A and V waves