Anoxic Brain Injury Detection with the Normalized Diffusion to ASL Perfusion Ratio: Implications for Blood-Brain Barrier Injury and Permeability

Twelve-point ROI linear regression analysis using DWI and ASL sequences. A, R²-versus-slope scatterplot for patients with anoxic brain injuries identified 30 of 35 cases positive for anoxic brain injury using a receiver operating characteristic analysis–determined cutoff of positive slopes and R² higher than 0.78. B, R²-versus-slope scatterplot for healthy controls excludes 28 of 34 cases negative for anoxic brain injury using the same slope and R² cutoffs.

Linear regression analysis demonstrates no significant linear dependence between slopes and interval to imaging (left) or between R² and interval to imaging (right), using DWI and the ASL sequences. Nonetheless, both exhibited positive trends. Linear fit equations: y = 0.01055 × x + 0.8847, P = .58 (left); y = 0.003945 × x + 0.8327, P = .38 (right).

Representative slices of voxelwise normalized NDP color map generation and corresponding DWI and ADC images. Anoxic brain injury (A and B) demonstrates homogeneous NDP ratios throughout the brain. B = 1000 DWI (C) and ADC (D) images show symmetric diffusion restriction in the frontal and parietal gray matter. E and F, A healthy control demonstrates heterogeneous NDP ratios throughout the brain. The heterogeneity is most pronounced in the white matter. B = 1000 DWI (G) and ADC map (H) show no diffusion restriction. Unilateral anoxic brain injury with NDP (I and J) showing 1 predominately homogeneous (anoxic) right hemisphere and 1 heterogeneous (nonaffected) left hemisphere. J, The asymmetry is most pronounced at the vertex. B = 1000 DWI (K) and ADC map (L) demonstrate unilateral cortical diffusion restriction in the right anoxic hemisphere, corresponding to the more homogeneous NDP ratios.