The Source for Neurovascular News and Education

February 27, 2024


Key Points:

  • Meta-analysis focuses on role of perfusion imaging treatment of acute ischemic stroke
  • Perfusion imaging linked to better outcomes in some cases, provides useful prognostic information


Perfusion imaging likely guides therapy for acute ischemic stroke in such a way as to optimize outcomes, according to a meta-analysis published online November 9, 2016, ahead of print in the Journal of NeuroInterventional Surgery. The authors warn, however, that several questions about its benefits and drawbacks still remain unanswered.

In their systematic review of the literature, Steven W. Hetts, MD, UCSF School of Medicine (San Francisco, CA), and colleagues identified 2 randomized controlled trials, 10 cohort studies, and 1 case-control study published between 2011 and 2016 that examined the utility of perfusion imaging for determining treatment eligibility among patients with acute ischemic stroke.

In a meta-analysis of the collected data from 8 of the identified studies, 994 patients treated with the aid of perfusion imaging were compared with 1,819 patients treated with standard care.

Improvement in Functional Outcome

Overall, there was a trend favoring a larger proportion of patients who received perfusion imaging having a good outcome at 3 months, compared with those who did not (51.1% vs 45.6%; P = .06). The summary estimate calculated through random effects modeling also suggested a trend favoring perfusion imaging-based treatment (OR 1.29, 95% CI 0.99-1.69, P = .06).

Several subgroup analyses of studies that took into consideration stroke onset time and use of multimodal therapy found that when onset time was accounted for, outcomes were more favorable with perfusion imaging. This same pattern was not seen in studies that included patients with unclear or unknown stroke onset times, however. Studies that included multimodal therapy (intravenous tPA and endovascular thrombectomy) showed the greatest benefit for perfusion imaging (table 1).

Table 1. Link Between Perfusion Imaging and Favorable Outcome


OR (95% CI)

P Value

Specified Stroke Onset

1.30 (1.08-1.57)

< .01

Unclear/Unknown Stroke Onset

1.08 (0.76-1.53)


Multimodal Therapy

1.89 (1.44-2.51)

< .01


Useful Prognostic Information

The authors also identified 36 studies that evaluated the utility of perfusion imaging for predicting patient outcomes. In all but one of the studies, physiological imaging characteristics, including perfusion status, ischemic core volume, and collateral flow, were predictors of outcome.

“While the findings of our systematic review provide additional support for multimodal imaging, the role of perfusion imaging in current clinical practice remains a topic of contention,” write the authors. Concerns include lack of standardized definitions, inconsistency in imaging technique, and potential delays in treatment.

They recommend that future efforts focus on improvements in characterization of perfusion imaging findings in study patient populations, so that outcome data can in turn be used to optimize and standardize study inclusion and exclusion criteria. This could one day inform care in the clinical setting, they suggest, noting that the role of multimodal imaging is being addressed in the ongoing DEFUSE 3 and DAWN trials.

The investigators conclude that their findings demonstrate “that perfusion imaging may allow better patient selection leading to a greater number of patients receiving reperfusion therapy with higher rates of successful functional outcomes. The ongoing generation of perfusion-based clinical trials will move us closer to a definitive answer.”



Ryu WHA, Avery MB, Dharampal N, et al. Utility of perfusion imaging in acute stroke treatment: A systematic review and meta-analysis. J NeuroInterv Surg. 2016;Epub ahead of print.



Dr. Hetts reports being a co-investigator in the DAWN and DEFUSE trials.