The Prognostic Value of CT Angiography and CT Perfusion in Acute Ischemic Stroke.
BACKGROUND
CT angiography (CTA) and CT perfusion (CTP) are important diagnostic tools in acute ischemic stroke. We investigated the prognostic value of CTA and CTP for clinical outcome and determined whether they have additional prognostic value over patient characteristics and non-contrast CT (NCCT).


METHODS
We included 1,374 patients with suspected acute ischemic stroke in the prospective multicenter Dutch acute stroke study. Sixty percent of the cohort was used for deriving the predictors and the remaining 40% for validating them. We calculated the predictive values of CTA and CTP predictors for poor clinical outcome (modified Rankin Scale score 3-6). Associations between CTA and CTP predictors and poor clinical outcome were assessed with odds ratios (OR). Multivariable logistic regression models were developed based on patient characteristics and NCCT predictors, and subsequently CTA and CTP predictors were added. The increase in area under the curve (AUC) value was determined to assess the additional prognostic value of CTA and CTP. Model validation was performed by assessing discrimination and calibration.


RESULTS
Poor outcome occurred in 501 patients (36.5%). Each of the evaluated CTA measures strongly predicted outcome in univariable analyses: the positive predictive value (PPV) was 59% for Alberta Stroke Program Early CT Score (ASPECTS) ≤7 on CTA source images (OR 3.3; 95% CI 2.3-4.8), 63% for presence of a proximal intracranial occlusion (OR 5.1; 95% CI 3.7-7.1), 66% for poor leptomeningeal collaterals (OR 4.3; 95% CI 2.8-6.6), and 58% for a >70% carotid or vertebrobasilar stenosis/occlusion (OR 3.2; 95% CI 2.2-4.6). The same applied to the CTP measures, as the PPVs were 65% for ASPECTS ≤7 on cerebral blood volume maps (OR 5.1; 95% CI 3.7-7.2) and 53% for ASPECTS ≤7 on mean transit time maps (OR 3.9; 95% CI 2.9-5.3). The prognostic model based on patient characteristics and NCCT measures was highly predictive for poor clinical outcome (AUC 0.84; 95% CI 0.81-0.86). Adding CTA and CTP predictors to this model did not improve the predictive value (AUC 0.85; 95% CI 0.83-0.88). In the validation cohort, the AUC values were 0.78 (95% CI 0.73-0.82) and 0.79 (95% CI 0.75-0.83), respectively. Calibration of the models was satisfactory.


CONCLUSIONS
In patients with suspected acute ischemic stroke, admission CTA and CTP parameters are strong predictors of poor outcome and can be used to predict long-term clinical outcome. In multivariable prediction models, however, their additional prognostic value over patient characteristics and NCCT is limited in an unselected stroke population.
Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
Tom
T
van Seeters
Geert Jan
GJ
Biessels
L Jaap
LJ
Kappelle
Irene C
IC
van der Schaaf
Jan Willem
JW
Dankbaar
Alexander D
AD
Horsch
Joris M
JM
Niesten
Merel J
MJ
Luitse
Charles B
CB
Majoie
Jan Albert
JA
Vos
Wouter J
WJ
Schonewille
Marianne A
MA
van Walderveen
Marieke J
MJ
Wermer
Lucien E
LE
Duijm
Koos
K
Keizer
Joseph C
JC
Bot
Marieke C
MC
Visser
Aad
A
van der Lugt
Diederik W
DW
Dippel
F Oskar
FO
Kesselring
Jeannette
J
Hofmeijer
Geert J
GJ
Lycklama À Nijeholt
Jelis
J
Boiten
Willem Jan
WJ
van Rooij
Paul L
PL
de Kort
Yvo B
YB
Roos
Ewoud J
EJ
van Dijk
C Constantijn
CC
Pleiter
Willem P
WP
Mali
Yolanda
Y
van der Graaf
Birgitta K
BK
Velthuis
D000367:Age Factors; D000368:Aged; D019540:Area Under Curve; D001786:Blood Glucose / Q000032:analysis; D001925:Brain Damage, Chronic / Q000453:epidemiology / Q000209:etiology; D002545:Brain Ischemia / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007269:Injections, Intra-Arterial; D008297:Male; D008578:Meninges / Q000098:blood supply; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D055420:Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D011994:Recombinant Proteins / Q000627:therapeutic use; D012720:Severity of Illness Index; D017131:Thrombectomy; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
D001786:Blood Glucose; D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator