Early ischemic edema on cerebral computed tomography: its relation to diffusion changes and hypoperfusion within 6 h after human ischemic stroke. A comparison of CT, MRI and PET.
BACKGROUND
Brain tissue hypoattenuation on early computed tomography is frequently included in decision making in acute stroke management. However, its pathophysiological counterpart needs further evaluation.


METHODS
By comparative imaging with diffusion-weighted imaging and 15O-water positron emission tomography we aimed to interpret early (<6 h) hypoattenuation.


RESULTS
In 11 patients, the hypoattenuation corresponded to a decreased proton diffusion (median 115.9% relative DWI value) measured by magnetic resonance imaging and to a severe hypoperfusion (below 12 ml/100 g/ min) assessed by positron emission tomography. The volume of parenchymal hypoattenuation correlated to the tissue with disturbed diffusion (Spearman's rho=0.73), but largely underestimated the hypoperfusion below 20 ml/100 g/min.


CONCLUSIONS
Early hypoattenuation reflects the coupling of the severity of ischemia and resulting diffusion changes. It allows an estimate of the infarct core but underestimates the penumbral hypoperfusion.
Department of Neurology, University of Cologne, Cologne, Germany. j.sobesky@pet.mpin-koeln.mpg.de
Jan
J
Sobesky
Rüdiger
R
von Kummer
Monika
M
Frackowiak
Olivier
O
Zaro Weber
Fritz G
FG
Lehnhardt
Christian
C
Dohmen
Michael
M
Neveling
Walter
W
Möller-Hartmann
Andreas H
AH
Jacobs
Wolf-Dieter
WD
Heiss
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001929:Brain Edema / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D005500:Follow-Up Studies; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism*; D008875:Middle Aged; D049268:Positron-Emission Tomography; D013997:Time Factors; D014057:Tomography, X-Ray Computed