Identifying lesion growth with MR imaging in acute ischemic stroke.
OBJECTIVE
To determine whether different MR diffusion- and perfusion-weighted imaging (DWI and PWI) parameters are important in distinguishing lesion growth from the acute lesion and from oligemia.


METHODS
MR DWI and PWI were acquired from thirteen patients. We defined three regions: (i) LESION - intersection of acute and final lesions, (ii) GROWTH - portion of final lesion not part of acute lesion, and (iii) OLIGEMIA - region of perfusion abnormality not part of either the acute or final lesions. We used logistic regression modeling to distinguish GROWTH from LESION and from OLIGEMIA on a voxel-wise basis using DWI- and PWI-based parameters. Final models were selected based on the Wald statistic and validated by cross-validation using the mean (+/- standard deviation) area under the curve (AUC) from receiver operating characteristic analysis.


RESULTS
The final model for differentiating GROWTH from LESION included DWI, the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and tissue type (AUC = 0.939 +/- 0.028). The final model for differentiating GROWTH from OLIGEMIA included DWI, ADC, CBF, and time-to-peak (AUC = 0.793 +/- 0.106).


CONCLUSIONS
Different MR parameters are important in differentiating lesion growth from acute lesion and from oligemia in acute ischemic stroke.
Bristow
Michael S
MS
Department of Radiology, University of Calgary, Calgary, Alberta, Canada. msbristo@ucalgary.ca
Poulin
Brett W
BW
Simon
Jessica E
JE
Hill
Michael D
MD
Kosior
Jayme C
JC
Coutts
Shelagh B
SB
Frayne
Richard
R
Mitchell
J Ross
JR
Demchuk
Andrew M
AM
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019540:Area Under Curve; D002545:Brain Ischemia / Q000473:pathology*; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000473:pathology*