Computed tomographic perfusion to Predict Response to Recanalization in ischemic stroke
Whereas most studies have demonstrated a gradual decrease in the effectiveness of endovascular therapy with longer onset‐to‐treatment times,7 our group has shown that good outcome rates in reperfused patients who meet magnetic resonance imaging (MRI) diffusion–perfusion mismatch criteria remain relatively constant over time.10 These findings suggest that patient selection criteria will play a key role in determining the outcome of endovascular thrombectomy trials in the extended time window.
A main drawback of MRI‐based patient selection is the small percentage of hospitals that have magnetic resonance (MR) readily available for the assessment of acute stroke patients. Therefore, the time it takes to obtain an MRI scan to triage acute stroke patients is unacceptably long in most hospitals. Another drawback of MRI is the relatively large percentage of patients who have contraindications to MRI because of metal implants (eg, pacemakers) or claustrophobia. To overcome the limitations of MRI‐based patient selection, computed tomographic (CT) perfusion imaging can be used instead. CT is much more widely available and has fewer contraindications than MRI. It is, however, not known whether CT perfusion‐based patient selection is comparable to MRI. Before embarking on a randomized trial with image‐based patient selection, we therefore conducted the CT Perfusion to Predict Response to Recanalization in Ischemic Stroke Project (CRISP) study to examine the utility of CT perfusion in identifying patients who are likely to benefit from endovascular therapy.