Objective  To observe the changes in cerebral microcirculation after subarachnoid hemorrhage (SAH) and to study its correlation with cerebral vasospasm (CVS).   Methods  Eighty-five SAH patients and 35 controls

enrolled in this study as perspective study subjects

were divided into SAH group and control group

CVS group and non-CVS group (nCVS)

symptomatic CVS (sCVS) group and asymptomatic CVS (asCVS) group. All the subjects underwent CT perfusion (CTP) and the associated parameters

including cerebral blood flow (CBF)

cerebral blood volume (CBV) and mean transit time (MTT)

were recorded for final analysis.   Results  Compared to the control group

the CBF and MTT were significantly changed in SAH group (P＜0.05). The CBF was lower while the MTT time was longer in SAH group than in control group. The CBF was lower in CVS

sCVS and Hunt-Hess Ⅲ to Ⅴ groups than in  nCVS

asCVS and Hunt-HessⅠ to Ⅱgroups (P0.05). Delayed ischemic neurological dysfunction (DIND) was found in 7 patients with a MTT time of 6.31 to 12.72 s

hemiplegia occurred in 2 of the patients

and 1 patient died.   Conclusion  Changes in microcirculation hemodynamics after SAH are correlated with CVS and can be detected during CTP.