Fig. 4: Comparison to microdialysis data showing a drastic reduction in perfusion once cerebral ischemia occurs.

a Trends of lactate-to-pyruvate ratio (L/P) with increasing ICP for the current experiment (circles) and previously reported results (cross⁴⁹). The dashed line at L/P = 30 has been suggested as a threshold for cerebral ischemia⁴⁸. b Trends of L/P vs. the nondimensionalized cumulative cortical micro-perfusion parameter \({{\rho }}({{{{{\rm{CMC}}}}}}_{{{{{{\rm{cort}}}}}}})^{2}/{{{{{\rm{PP}}}}}}\). c Trends of \({{\rho }}({{{{{\rm{CMC}}}}}}_{{{{{{\rm{cort}}}}}}})^{2}/{{{{{\rm{PP}}}}}}\) with \({{{{{\rm{ICP}}}}}}/{{{{{\rm{MAP}}}}}}\) in logarithmic scales. In (a–c), the same group of encircled cases are identified to have cerebral ischemia and significantly low nondimensionalized perfusion, all occurring at \({{{{{\rm{ICP}}}}}}/{{{{{\rm{MAP}}}}}}\ge 0.5\). d Variations of \({{{{\rho }}{{{{{\rm{V}}}}}}}_{5}}^{2}/{{{{{\rm{PP}}}}}}\) with \({{{{{\rm{ICP}}}}}}/{{{{{\rm{MAP}}}}}}\). For (a–d), the colored markers show the original data; the hollow ones are validation data. Cases whose microdialysis data are not available are not plotted. For (c, d), cases whose L/P are larger than 30 are marked by triangles. e, f A sample comparison of the perfusion heatmaps for the baseline (e) and ischemia (f) cases for piglet #0306 showing the omnipresent sharp reduction in perfusion during ischemia. Source data for (a–d) are provided as a Source Data file.