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

J Neurointerv Surg. 2021 Feb;13(2):130-135. doi: 10.1136/neurintsurg-2020-015966. Epub 2020 May 26.


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.

Keywords: CT perfusion; MRI; brain; stroke.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Brain Ischemia / diagnostic imaging*
  • Brain Ischemia / therapy
  • Cerebral Infarction / diagnostic imaging*
  • Cerebral Infarction / therapy
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Humans
  • Ischemic Stroke / diagnostic imaging*
  • Ischemic Stroke / therapy
  • Magnetic Resonance Imaging / methods
  • Magnetic Resonance Imaging / standards
  • Male
  • Middle Aged
  • Perfusion Imaging / methods
  • Perfusion Imaging / standards*
  • Reperfusion
  • Software / standards*
  • Tomography, X-Ray Computed / methods
  • Tomography, X-Ray Computed / standards*