OBJECTIVE We propose to investigate the fractional anisotropy (FA) values in pediatric patients with closed head trauma and correlate them with the initial Glasgow Coma Scale (GCS). METHODS A retrospective evaluation of 24 pediatric patients (15 men, 9 women; mean age, 13 years; range, 2-18 years) who underwent both unenhanced head computed tomography and cerebral magnetic resonance imaging (MRI), including the tensor diffusion sequence, within 30 days of the incident. Twenty-two atraumatic control patients (9 men, 13 women; mean age, 9 years; range, 4-17 years) were randomly selected from the records of the radiology department within the same period. Fractional anisotropy measurements were taken from each of 6 major white matter volumes. Data extracted from the record of each subject included GCS, initial head computed tomographic results, and length of hospital stay. Kruskal-Wallis and t tests were used for statistical evaluation. RESULTS The mean acute score on the GCS was 9.7 +/- 5. Mean duration of hospitalization days was 8.7 +/- 10. Statistically significant differences in mean FA values between trauma and control subjects were noted in corpus callosum. Trauma patients with positive findings on MRI and with GCS less than 10 also had lower FA values than patients with GCS greater than 10 and patients who had normal MRI findings. There was a negative correlation between time to discharge and FA values. CONCLUSIONS In pediatric head trauma, MRI diffusion FA measurements can show abnormalities despite normal-appearing brain MRI findings. Larger investigations are required to verify the stability of correlations.