MR Imaging and Outcome of Term Neonates with Perinatal Asphyxia: Value of Diffusion-weighted MR Imaging and H MR Spectroscopy

Abstract

To compare the association between neurodevelopmental outcome in neonates with hypoxic-ischemic encephalopathy following perinatal asphyxia and (a) apparent diffusion coefficients (ADCs) in the thalamus and basal ganglia at diffusion-weighted (DW) magnetic resonance (MR) imaging and (b) hydrogen 1 (¹H) MR spectroscopic measurements in the basal ganglia. This retrospective study was approved by the local ethics committee, and the requirement to obtain informed consent was waived. Eighty-one term neonates with perinatal asphyxia underwent conventional and DW cranial MR imaging (median age, 4 days; age range, 1-14 days); 51 neonates also underwent ¹H MR spectroscopy. Neurodevelopment was assessed from 18 to 46 months. Patients with favorable and adverse outcomes were compared. Receiver operating characteristics analysis was performed in all patients, and uni- and multivariate logistic regression analyses were performed in 44 patients examined within 7 days of birth by using MR imaging scores, ADCs in the basal ganglia and thalamus, and ¹H MR spectroscopic measurements in the basal ganglia. An adverse outcome was seen in 28 of all 81 neonates (20 died, seven developed cerebral palsy, and one had severe mental retardation) and 22 of the 44 neonates examined within 7 days of birth with both ADC and ¹H MR spectroscopy. Poor outcome was associated with (a) lower ADCs in the basal ganglia (P < .001) and thalamus (P = .001) of neonates examined within 7 days of birth and (b) a higher lactate (Lac)-N-acetylaspartate (NAA) ratio in the basal ganglia (P < .001). Multivariate analysis showed that MR imaging score combined with Lac/NAA ratios or ADCs in the basal ganglia within the 1st week of life had a better association with outcome than did MR imaging alone (P = .006, area under the receiver operating characteristic curve [AUC] = 0.85 with Lac/NAA ratio; P < .0001, AUC = 0.93 with ADCs in basal ganglia). The combination of MR imaging score with ADCs or Lac/NAA ratios in the basal ganglia has a better association with outcome of asphyxiated term neonates than does MR imaging alone.