MR Imaging of hypoxic ischemic encephalopathy – Distribution Patterns and ADC value correlations

BACKGROUND AND PURPOSE: Neonatal hypoxic-ischemic encephalopathy causes hypoxic brain injury. Due to differences in brain maturity at time of insult, severity of hypotension and duration of insult, there are four distinct patterns of brain injury. Magnetic resonance imaging is the most sensitive modality for evaluating these patterns of brain injury. Additional role of Diffusion weighted imaging and ADC values can be useful in the evaluation of such cases. We conducted this study to analyse the usefulness of ADC values in the brain tissue affected by hypoxic-ischemic injury. MATERIALS AND METHODS: We conducted a prospective study of all the patients referred to our department for magnetic resonance scanning of brain with history of hypoxic ischemic encephalopathy and clinical features cerebral palsy. 23 Cases with imaging manifestations of hypoxic ischemic encephalopathy were included in the study. We studied distribution patterns of HIE in our cases and calculated the ADC values of involved as well as normal grey and white matter. Further, sensitivity, specificity, predictive values, and likelihood ratios for each dichotomized diffusion and ADC values were obtained Wilson Score method. RESULTS: The most common distribution pattern in our study was involvement of peri-rolandic area (15 cases, 65%). ADC values were significantly (p < 0.005) increased in abnormal white matter. No significant changes (p = 0.8) were seen in ADC values of normal and abnormal grey matter. CONCLUSIONS: Due to significant increase in ADC values of affected white matter, ADC value can be used as a marker to detect chronic sequel of hypoxic ischaemic brain injury. Another observation was the perirolandic brain tissue being most common area of involvement in the cases with cerebral palsy.