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Assessment of computed tomography perfusion software in predicting spatial location and volume of infarct in acute ischemic stroke patients: a comparison of Sphere, Vitrea, and RAPID
  1. Ryan A Rava1,2,
  2. Kenneth V Snyder2,3,
  3. Maxim Mokin4,
  4. Muhammad Waqas2,3,
  5. Xiaoliang Zhang1,
  6. Alexander R Podgorsak1,2,5,
  7. Ariana B Allman1,2,
  8. Jillian Senko1,2,
  9. Mohammad Mahdi Shiraz Bhurwani1,2,
  10. Yiemeng Hoi6,
  11. Jason M Davies2,3,7,
  12. Elad I Levy2,3,
  13. Adnan H Siddiqui2,3,
  14. Ciprian N Ionita1,2,3,5
  1. 1Biomedical Engineering, University at Buffalo-The State University of New York, Buffalo, New York, USA
  2. 2Canon Stroke and Vascular Research Center, Buffalo, New York, USA
  3. 3Neurosurgery, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York, USA
  4. 4Neurosurgery, University of South Florida, Tampa, Florida, USA
  5. 5Medical Physics, University at Buffalo - The State University of New York, Buffalo, New York, USA
  6. 6Canon Medical Systems USA Inc, Tustin, California, USA
  7. 7Biomedical Informatics, University at Buffalo,The State University of New York, Buffalo, New York, USA
  1. Correspondence to Dr Ciprian N Ionita, Neurosurgery and Biomedical Engineering, Toshiba Stroke and Vascular Research Institute, University at Buffalo School of Engineering and Applied Sciences, Buffalo, NY 14206, USA; cnionita{at}


Background CT perfusion (CTP) infarct and penumbra estimations determine the eligibility of patients with acute ischemic stroke (AIS) for endovascular intervention. This study aimed to determine volumetric and spatial agreement of predicted RAPID, Vitrea, and Sphere CTP infarct with follow-up fluid attenuation inversion recovery (FLAIR) MRI infarct.

Methods 108 consecutive patients with AIS and large vessel occlusion were included in the study between April 2019 and January 2020 . Patients were divided into two groups: endovascular intervention (n=58) and conservative treatment (n=50). Intervention patients were treated with mechanical thrombectomy and achieved successful reperfusion (Thrombolysis in Cerebral Infarction 2b/2 c/3) while patients in the conservative treatment group did not receive mechanical thrombectomy or intravenous thrombolysis. Intervention and conservative treatment patients were included to assess infarct and penumbra estimations, respectively. It was assumed that in all patients treated conservatively, penumbra converted to infarct. CTP infarct and penumbra volumes were segmented from RAPID, Vitrea, and Sphere to assess volumetric and spatial agreement with follow-up FLAIR MRI.

Results Mean infarct differences (95% CIs) between each CTP software and FLAIR MRI for each cohort were: intervention cohort: RAPID=9.0±7.7 mL, Sphere=−0.2±8.7 mL, Vitrea=−7.9±8.9 mL; conservative treatment cohort: RAPID=−31.9±21.6 mL, Sphere=−26.8±17.4 mL, Vitrea=−15.3±13.7 mL. Overlap and Dice coefficients for predicted infarct were (overlap, Dice): intervention cohort: RAPID=(0.57, 0.44), Sphere=(0.68, 0.60), Vitrea=(0.70, 0.60); conservative treatment cohort: RAPID=(0.71, 0.56), Sphere=(0.73, 0.60), Vitrea=(0.72, 0.64).

Conclusions Sphere proved the most accurate in patients who had intervention infarct assessment as Vitrea and RAPID overestimated and underestimated infarct, respectively. Vitrea proved the most accurate in penumbra assessment for patients treated conservatively although all software overestimated penumbra.

  • brain
  • CT perfusion
  • stroke
  • MRI

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  • Contributors RAR, KVS, MM, MW, XZ, ARP, YH, and CNI conceived and designed the research. RAR, KVS, MW, ARP, ABA, JS, MMSB, JMD, EIL, and AHS collected and reviewed the data. RAR analyzed the data and performed the statistical analysis. CNI and JS handled the funding and supervision of the research. RAR drafted the manuscript. All authors made revisions to the manuscript and reviewed the final version.

  • Funding This research was funded by Canon Medical Systems USA, Inc.

  • Competing interests KVS: consulting for Canon Medical Systems Corporation, Penumbra Inc, Medtronic, Jacobs Institute; and co-founder of Neurovascular Diagnostics Inc. MM: consultant for Canon, Cerebrotech, Imperative care; and NIH grant support R21NS109575. YH: employee of Canon Medical Systems USA Inc. AHS: financial interest/investor/stock options/ownership in Amnis Therapeutics, Apama Medical, Blink TBI Inc, Buffalo Technology Partners Inc, Cardinal Consultants, Cerebrotech Medical Systems Inc, Cognition Medical, Endostream Medical Ltd, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics Inc, Q’Apel Medical Inc, Rebound Therapeutics Corp, Rist Neurovascular Inc, Serenity Medical Inc, Silk Road Medical, StimMed, Synchron, Three Rivers Medical Inc, Viseon Spine Inc; consultant/advisory board for Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA Inc, Cerebrotech Medical Systems Inc, Cerenovus, Corindus Inc, Endostream Medical Ltd, Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Northwest University–DSMB Chair for HEAT Trial, Penumbra, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp, Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical Inc, VasSol WL Gore and associates; principal investigator/steering comment of the following trials: Cerenovus NAPA and ARISE II; Medtronic SWIFT PRIME and SWIFT DIRECT; MicroVention FRED & CONFIDENCE; MUSC POSITIVE; Penumbra 3D Separator, COMPASS, INVEST; Davies-Research grant: National Center for Advancing Translational Sciences of the National Institutes of Health under award number KL2TR001413 to the University at Buffalo; speakers’ bureau for Penumbra; honoraria for Neurotrauma Science, LLC; and shareholder/ownership interests in RIST Neurovascular. EIL: shareholder/ownership interests in NeXtGen Biologics, RAPID Medical, Claret Medical, Cognition Medical, Imperative Care (formerly the Stroke Project), Rebound Therapeutics, StimMed, Three Rivers Medical; national principal investigator/steering committees for Medtronic (merged with Covidien Neurovascular) SWIFT Prime and SWIFT Direct Trials; honoraria from Medtronic (training); consultant for Claret Medical, GLG Consulting, Guidepoint Global, Imperative Care, Medtronic, Rebound, StimMed; advisory board for Stryker (AIS Clinical Advisory Board), NeXtGen Biologics, MEDX, Cognition Medical, Endostream Medical; and site principal investigator for CONFIDENCE study (MicroVention), STRATIS Study—Sub I (Medtronic). CNI: equipment grant from Canon Medical Systems and Cummings Foundation support.

  • Patient consent for publication Not required.

  • Ethics approval University at Buffalo Institutional Review Board approval was obtained and informed consent was waived for this Health Insurance Portability and Accountability Act compliant retrospective study. IRB study No: MOD00005807.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available upon reasonable request. The data is composed of deidentified participant data and can be obtained upon request from Dr. Ciprian N. Ionita at