Brain MR imaging and spectroscopy for outcome prognostication after pediatric cardiac arrest

Children surviving cardiac arrest are at high risk of neurological morbidity and mortality; however, there is a lack of validated prognostic biomarkers. We aimed to evaluate brain magnetic resonance imaging (MRI) and spectroscopy (MRS) as predictors of death and disability. Secondly, we evaluated whether MRI/S by randomized group.

This single center study analyzed clinically indicated brain MRI/S data from children enrolled in a randomized controlled trial of 24 vs. 72 h of hypothermia following cardiac arrest. Two pediatric radiologists scored conventional MRIs. Lactate and N-acetyl-aspartate (NAA) concentrations (mmol/kg) were determined from spectra acquired from the basal ganglia, thalamus, parietal white matter and parietooccipital gray matter. Mortality and neurological outcomes (favorable = Pediatric Cerebral Performance Category [PCPC] 1, 2, 3 or increase < 2) were assessed at hospital discharge. Non-parametric tests were used to test for associations between MRI/S biomarkers and outcome and randomized group.

23 children with (median [interquartile range]) age of 1.5 (0.3-4.0) years. Ten (44%) had favorable outcome. There were more T2 brain lesions in the lentiform nuclei in children with unfavorable 12 (92%) vs. favorable 3 (33%) outcome, p = 0.007. Increased lactate and decreased NAA concentrations in the parietooccipital gray matter and decreased NAA in the parietal white matter were associated with unfavorable outcome (p's < 0.05). There were no differences for any biomarker by randomized group.

Regional cerebral and metabolic MRI/S biomarkers are predictive of neurological outcomes at hospital discharge in pediatric cardiac arrest and should undergo validation testing in a large sample.