Neurology: Quantitative diffusion-weighted magnetic resonance neuroimaging in relation to cardiac arrest outcomes in children

Magnetic resonance diffusion magnetic resonance imaging (MRI) can quantify the extent of
hypoxic-ischemic brain injury after cardiac arrest.
Because ADCs decline exponentially with age, a study published in Neurology established an association of 1) having > 10% of brain tissue below the new age-dependent ADC threshold, and 2) whole-brain mean ADCs and adverse outcomes
.
The goal of the study was to determine the association
between an adult-derived apparent diffusion coefficient (ADC) < an adult-derived threshold of 650x10-6mm2/s and adverse outcomes following pediatric cardiac arrest in > 10% of brain tissue.

A retrospective study of cardiac arrest patients under 18 years of age and clinically obtained brain MRI within
7 days.
The primary outcome was adverse neurological status at hospital discharge based on the child's Brain Performance Category (PCPC) score.

Extract ADC images
from three-way diffusion imaging.
Determine if each patient has > 10% voxels with ADCs below a pre-set threshold
.
The brain-wide average ADC
for each patient was calculated.

The quantitative diffusion threshold of MRI within 7 days of cardiac arrest is associated
with poor prognosis in children.
Age-independent ADC thresholds are highly specific
for predicting poor outcomes.
However, specificity and sensitivity increase
when age-dependent ADC thresholds are used.
Age-dependent ADC thresholds can improve prognostic accuracy and require further investigation
in larger cohorts.

This study provides Category III evidence that quantitative diffusion-weighted imaging (DWI) obtained within 7 days can predict adverse outcomes
in children.

Source: Kirschen MP, Berman JI, Liu H, et al.
Association Between Quantitative Diffusion Weighted Magnetic Resonance Neuroimaging and Outcome After Pediatric Cardiac Arrest [published online].
ahead of print, 2022 Aug 26].
Neurology.
2022; 10.
1212/WNL.
0000000000201189.
doi:10.
1212/WNL.
0000000000201189