Weekly serial CT brain scans of the nine surviving infants with a grade Ill or grade IV hemorrhage demonstrated progressive ventricular dilatation (fig. 6) in eight (89%). Developing hydrocephalus was evident on CTscans before the development of an abnormal increase in head circumference. Early detection of ventricular dilatation by CT allowed early institution of appropriate therapy. In the three surviving infants in whom the initial germinal matrix hemorrhage extended into the brain parenchyma (grade IV), serial scans showed residual areas of paraventricular porencephaly, often of considerable size (fig. 7).