Table 3.

Effects of SVD on CVR.

Study	CVR in relation to SVD features	CVR in subjects vs. controls	CVR in relation to other features	Safety and tolerability
Gauthier et al.15 Total n = 85	WMH volume not associated with frontal lobe CVR	Frontal lobe CVR 0.22 ± 0.06%/mm Hg in subjects vs. 0.25 ± 0.08%/mm Hg in young controls	CVR decreased with age	2 patients excluded due to discomfort when breathing via Respiract™ device
Richiardi et al.16 Total n = 63	No association between ‘CVR velocity’ and Fazekas score	Mean time to reach 90% of peak BOLD response 59 s for MCI and AD patients vs. 33 s for controls	‘CVR velocity’ increased with increasing MMSE score	No discomfort reported
Conijn et al.17 Total n = 49	Microbleeds associated with decrease in CVR. No CVR association with lacunes or WMH severity	Not applicable	CVR decreased with increasing age, female gender and increasing diastolic blood pressure	Not assessed
Yezhuvath et al.18 Total n = 25	Decreased CVR associated with increased WMH volume	CVR decreased in frontal lobe, insula and anterior cingulate gyrus in subjects compared to controls	Decreased CVR associated with a lower Boston Naming Score	5 subjects and 4 controls declined to take part in CVR scan but no reasons given
Hund-Georgiadis et al.19 Total n = 17	Increased severity of SVD features (composite score of WMH, lacunes and enlarged perivascular spaces) associated with decreased CVR	Subjects had lower whole brain CVR than older controls, who in turn had lower CVR than young controls. Subjects had reduced CVR in frontal and parietal cortex vs. both control groups and in occipital cortex vs. young controls	CVR decreased with age	Not assessed

AD: Alzheimer’s disease, MCI: mild cognitive impairment, MMSE: Mini Mental State Examination.