Hypoperfusion and vasoreactivity in the thalamus and cerebellum after stroke.

BACKGROUND AND PURPOSE Cerebellar hypoperfusion in the contralateral hemisphere after stroke is well studied and termed crossed cerebellar diaschisis. However, studies of hypoperfusion in the ipsilateral thalamus have been few. The purpose of this study was to investigate the prevalence of hypoperfusion and vasoreactivity to acetazolamide in the thalamus and cerebellum after stroke. METHODS We studied cerebral blood perfusion in the thalamus and cerebellum of 14 patients with unilateral cerebral infarction using [123I]isopropyliodoamphetamine single-photon emission computed tomography (123I-IMP SPECT). We also administered acetazolamide-stressed 123I-IMP SPECT to determine vasodilator capacity in these two areas. Regions of interest were drawn over the bilateral thalami and bilateral cerebellar cortices, and asymmetry indexes were obtained. RESULTS We found ipsilateral thalamic hypoperfusion in 12 (85.7%) and contralateral cerebellar hypoperfusion in 11 (78.6%) of 14 patients. Hypoperfusion was improved (p < 0.01 by the Wilcoxon signed rank test) in 11 (91.7%) of the 12 patients with ipsilateral thalamic hypoperfusion and in seven (63.6%) of the 11 patients with contralateral cerebellar hypoperfusion. CONCLUSIONS Hypoperfusion in the ipsilateral thalamus and contralateral cerebellum is common, and vasoreactivity to acetazolamide is preserved in both the thalamus and the cerebellum with hypoperfusion.