Can Apparent Diffusion Coefficient Values Predict Time of Onset in Term Neonates with Hypoxic–Ischemic Injury?

Abstract

Background Hypoxic–ischemic injury (HII) is a significant cause of neonatal morbidity and mortality. It had been postulated that apparent diffusion coefficient (ADC) abnormalities in term neonatal HII generally peak at 3 to 5 days after birth and subsequently “pseudonormalize” by the end of the first week. Thus, ADC values may provide a clue for timing of HII. Objective In this study, we sought to assess whether ADC values can always predict time of hypoxic ischemic insult. Methodology We prospectively analyzed 34 full-term neonates with suspected HII by diffusion-weighted (DW) magnetic resonance imaging (MRI) within 14 days after birth. DW images (DWIs) were assessed for areas of restricted diffusion at different locations that could be encountered in HII. ADC maps were generated and ADC values were calculated. Spearman correlation coefficient and receiver operating characteristic (ROC) curve analyses were performed. Results The mean age of neonates at time of MRI was 8 (±4) days (range: 2–14 days). No significant correlation detected between ADC values and age of neonates at time of imaging (p = 0.183; R2 = 0.06). ROC curve analysis showed that ADC values could not discriminate between neonates who were imaged early (≤7 days) or later (p = 0.391; area under the curve = 0.633). Conclusion ADC values may not be capable to accurately predict time of onset in term neonates with HII. ADC values should always be interpreted in combination with both conventional and DWIs, and each case should be individualized instead of generalization.