Table 1

Methods of measurement of cerebral blood flow

TechnologySpecific methodsImportant points
CBF, cerebral blood flow; CT, computed tomography; IMP, inosine 5′-monophosphate; MR, magnetic resonance; SPECT, single photon emission computed tomography; 99mTcHMPAO, technetium-99m hexamethylpropylene amine oxime.
Perfusion (regional CBF)
Positron emission tomography15O labelled waterAllows oxygen consumption measurement
Quantitative
Xenon based techniquesStable xenon methodsPotentially quantitative
Intravenous xenon methods
Xenon SPECT
Xenon CT
MR based techniquesExogenous perfusionUsing gadolinium bolus
Endogenous perfusionNon-invasive
CT based techniquesContrast perfusion imaging
Xenon CT
SPECT99mTcHMPAOSemiquantitative
123I labelled IMP
Transcranial Duplex ultrasoundUltrasound perfusionQuantification not yet possible
Volume flow (in major arteries)
Carotid and vertebral ultrasoundDoppler based techniquesFlow in major arteries and not tissue perfusion
Non-Doppler based techniques
Transcranial Doppler ultrasoundVelocity rather than flow measurement