Perfusion-CT assessment of infarct core and penumbra: receiver operating characteristic curve analysis in 130 patients suspected of acute hemispheric stroke.
OBJECTIVE
Different definitions have been proposed to define the ischemic penumbra from perfusion-CT (PCT) data, based on parameters and thresholds tested only in small pilot studies. The purpose of this study was to perform a systematic evaluation of all PCT parameters (cerebral blood flow, volume [CBV], mean transit time [MTT], time-to-peak) in a large series of acute stroke patients, to determine which (combination of) parameters most accurately predicts infarct and penumbra.


METHODS
One hundred and thirty patients with symptoms suggesting hemispheric stroke < or =12 hours from onset were enrolled in a prospective multicenter trial. They all underwent admission PCT and follow-up diffusion-weighted imaging/fluid-attenuated inversion recovery (DWI/FLAIR); 25 patients also underwent admission DWI/FLAIR. PCT maps were assessed for absolute and relative reduced CBV, reduced cerebral blood flow, increased MTT, and increased time-to-peak. Receiver-operating characteristic curve analysis was performed to determine the most accurate PCT parameter, and the optimal threshold for each parameter, using DWI/FLAIR as the gold standard.


RESULTS
The PCT parameter that most accurately describes the tissue at risk of infarction in case of persistent arterial occlusion is the relative MTT (area under the curve=0.962), with an optimal threshold of 145%. The PCT parameter that most accurately describes the infarct core on admission is the absolute CBV (area under the curve=0.927), with an optimal threshold at 2.0 ml x 100 g(-1).


CONCLUSIONS
In a large series of 130 patients, the optimal approach to define the infarct and the penumbra is a combined approach using 2 PCT parameters: relative MTT and absolute CBV, with dedicated thresholds.
Wintermark
Max
M
Department of Radiology, University of California, San Francisco, CA 94143-0628, USA. Max.Wintermark@radiology.ucsf.edu
Flanders
Adam E
AE
Velthuis
Birgitta
B
Meuli
Reto
R
van Leeuwen
Maarten
M
Goldsher
Dorit
D
Pineda
Carissa
C
Serena
Joaquin
J
van der Schaaf
Irene
I
Waaijer
Annet
A
Anderson
James
J
Nesbit
Gary
G
Gabriely
Igal
I
Medina
Victoria
V
Quiles
Ana
A
Pohlman
Scott
S
Quist
Marcel
M
Schnyder
Pierre
P
Bogousslavsky
Julien
J
Dillon
William P
WP
Pedraza
Salvador
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume; D001921:Brain / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed