Objective    To investigate the disturbance of perfusion patterns attributable to cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (SAH) by perfusion-weighted magnetic resonance imaging (PWI) and digital subtraction angiography (DSA)

and to study the correlation between cerebral hemodynamics and CVS in SAH patients.     Methods     PWI and DSA were performed on 38 SAH patients about 7±2 d after SAH. The patients were divided into a non-CVS group

a mild CVS group

a moderate CVS group

and a severe CVS group according to the CVS degrees. Parameters including relative cerebral blood flow (rCBF)

relative cerebral blood volume (rCBV)

mean transit time (MTT)

time to peak (TTP) in regions of interest (ROIs) of the anterior cerebral artery (ACA) perfusion area

the middle cerebral artery (MCA) perfusion area

and the basal ganglia area of each hemisphere were analyzed based on PWI. The correlation between the parameters and CVS was studied.     Results    Twenty-eight cases with vasospasm in at least one blood vessel were found in the patients

including 10 cases in the non-CVS group

9 in the mild CVS group

10 in the moderate CVS group

and 9 in the severe CVS group. The parameters rCBF

rCBV

TTP and MTT were statistically analyzed by Spearman rank correlation coefficient. In all ROIs

rCBV and rCBF decreased as CVS worsened (P0.05). In the mild and moderate CVS groups

rCBF and rCBV decreased or increased in all ROIs. rCBF decreased significantly in the severe CVS group as compared with that in the control group (P0.05). MTT and TTP in the CVS groups had a significant tendency of linear increase. TTP was significantly delayed in the CVS groups as compared with that in the control group

and had significant rank correlation (r=0.489 to 0.730

P0.01).     Conclusion    PWI can provide quantitative information on the changes of cerebral hemodynamics. The combination of PWI and DSA has clinicopathologic significance when investigating the correlation between cerebral hemodynamics and CVS degrees in SAH patients.