The prognostic impact of arterial spin labeling hyperperfusion in acute ischemic stroke: a systematic review and meta-analysis.

Hyperperfusion is related to vessel recanalization, tissue reperfusion, and collateral circulation. To determine the prognostic impact of hyperperfusion after an acute ischemic stroke (AIS) identified by arterial spin labeling (ASL) cerebral blood flow. Studies published in PubMed, Embase, and Cochrane Library databases were searched. Studies assessing the diagnostic performance of ASL hyperperfusion after AIS were included. Functional prognosis, hemorrhagic transformation (HT), infarction volume, and penumbra salvage volume were evaluated. The standardized mean difference or risk ratio was pooled, implementing a random effect model. Multiple subgroup analyses were performed. Seven studies including 617 participants were included in this meta-analysis. ASL hyperperfusion in AIS was correlated well with symptom severity and outcome after 24 h National Institutes of Health Stroke Scale (NIHSS) and 90-day modified Rankin Scale (mRS). Earlier ASL hyperperfusion was associated with a smaller infarction volume and a larger penumbra salvage volume, while also indicating a higher risk of HT. In addition, in subgroup analysis, our results demonstrated that thrombolysis, mechanical thrombectomy treatment, early improvement of NIHSS, and involving infarction in cortical territory are associated with ASL hyperperfusion. ASL hyperperfusion was related to a favorable functional outcome but an increased risk of HT. Stroke patients with hyperperfusion showed smaller infarction volume and larger penumbra salvage volume than those with non-hyperperfusion.