The ratio of arterial spin labeled (ASL) perfusion to diffusion weighted imaging (DWI) is generally homogeneous in the anoxic/hypoxic injury population. Conversely, the ratio is more heterogeneous in the non-anoxic/hypoxic population. By plotting these ratios in a graphical format in the form of an axial color map of the brain—referred to as a normalized diffusion to perfusion (NDP) ratio colormap—it may be determined whether a patient has suffered from an anoxic/hypoxic injury. Thus, the anoxic and non-anoxic injury patients will have, respectively, homogenous and heterogeneous color maps. Anoxic brain injury patients have a global homogeneously positive relationship between qualitative ASL perfusion and diffusion weighted signal such that areas of restricted diffusion show significantly increased ASL perfusion signal, which may be attributable to BBB integrity. The NDP ratio colormap provides an imaging biomarker to differentiate anoxic brain injury from normal controls and to potentially assess BBB integrity.
IMAGING BIOMARKERS BASED ON RATIO BETWEEN DIFFUSION AND PERFUSION