Ventricular dimensions of the brain in premature and full-term infants.

A total of 120 computed tomographic scans of the brain in premature and full-term infants were reviewed. Of these, 28 were judged to exhibit normal ventricular dimensions, and the bifrontal, bicaudate, and bioccipital indices of the lateral ventricles were determined. The bifrontal and bicaudate indices followed a Gaussian distribution, with mean values of 0.28 +/- 0.07 (SD) and 0.15 +/- 0.03 (SD), respectively, whereas the bioccipital index was uniform in its distribution (range, 0.13 to 0.26). For comparison, corresponding indices were determined in scans of ten infants with clinical evidence of hydrocephalus. Based on these data, guidelines are suggested to distinguish normal and abnormal ventricular dimensions in newborn infants.