Emergency Radiology

, Volume 26, Issue 3, pp 319–329 | Cite as

An acute stroke CT imaging algorithm incorporating automated perfusion analysis

  • Danielle ByrneEmail author
  • John P. Walsh
  • Peter J. MacMahon
Review Article


In this paper, we propose a CT imaging algorithm for patients presenting with suspected acute stroke that incorporates automated CT perfusion (CTP) imaging. The algorithm details evaluation of the non-contrast CT (NCCT) for hemorrhage and acute ischemia, calculation of ASPECTS, with performance and interpretation of CTP if appropriate. In particular, we consider the key steps in expeditious interpretation of non-contrast CT and CT angiography in the context of suspected acute ischemic stroke. Given the recent expansion of the “imaging based” treatment window for thrombectomy from 6 to 24 h in the 2018 American Heart Association stroke guidelines, we consider the key criteria in the decision to perform CT perfusion and the patient cohorts in which this might be most helpful. We also describe how imaging findings might be incorporated into the treatment paradigm for suspected with acute ischemic stroke and we allude to some of the most frequently encountered pitfalls associated with CTP which we think will be particularly helpful for radiologists and stroke physicians who are considering adding CT perfusion to their work-up for acute stroke.


Computed tomography, X-ray Perfusion Stroke Brain ischemia Computed tomography angiography 



2nd segment of the anterior cerebral artery


Anterior cerebral artery


Arterial input function


Acute ischemic stroke


Alberta Stroke Program Early CT Score


Cerebral blood flow


Cerebral blood volume


Computed tomography


Computed tomography angiography


Computed tomography perfusion


Digital subtraction angiography


Diffusion-weighted imaging


Emergency Department


Intracranial carotid artery




M1 segment of the middle cerebral artery


Middle cerebral artery


Magnetic resonance imaging


Mean transit time


Posterior cerebral artery


Non-contrast-computed tomography


RApid processing of PerfusIon and Diffusion


relative cerebral blood flow


relative cerebral blood volume


Venous outflow function


multiphase CTA


single phase CTA


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© American Society of Emergency Radiology 2019

Authors and Affiliations

  1. 1.Department of RadiologyMater Misericordiae University HospitalDublin 7Ireland
  2. 2.School of MedicineUniversity College DublinDublinIreland

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