Evaluation of corpus callosum Anisotropy in young adults with fetal alcohol syndrome according to diffusion tensor imaging

Background: Fetal alcohol syndrome (FAS) and associated disorders resulting from maternal alcohol use during gestation are among the most common developmental disorders. However, they are rarely diagnosed and not fully understood in terms of their behavioral and neurocognitive phenotype. Prenatal exposure leads to alterations in facial morphology, growth, and neurocognition. The nature and extent of teratogenic effects on the brain and the relationship between such effects and observed behaviors remain in debate because there are no established markers for the neurological effects of exposure. In this study, we examined the impact of prenatal alcohol exposure on white-matter integrity in the corpus callosum by using diffusion tensor imaging (DTI) and herein describe the relationship between such effects and observed physical and behavioral outcomes. Methods: DTI was used to evaluate diffusion anisotropy in the genu and splenium of corpus callosum in 16 low-income, primarily African-American volunteers. Volunteers were recruited from a cohort of young adults who had received neuropsychological evaluations during adolescence. Nine had been prenatally exposed to alcohol and had characteristics of FAS, and seven were nonexposed controls. Results: Significant difference in the means for diffusion fractional anisotropy (t = 2.26, df = 9, p < 0.002) and apparent diffusion coefficient (t = 2.14, df = 14, p < 0.008) were observed in the corpus callosum of alcohol-exposed youth compared with nonexposed youth. No significant differences were found in intracranial volume between these groups. Conclusions: Our results illustrate that DTI can be used in evaluating the integrity of corpus callosurn in alcohol-exposed individuals. If future studies support these findings, diffusion anisotropy, represented by fractional anisotropy, has the potential to be used as a clinical marker in the diagnosis of FAS.