S I Shiran | PubMed Health

PubMed2002

A prospective, longitudinal diffusion tensor imaging study of brain injury in newborns.

OBJECTIVE: To establish the magnitude and time course of the changes in water diffusion coefficient (D(av)) following newborn infant brain injury. METHODS: Ten newborn infants at high risk for perinatal brain injury were recruited from the neonatal intensive care unit. Conventional and diffusion tensor MRI was performed on three occasions during the first week of life. Regions of injury were determined by evaluating conventional MR images (T1, T2, fluid-attenuated inversion recovery) at 1 week after injury. D(av) values were determined for these regions for all three scans. RESULTS: D(av) values were decreased in most infants 1 day after injury, but injury was not evident or underestimated in 4 of 10 infants despite the presence of injury on conventional imaging at 1 week. By the third day, D(av) values were decreased in injured areas in all infants, reaching a nadir of approximately 35% less than normal values. By the seventh day after injury, D(av) values were returning to normal (pseudonormalization). CONCLUSIONS: MR diffusion images (for which contrast is determined by changes in D(av)) obtained on the first day after injury do not necessarily show the full extent of ultimate injury in newborn infants. Images obtained between the second and fourth days of life reliably indicate the extent of injury. By the seventh day, diffusion MR is less sensitive to perinatal brain injury than conventional MR because of transient pseudonormalization of D(av). Overall, diffusion MR may not be suitable as a gold standard for detection of brain injury during the first day after injury in newborn infants.

Brain Injuries↗

PubMed1998

Normal brain in human newborns: apparent diffusion coefficient and diffusion anisotropy measured by using diffusion tensor MR imaging.

PURPOSE: To establish quantitative standards for the directionally averaged water apparent diffusion coefficient (D) and quantitative diffusion anisotropy (A sigma) of normal brains in newborns by using diffusion tensor magnetic resonance (MR) imaging. MATERIALS AND METHODS: Diffusion tensor MR imaging was performed during the first 36 hours of life in 22 newborns (gestational age range, 31-41 weeks). Values of D and A sigma were measured in regions of interest chosen in the cortical gray matter, centrum semiovale, caudate nuclei, lentiform nuclei, thalami, internal capsules, and cerebellar hemispheres. RESULTS: The D values in the gray and white matter in newborns are considerably higher than those in adults. There is a striking correlation between gestational age and D, with D decreasing as gestational age increases. The A sigma values in the white matter in newborns are lower than those in adults. Values of A sigma show statistically significant correlations with gestational age only in the white matter of the centrum semiovale, in which A sigma values increase sharply near term. CONCLUSION: The D values primarily reflect overall brain water content. The A sigma values are more sensitive to tissue microstructure (e.g., white matter packing and myelination). The D and A sigma images reveal information and not apparent on T1- and T2-weighted images.

Adult↗