Table 2.

Total cerebral blood flow.

Reference	Aim of study	Type of study	n MCI	n AD	n VD	n Controls	Parameters	Outcome
Albayrak et al. (2006)	Comparison of cerebral blood flow in demented (AD, VD) and cognitively normal subjects, both with brain atrophy	Cross-sectional		9	9	10	Flow velocities and cross-sectional area of the vessel in ICAs and VAs	Total, anterior and right CBF lower in dementia, no difference between two types of dementia
Doepp et al. (2006)	Possible differentiation of AD and VD by various extra- and intracranial ultrasound parameters	Cross-sectional		20	20	12	Flow velocities and PI in MCAs, flow velocities and cross-sectional area in ICAs and VAs, cerebral circulation time, global cerebral blood volume	No significant difference in trans- and extracranial ultrasound between AD and VD
Gusti et al. (2004)	Comparison of carotid flow velocities and flow curve in AD and controls	Cross-sectional		18		40	Flow velocities in carotid arteries	Lower cerebral vascular filling in AD
Maalikjy Akkawi et al. (2003)	Possibility of CBF volume assessment by TCD, difference between AD and controls, correlation with cognitive decline	Cross-sectional		50		50	Flow velocities and vessel diameter in ICA and VA, calculation of cerebral blood flow	Decrease in CBF volume in AD compared to controls, positive correlation between dementia severity and CBF
Schreiber et al. (2005)	CBF, cerebral circulation time and cerebral blood volume in AD, VD and controls	Cross-sectional		20	20	12	Flow velocity and cross-sectional area of ICA and VA, time of contrast agent transfer from ICA to IJV	Difference in CBF and transit time between dementia and controls, no difference in CBF volume or between AD and VD

AD, Alzheimer’s disease; CBF, cerebral blood flow; ICA, internal carotid artery; IJV, internal jugular vein; MCA, middle cerebral artery; MCI, mild cognitive impairment; PI, pulsatility index; TCD, transcranial Doppler; VA, vertebral artery; VD, vascular dementia.