Delineating the Boundary between the Ischemic Penumbra and Regions of Oligaemia Using pH-weighted MRI (pHWI)
Zhou J, Huang J, van Zijl P, Sun W, Sun P
Johns Hopkins University, Kennedy Krieger Institute
Permanent middle cerebral artery occlusion was studied to test whether pH-weighted imaging (pHWI) can subdivide PWI-DWI mismatch into regions of benign oligaemia and a true penumbra (viable area with impaired metabolism). Regions of pH-deficit were always larger than or equal to regions of cellular depolarization (DWI-deficit) and smaller than or equal to PWI-deficits. Group analysis showed that pHWI-deficits at 3.5 hr predicted well resulting infarct at 24 hr endpoint. Final infarcts were smaller than PWI-deficits (65-90%, depending on occlusion severity) and, in most cases, much larger than initial DWI-deficits. These data support that pHWI can separate penumbra and benign oligaemia.