Diffusion Tensor MR Imaging In Diagnosing Hypoxic-Ischemic Encephalopathy Of Neonates: Initial Experience

PURPOSE: To determine the utility of using quantitative diffusion anisotropy values as an objective means of detection and prognosis of brain injury caused by hypoxic-ischemic encephalopathy (HIE) in term neonates.MATERIALS AND METHODS: Conventional MR images, quantitative diffusion anisotropy MR images, and CT images were obtained from 21 neonates clinically diagnosed as mild HIE and from 9 term neonates as moderate or severe HIE. Mean diffusivity (Da) and fractional anisotropy (FA) and relative anisotropy (RA) were calculated in predefined regions in the two groups of neonates with HIE. A Student t-test was performed for each region and color-coded FA images and three-dimensional color-coded tensor images were reconstructed to compare the mild HIE group with the other group.RESULTS: Da values of the two groups were not significantly different in all regions of interesting (ROIs), while CT and FA and RA values of the two groups were significantly different in the same ROIs. Values of Da and CT showed statistically significant correlations with gestational age. It didn't appeared yellow or red color on color-coded FA images in the neonates with moderate or sever HIE group because of lower FA. It appeared mixed color and thinner in the posterior limb of internal capsules in the neonates with moderate or sever HIE group.CONCLUSION: Quantitative diffusion anisotropy images combined with color-coded FA images and three-dimensional color-coded tensor images can improve conspicuity of hypoxic-ischemic injury. Calculation of anisotropy values can provide an objective measure of hypoxic-ischemic injury to evaluate prognosis as promising MR markers.