Impact of lesion load thresholds on Alberta stroke program early computed tomographic score in diffusion-weighted imaging

Götz Thomalla1 the STIR and VISTA Imaging Investigators

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Background and aims: Assessment of ischemic lesions on computed tomography or MRI diffusion-weighted imaging (DWI) using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is widely used to guide acute stroke treatment. However, it has never been defined how many voxels need to be affected to label a DWI-ASPECTS region ischemic. We aimed to assess the effect of various lesion load thresholds on DWI-ASPECTS and compare this automated analysis with visual rating. Materials and methods: We analyzed overlap of individual DWI lesions of 315 patients from the previously published predictive value of fluid-attenuated inversion recovery study with a probabilistic ASPECTS template derived from 221 CT images. We applied multiple lesion load thresholds per DWI-ASPECTS region (> 0, > 1, > 10, and > 20% in each DWI-ASPECTS region) to compute DWI-ASPECTS for each patient and compared the results to visual reading by an experienced stroke neurologist. Results: By visual rating, median ASPECTS was 9, 84 patients had a DWI-ASPECTS score ≤7. Mean DWI lesion volume was 22.1 (±35) ml. In contrast, by use of > 0, > 1-, > 10-, and > 20%-thresholds, median DWI-ASPECTS was 1, 5, 8, and 10; 97.1% (306), 72.7% (229), 41% (129), and 25.7% (81) had DWI-ASPECTS ≤7, respectively. Overall agreement between automated assessment and visual rating was low for every threshold used (> 0%: κw = 0.020 1%: κw = 0.151; 10%: κw = 0.386; 20% κw = 0.381). Agreement for dichotomized DWI-ASPECTS ranged from fair to substantial (≤7: > 10% κ = 0.48; > 20% κ = 0.45; ≤5: > 10% κ = 0.528; and > 20% κ = 0.695). Conclusion: Overall agreement between automated and the standard used visual scoring is low regardless of the lesion load threshold used. However, dichotomized scoring achieved more comparable results. Varying lesion load thresholds had a critical impact on patient selection by ASPECTS. Of note, the relatively low lesion volume and lack of patients with large artery occlusion in our cohort may limit generalizability of these findings.

Original languageEnglish (US)
Article number273
JournalFrontiers in Neurology
Volume9
Issue numberAPR
DOIs
StatePublished - Apr 23 2018

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Alberta
Stroke
Tomography
Diffusion Magnetic Resonance Imaging

Keywords

  • Acute stroke treatment
  • Alberta stroke program early computed tomography score
  • Computed tomography
  • Magnetic resonance imaging
  • Stroke

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

Cite this

Impact of lesion load thresholds on Alberta stroke program early computed tomographic score in diffusion-weighted imaging. / Götz Thomalla1 the STIR and VISTA Imaging Investigators.

In: Frontiers in Neurology, Vol. 9, No. APR, 273, 23.04.2018.

Research output: Contribution to journalArticle

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title = "Impact of lesion load thresholds on Alberta stroke program early computed tomographic score in diffusion-weighted imaging",
abstract = "Background and aims: Assessment of ischemic lesions on computed tomography or MRI diffusion-weighted imaging (DWI) using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is widely used to guide acute stroke treatment. However, it has never been defined how many voxels need to be affected to label a DWI-ASPECTS region ischemic. We aimed to assess the effect of various lesion load thresholds on DWI-ASPECTS and compare this automated analysis with visual rating. Materials and methods: We analyzed overlap of individual DWI lesions of 315 patients from the previously published predictive value of fluid-attenuated inversion recovery study with a probabilistic ASPECTS template derived from 221 CT images. We applied multiple lesion load thresholds per DWI-ASPECTS region (> 0, > 1, > 10, and > 20{\%} in each DWI-ASPECTS region) to compute DWI-ASPECTS for each patient and compared the results to visual reading by an experienced stroke neurologist. Results: By visual rating, median ASPECTS was 9, 84 patients had a DWI-ASPECTS score ≤7. Mean DWI lesion volume was 22.1 (±35) ml. In contrast, by use of > 0, > 1-, > 10-, and > 20{\%}-thresholds, median DWI-ASPECTS was 1, 5, 8, and 10; 97.1{\%} (306), 72.7{\%} (229), 41{\%} (129), and 25.7{\%} (81) had DWI-ASPECTS ≤7, respectively. Overall agreement between automated assessment and visual rating was low for every threshold used (> 0{\%}: κw = 0.020 1{\%}: κw = 0.151; 10{\%}: κw = 0.386; 20{\%} κw = 0.381). Agreement for dichotomized DWI-ASPECTS ranged from fair to substantial (≤7: > 10{\%} κ = 0.48; > 20{\%} κ = 0.45; ≤5: > 10{\%} κ = 0.528; and > 20{\%} κ = 0.695). Conclusion: Overall agreement between automated and the standard used visual scoring is low regardless of the lesion load threshold used. However, dichotomized scoring achieved more comparable results. Varying lesion load thresholds had a critical impact on patient selection by ASPECTS. Of note, the relatively low lesion volume and lack of patients with large artery occlusion in our cohort may limit generalizability of these findings.",
keywords = "Acute stroke treatment, Alberta stroke program early computed tomography score, Computed tomography, Magnetic resonance imaging, Stroke",
author = "{G{\"o}tz Thomalla1 the STIR and VISTA Imaging Investigators} and Julian Schr{\"o}der and Bastian Cheng and Caroline Malherbe and Martin Ebinger and Martin K{\"o}hrmann and Ona Wu and Kang, {Dong Wha} and Liebeskind, {David S.} and Thomas Tourdias and Singer, {Oliver C.} and Bruce Campbell and Marie Luby and Steven Warach and Jens Fiehler and Andr{\'e} Kemmling and Fiebach, {Jochen B.} and Christian Gerloff and Gregory Albers and Stephen Davis and Geoffrey Donnan and Marc Fisher and Anthony Furlan and James Grotta and Werner Hacke and Stella Kidwell and Walter Koroshetz and Lees, {Kennedy R.} and Michael Lev and Sorensen, {A. Gregory} and Vincent Thijs and G{\"o}tz Thomalla and Joanna Wardlaw and Max Wintermark",
year = "2018",
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journal = "Frontiers in Neurology",
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T1 - Impact of lesion load thresholds on Alberta stroke program early computed tomographic score in diffusion-weighted imaging

AU - Götz Thomalla1 the STIR and VISTA Imaging Investigators

AU - Schröder, Julian

AU - Cheng, Bastian

AU - Malherbe, Caroline

AU - Ebinger, Martin

AU - Köhrmann, Martin

AU - Wu, Ona

AU - Kang, Dong Wha

AU - Liebeskind, David S.

AU - Tourdias, Thomas

AU - Singer, Oliver C.

AU - Campbell, Bruce

AU - Luby, Marie

AU - Warach, Steven

AU - Fiehler, Jens

AU - Kemmling, André

AU - Fiebach, Jochen B.

AU - Gerloff, Christian

AU - Albers, Gregory

AU - Davis, Stephen

AU - Donnan, Geoffrey

AU - Fisher, Marc

AU - Furlan, Anthony

AU - Grotta, James

AU - Hacke, Werner

AU - Kidwell, Stella

AU - Koroshetz, Walter

AU - Lees, Kennedy R.

AU - Lev, Michael

AU - Sorensen, A. Gregory

AU - Thijs, Vincent

AU - Thomalla, Götz

AU - Wardlaw, Joanna

AU - Wintermark, Max

PY - 2018/4/23

Y1 - 2018/4/23

N2 - Background and aims: Assessment of ischemic lesions on computed tomography or MRI diffusion-weighted imaging (DWI) using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is widely used to guide acute stroke treatment. However, it has never been defined how many voxels need to be affected to label a DWI-ASPECTS region ischemic. We aimed to assess the effect of various lesion load thresholds on DWI-ASPECTS and compare this automated analysis with visual rating. Materials and methods: We analyzed overlap of individual DWI lesions of 315 patients from the previously published predictive value of fluid-attenuated inversion recovery study with a probabilistic ASPECTS template derived from 221 CT images. We applied multiple lesion load thresholds per DWI-ASPECTS region (> 0, > 1, > 10, and > 20% in each DWI-ASPECTS region) to compute DWI-ASPECTS for each patient and compared the results to visual reading by an experienced stroke neurologist. Results: By visual rating, median ASPECTS was 9, 84 patients had a DWI-ASPECTS score ≤7. Mean DWI lesion volume was 22.1 (±35) ml. In contrast, by use of > 0, > 1-, > 10-, and > 20%-thresholds, median DWI-ASPECTS was 1, 5, 8, and 10; 97.1% (306), 72.7% (229), 41% (129), and 25.7% (81) had DWI-ASPECTS ≤7, respectively. Overall agreement between automated assessment and visual rating was low for every threshold used (> 0%: κw = 0.020 1%: κw = 0.151; 10%: κw = 0.386; 20% κw = 0.381). Agreement for dichotomized DWI-ASPECTS ranged from fair to substantial (≤7: > 10% κ = 0.48; > 20% κ = 0.45; ≤5: > 10% κ = 0.528; and > 20% κ = 0.695). Conclusion: Overall agreement between automated and the standard used visual scoring is low regardless of the lesion load threshold used. However, dichotomized scoring achieved more comparable results. Varying lesion load thresholds had a critical impact on patient selection by ASPECTS. Of note, the relatively low lesion volume and lack of patients with large artery occlusion in our cohort may limit generalizability of these findings.

AB - Background and aims: Assessment of ischemic lesions on computed tomography or MRI diffusion-weighted imaging (DWI) using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is widely used to guide acute stroke treatment. However, it has never been defined how many voxels need to be affected to label a DWI-ASPECTS region ischemic. We aimed to assess the effect of various lesion load thresholds on DWI-ASPECTS and compare this automated analysis with visual rating. Materials and methods: We analyzed overlap of individual DWI lesions of 315 patients from the previously published predictive value of fluid-attenuated inversion recovery study with a probabilistic ASPECTS template derived from 221 CT images. We applied multiple lesion load thresholds per DWI-ASPECTS region (> 0, > 1, > 10, and > 20% in each DWI-ASPECTS region) to compute DWI-ASPECTS for each patient and compared the results to visual reading by an experienced stroke neurologist. Results: By visual rating, median ASPECTS was 9, 84 patients had a DWI-ASPECTS score ≤7. Mean DWI lesion volume was 22.1 (±35) ml. In contrast, by use of > 0, > 1-, > 10-, and > 20%-thresholds, median DWI-ASPECTS was 1, 5, 8, and 10; 97.1% (306), 72.7% (229), 41% (129), and 25.7% (81) had DWI-ASPECTS ≤7, respectively. Overall agreement between automated assessment and visual rating was low for every threshold used (> 0%: κw = 0.020 1%: κw = 0.151; 10%: κw = 0.386; 20% κw = 0.381). Agreement for dichotomized DWI-ASPECTS ranged from fair to substantial (≤7: > 10% κ = 0.48; > 20% κ = 0.45; ≤5: > 10% κ = 0.528; and > 20% κ = 0.695). Conclusion: Overall agreement between automated and the standard used visual scoring is low regardless of the lesion load threshold used. However, dichotomized scoring achieved more comparable results. Varying lesion load thresholds had a critical impact on patient selection by ASPECTS. Of note, the relatively low lesion volume and lack of patients with large artery occlusion in our cohort may limit generalizability of these findings.

KW - Acute stroke treatment

KW - Alberta stroke program early computed tomography score

KW - Computed tomography

KW - Magnetic resonance imaging

KW - Stroke

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