"gray matter"
"Most CT perfusion protocols are centred upon the basal ganglia and supra-ganglionic level. This excludes a large volume of the brain, e.g. the posterior fossa and superior cerebral hemispheres."
Expected headings
"Summary"
"Perfusion scotoma is a recognised pitfall of CT perfusion imaging in acute ischaemic stroke from large vessel occlusion, characterised by systematic underestimation of the ischaemic core in the delayed time window (typically beyond six hours from symptom onset). Perfusion scotoma results from failure of automated software to detect already-infarcted tissue, yielding falsely favourable perfusion maps. The underestimated volume corresponds to the difference between the actual infarct volume on follow-up imaging and the CTP-derived core estimate. This phenomenon occurs in approximately 25% of patients undergoing endovascular thrombectomy, with independent predictors including male sex, lower ASPECTS at admission, more distal vessel occlusion, and longer onset-to-CT time, with an optimal discriminatory cutoff of seven hours 9,10."
"Significant cervical internal carotid artery stenosis can increase MTT in its vascular territory, mimicking ischaemia and leading to overestimation of penumbra and underestimation of infarct core; concurrent neck CT angiography at the time of CTP helps avoiding this pitfall 12."