Diffusion-weighted and conventional MR imaging in neonatal hypoxic ischemia: two-year follow-up study.

PURPOSE: To establish the supplemental value of diffusion-weighted (DW) magnetic resonance (MR) imaging beyond conventional MR to predict clinical outcome after neonatal hypoxic ischemia (HI) at 2 years of age.
MATERIALS AND METHODS: Forty-six infants with neonatal HI were enrolled in this prospective study, after approval by the local ethical committee and informed consent of the parents. Neonatal MR imaging ranged from 1 to 45 days after birth. Apparent diffusion coefficient (ADC) was measured in 14 brain regions. DW and conventional images were qualitatively scored for abnormalities, resulting in cumulative scores and patterns of damage. Surviving infants were scored for motor outcome at the age of 2 years, and outcome was classified as poor if the motor score was less than 70 or in case of death. Analyses were performed for the whole group, with additional analyses for the early (0-4 days after birth) and late (>4 days after birth) imaging groups.
RESULTS: Twenty-five infants had a good outcome and 21 had a poor outcome. Only in the early imaging group, the infants with poor outcome had significantly lowered ADC values in several brain areas, with the posterior limb of the internal capsule being the most predictive (Wald score = 5.7; P = .017). Cumulative scores of DW imaging were the best predictor of poor motor outcome at the age of 2 years (Wald score = 7.2, P < .01). The basal ganglia and central cortex and the diffuse pattern of brain damage were highly associated with poor outcome (Fisher exact test = 29.8; P < .001).
CONCLUSION: In neonatal HI, DW imaging is a useful additional MR technique to predict the motor outcome at 2 years. Local ADC values had a limited value. Recognition of the patterns of brain damage with DW and conventional MR imaging can be used as a diagnostic tool in neonatal HI. (c) RSNA, 2008.