The overwhelming majority of neuropathologic processes associated with
perinatal Insults are related to cerebral blood flow alterations. It
follows that structural ultrasonography is not sufficient and that pul
sed Doppler and color flow Doppler studies should be done to gather he
modynamic data. These ''active ultrasonogram studies'' can suggest an
early diagnosis (hemorrhage, ischemia), provide accurate, immediate pr
ognostic information (ischemia, hydrocephalus), and, in some instances
, lead to preventive therapy (hemorrhage).