Figure 5.

Evidence of cerebral ischaemia and hyperglycolysis. CT, CBF, CMRO₂, OEF, and ¹⁸F-FDG kinetic parameters obtained in a 40-year-old female within 24 h of severe TBI resulting from a fall. Imaging was obtained following evacuation of a subdural haematoma. Plasma glucose during PET was 3.7 mmol/l. (A) CT demonstrates residual subdural blood with minimal midline shift and underlying haemorrhagic contusions. Regions of interest are defined for haemorrhagic lesion (core, red), hypodense tissue (penumbra, blue), and a 1 cm border zone of normal-appearing tissue (peri-penumbra, green). (B) Co-registered parametric maps of CBF, CMRO₂, OEF, K₁, K_i and k₃. The regions with a critical increase in OEF above the individually calculated threshold (ischaemic brain volume) and increased phosphorylation activity (k₃ ‘hotspot’) are both shown in red overlying the CT scan. The ischaemic brain volume and k₃ hotspot volume were 96 ml and 174 ml, respectively, and the volume of overlap between these two tissue classes in this patient was 38 ml.