Acute Stroke Imaging Research Roadmap III Imaging Selection and Outcomes in Acute Stroke Reperfusion Clinical Trials

Abstract

Background and Purpose The STroke Imaging Research (STIR) group, the Imaging Working Group of StrokeNet, the American Society of Neuroradiology and the Foundation of the American Society of Neuroradiology sponsored an imaging session and workshop during the Stroke Treatment Academy Industry Roundtable (STAIR) IX on October 5–6, 2015 in Washington, D.C. The purpose of this roadmap was to focus on the role of imaging in future research and clinical trials. Methods This forum brought together stroke neurologists, neuroradiologists, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), industry representatives, and members of the U.S. Food and Drug Administration (FDA) to discuss stroke imaging research priorities in the light of an unprecedented series of positive acute stroke endovascular therapy clinical trials. Results The imaging session summarized and compared the imaging components of the recent positive endovascular trials, and proposed opportunities for pooled analyses. The imaging workshop developed consensus recommendations for optimal imaging methods for the acquisition and analysis of core, mismatch and collaterals across multiple modalities, and also a standardized approach for measuring the final infarct volume in prospective clinical trials. Conclusions Recent positive acute stroke endovascular clinical trials have demonstrated the added value of neurovascular imaging. The optimal imaging profile for endovascular treatment includes large vessel occlusion, smaller core, good collaterals and large penumbra. However, equivalent definitions for the imaging profile parameters across modalities are needed, and a standardization effort is warranted, potentially leveraging the pooled data resulting from the recent positive endovascular trials.

Real-world stent retriever thrombectomy for acute ischemic stroke beyond 6 hours of onset: analysis of the NASA and TRACK registries

“…Embolization into new territory was defined as treatment-related embolization into areas outside the target downstream territory 88. Intracranial hemorrhage (ICH) was classified as symptomatic (sICH) if it was associated with worsening of National Institutes of Health Stroke Scale score by ≥4 points within 24 hours.…”

Prehospital Scales for Large Vessel Occlusion

“…16 The latter includes good collaterals, small ischemic core, and important mismatch, factors that may be predicted on clinical grounds in the prehospital phase. The treatment response of favorable TRAIT profile patients is likely to be time independent.…”

Prevalence of Imaging Biomarkers to Guide the Planning of Acute Stroke Reperfusion Trials

“…One major difference between these positive trials and the previous negative ones (such as IMS III-Interventional Management of Stroke III trial) 7 is the use of imaging biomarkers to select patients for randomization; the imaging biomarkers used for each trial varied from trial to trial (Table I in the online-only Data Supplement). 8 In upcoming trials, both clinical variables, such as age and National Institutes of Health Stroke Scale (NIHSS) score, and imaging biomarkers will likely be used to identify patient cohorts and determine the feasibility of these trials. To compute accurate feasibility estimates of sample size, number needed to screen, and power, it is crucial to know the prevalence of both the clinical variables and imaging biomarkers in each of the time windows after symptom onset.…”