Fig 1. A map of microvascular PS acquired from first-pass dynamic contrast-enhanced images over 60 seconds. There was a region of PS elevation encompassing the right insula cortex and portions of the right frontal and temporal lobes. CBF, CBV, and TTP maps showed hypoperfusion in these regions (not shown) in this 86-year-old woman with an acute right MCA stroke. Four 10-mm circular regions of interest were placed over the region of PS elevation, as depicted here, to acquire 4 PS measurements that were then averaged to give a single value for statistical analysis (PS_infarct). Mirror regions of interest were automatically placed on the contralateral, nonischemic, homologous hemisphere to provide a control value (PS_control). Note that the PS values calculated by the application are scaled to 0.5 mL/100 mL per minute. No HT was found on follow-up imaging.