Using computed tomography of the brain to correlate low white-matter attenuation with early gestational age in neonates.

Computed tomographic brain scans of the newborn exhibit relatively greater lucency of white matter compared to the mature patient. This study correlated the x-ray attenuation of white matter with gestational age in 23 neonates, both premature and term. The gray-white matter attenuation difference was calculated and plotted versus advancing gestational age. An inverse correlation was found between the gray-white matter density difference and advancing gestational age. Statistical analysis revealed that this phenomenon is due to increasing white matter density in the first months of life with the gray matter showing no significant variation with advancing age. The low attenuation value of white matter in the perinatal period and its subsequent increase is a normal phenomenon; it correlates with the greater water and lower protein content of premyelinated white matter initially, followed by subsequent water loss and protein gain with myelination. Since transient cerebral edema due to hypoxia exhibits similar low attenuation with CT, it is difficult to exclude this entity in the premature infant group where accurate neurologic evaluation is hard to obtain.