http://stroke.ahajournals.org/content/44/11/3084.abstract.html?etoc
- Shervin Kamalian, MD, MMSc*;
- Andre Kemmling, MD*;
- Roderick C. Borgie, MD;
- Livia T. Morais, MD;
- Seyedmehdi Payabvash, MD;
- Ana M. Franceschi, MD;
- Shahmir Kamalian, MD;
- Albert J. Yoo, MD;
- Karen L. Furie, MD, MPH;
- Michael H. Lev, MD, FAHA, FACR
+ Author Affiliations
- Correspondence to Michael H. Lev, MD, FAHA, FACR, Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Gray B241H, 55 Fruit St, Boston, MA 02114. E-mail mlev@partners.org
-
↵* Drs Kamalian and Kemmling contributed equally.
Abstract
Background and Purpose—Previous
univariate analyses have suggested that proximal middle cerebral artery
infarcts with insular involvement have greater
severity and are more likely to progress into
surrounding penumbral tissue at risk. We hypothesized that a practical,
simple
scoring method to assess percent insular
ribbon infarction (PIRI score) would improve prediction of penumbral
loss over other
common imaging biomarkers.
Methods—Of
consecutive acute stroke patients from 2003 to 2008, 45 with proximal
middle cerebral artery–only occlusion met inclusion
criteria, including available penumbral
imaging. Infarct (diffusion-weighted imaging), tissue at risk (magnetic
resonance
mean transit time), and final infarct volume
(magnetic resonance/computed tomography) were manually segmented.
Diffusion-weighted
imaging images were rated according to the
5-point PIRI score (0, normal; 1, <25%; 2, 25%–49%; 3, 50%–74%; 4,
≥75% insula
involvement). Percent mismatch loss was
calculated as an outcome measure of infarct progression. Receiver
operating characteristic
curve and multivariate analyses were
performed.
Results—Mean admission diffusion-weighted imaging infarct volume was 30.9 (±38.8) mL and median (interquartile range) PIRI score was
3 (0.75–4). PIRI score was significantly correlated with percent mismatch loss (P<0.0001). When percent mismatch loss was dichotomized based on its median value (30.0%), receiver operating characteristic
curve area under curve was 0.89 (P=0.0001)
with a 25% insula infarction optimal threshold. After adjusting for
time to imaging and treatment, binary logistic
regression, including dichotomized PIRI (25%
threshold), age, National Institutes of Health Stroke Scale score,
diffusion-weighted
imaging infarct volume, and computed
tomography angiography collateral score as covariates, revealed that
only dichotomized
insula score (P=0.03) and age (P=0.02)
were independent predictors of large (68.2%) versus small (8.1%)
mismatch loss. There was excellent interobserver agreement
for dichotomized PIRI scoring (κ=0.91).
Conclusions—Admission
insular infarction >25% is the strongest predictor of large mismatch
loss in this cohort of proximal middle cerebral
artery occlusive stroke. This outcome marker
may help to identify treatment-eligible patients who are in greatest
need of
rapid reperfusion therapy.
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