Evolution of MR DTI changes in neonatal rats after mild hypoxic-ischemic insult

Abstract

7-day-old mild hypoxic-ischemic (H-I) rats (n=12) were studied at 7T with diffusion tensor imaging (DTIs) in day 1, 3 and 7 post H-I insult. The apparent diffusion coefficient (ADC), fractional anisotropy (FA) and directional diffusivities (¦Ë// and ¦Ë¡Í) values were measured in white matter (WM) and gray matter (GM) lesion and their contralateral side. In day 1, the ADC, FA and ¦Ë// values showed significant decrease in GM lesion whilst WM lesion only showed a significant ADC increase. In day 3, the significant FA decrease and ¦Ë¡Í increase were found in GM lesion. Significant ADC and ¦Ë¡Í increase, and FA decrease were observed in the ipsilateral WM. By day 7, all DTI values were not statistically different between two hemispheres. Thus DTI is a sensitive method to study the early transient GM and WM changes after mild H-I insult by probing the microstructural changes.