A Critical Review of Alberta Stroke Program Early CT Score for Evaluation of Acute Stroke Imaging

Oh hell, instead of just predicting outcome tell us the outcome so you can fix the problems of those that don't have a good outcome.  Action, not talk.
http://journal.frontiersin.org/article/10.3389/fneur.2016.00245/full?

Julian Schröder* and Götz Thomalla

• Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Assessment of ischemic stroke lesions on computed tomography (CT) or MRI using the Alberta Stroke Program Early CT Score (ASPECTS) is widely used to guide acute stroke treatment. We aimed to review the current evidence on ASPECTS. Originally, the score was developed for standardized lesion assessment on non-contrast CT (NCCT). Early studies described ASPECTS as a predictor of functional outcome and symptomatic intracranial hemorrhage after iv-thrombolysis with a threshold of ≤7 suggested to identify patients at high risk. Following studies rather pointed toward a linear relationship between ASPECTS and functional outcome. ASPECTS has also been applied to assess perfusion CT and diffusion-weighted MRI (DWI). Cerebral blood volume ASPECTS proved to be the best predictor of outcome, outperforming NCCT-ASPECTS in some studies. For DWI-ASPECTS varying thresholds to identify patients at risk for poor outcome were reported. ASPECTS has been used for patient selection in three of the five groundbreaking trials proving efficacy of mechanical thrombectomy published in 2015. ASPECTS values predict functional outcome after thrombectomy. Moreover, treatment effect of thrombectomy appears to depend on ASPECTS values being smaller or not present in low ASPECTS, while patients with ASPECTS 5–10 do clearly benefit from mechanical thrombectomy. However, as patients with low ASPECTS values were excluded from recent trials data on this subgroup is limited. There are several limitations to ASPECTS addressed in a growing number of studies. The score is limited to the anterior circulation, the template is unequally weighed and correlation with lesion volume depends on lesion location. Overall ASPECTS is a useful and easily applicable tool for assessment of prognosis in acute stroke treatment and to help guide acute treatment decisions regardless whether MRI or CT is used. Patients with low ASPECTS values are unlikely to achieve good outcome. However, methodological constraints of ASPECTS have to be considered, and based on present data, a clear cutoff value to define “low ASPECTS values” cannot be given.

Introduction

The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is widely used in clinical practice to assess the extent of early ischemic changes on brain imaging for acute stroke treatment. ASPECTS has been applied to various imaging modalities in acute stroke imaging since its introduction in 2000. ASPECTS is a 10-point scoring system with anatomical regions distributed over the MCA territory (1).

It was designed as a robust imaging measure to predict outcome in intravenous thrombolysis. ASPECTS has drawn a lot of attention due to its use for patient exclusion in the 2015 trials demonstrating efficacy of mechanical thrombectomy (2–4).

Due to high efficacy, we will see an increase of mechanical thrombectomy over the course of the next years and with it probably an increasing use of ASPECTS in routine clinical practice, as patient stratification is key in this time-dependent treatment. There are also a rapidly growing number of scientific studies using ASPECTS in stroke research or addressing methodological questions concerning ASPECTS (please see Figure 1 for an overview of the number of studies published per year over the last 10 years). This article aims to summarize the current evidence on ASPECTS in a topical and selective review and to explain its applications in clinical practice and trials.