MR imaging and outcome of term neonates with perinatal asphyxia: value of diffusion-weighted MR imaging and ¹H MR spectroscopy

Abstract

Purpose: 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.

Materials and methods: 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.

Results: 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).

Conclusion: 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.