Posterior reversible encephalopathy syndrome (PRES) and CT perfusion changes

Table 3 CT perfusion changes in various brain insults

Etiology	CBF	CBV	MTT	TTP
Infarct core	↓	↓	↑	↑
Ischemic penumbra	Varies; usually↓	↑	Varies; usually ↑	↑
seizure	↑	↑	↓	↓
PRES*	Usually ↑ but can be ↓	↑ or ↓	Equivocal	↓

CBF = cerebral blood flow; CBV = cerebral blood volume; MTT = mean transit time; TTP = time to peak.
*= CTP changes in PRES depend on whether it is a hyperperfusion or hypoperfusion mechanism of PRES.

ISSN: 1865-1380