Impact of Lesion Load Thresholds on Alberta Stroke Program Early Computed Tomographic Score in Diffusion-Weighted Imaging.

Julian Schröder, Bastian Cheng, Caroline Malherbe, Martin Ebinger, Martin Köhrmann, Ona Wu, Dong-Wha Kang, David S. Liebeskind, Thomas Tourdias, Oliver C. Singer, Bruce Campbell, Marie Luby, Steven Warach, Jens Fiehler, André Kemmling, Jochen B. Fiebach, Christian Gerloff, Götz Thomalla
Front. Neurol.. 2018-04-23; 9:
DOI: 10.3389/fneur.2018.00273

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Schröder J(1), Cheng B(1), Malherbe C(1)(2), Ebinger M(3)(4), Köhrmann M(5), Wu O(6), Kang DW(7), Liebeskind DS(8), Tourdias T(9), Singer OC(10), Campbell B(11), Luby M(12), Warach S(13), Fiehler J(14), Kemmling A(15), Fiebach JB(3), Gerloff C(1), Thomalla G(1).

Author information:
(1)Klinik und Poliklinik für Neurologie, Kopf- und Neurozentrum,
Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
(2)Institut für Computational Neuroscience, Universitätsklinikum
Hamburg-Eppendorf, Hamburg, Germany.
(3)Centrum für Schlaganfallforschung Berlin, Charité – Universitätsmedizin
Berlin, Berlin, Germany.
(4)Klinik für Neurologie, Charité – Universitätsmedizin Berlin, Berlin, Germany.
(5)Klinik für Neurologie, Universität Erlangen-Nürnberg, Erlangen, Germany.
(6)Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard Medical School, Boston, MA, United
(7)Department of Neurology, Asan Medical Center, University of Ulsan College of
Medicine, Seoul, South Korea.
(8)Neurovascular Imaging Research Core, Department of Neurology, University of
California, Los Angeles, Los Angeles, CA, United States.
(9)Service de Neuroimagerie Diagnostique de Thérapeutique, Centre Hospitalier
Universitaire de Bordeaux, Université de Bordeaux, Bordeaux, France.
(10)Klinik für Neurologie, Universitätsklinikum Frankfurt, Frankfurt, Germany.
(11)Department of Medicine and Neurology, Melbourne Brain Centre at the Royal
Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia.
(12)National Institute of Neurological Disorders and Stroke (NINDS), National
Institutes of Health (NIH), Bethesda, MD, United States.
(13)Department of Neurology, Dell Medical School, University of Texas at Austin,
Austin, TX, United States.
(14)Klinik und Poliklinik für Neuroradiologische Diagnostik und Intervention,
Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
(15)Institut für Neuroradiologie, Universitätsklinikum Schleswig-Holstein,
Lübeck, Germany.

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
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.


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