MR contrast enhancement of the normal neonatal brain.

PURPOSE To determine the pattern of enhancement on contrast-enhanced MR studies of the brain in neonates.

METHODS Contrast-enhanced brain MR studies of 16 neonates were reviewed retrospectively. All infants had normal neonatal courses, normal noncontrast MR findings, and normal neurologic examinations at age 12 months. All enhancing regions within the brain, dura, calvaria, and orbits were recorded. An enhancement factor, F = (Ic-Ip)/Ip, was calculated from region-of-interest intensity measurements in five regions of each hemisphere (basal ganglia, thalami, and three hemispheric locations), where Ic was signal intensity after contrast administration and Ip was the noncontrast signal intensity for each region.

RESULTS Enhancement was detected in the choroid plexus, pituitary infundibula, pineal glands, dura, veins and venous sinuses, cranial sutures, and irises of the orbital globes. No enhancement of the brain parenchyma was detected by visual inspection, although some change in signal intensity of the cerebral parenchyma was detected by the region-of-interest intensity measurements, with enhancement factors ranging from 0 to 0.08 (mean, 0.04). No consistent regional variation in enhancement was detected. Because the degree of enhancement was identical to that in the normal adult brain, the slight enhancement detected was attributed to contrast material in capillaries and small venules.

CONCLUSION In addition to the expected findings of enhancement of the pituitary stalk, the pineal gland, the choroid plexus, the dura, and the cerebral veins, we detected enhancement of the calvarial sutures and ocular irises. No evidence of enhancement of the cerebral parenchyma was detected, suggesting that the blood-brain barrier to gadolinium chelates is intact in the neonatal brain.