The value of apparent diffusion coefficient maps in early cerebral ischemia.
OBJECTIVE
Prediction of the regions of the ischemic penumbra that are likely to progress to infarction is of great clinical interest. Whether lowered apparent diffusion coefficient (ADC) values were present in the ischemic penumbra of patients presenting with acute ischemic stroke and were specific to regions of the penumbra that proceeded to infarction was investigated.


METHODS
Nineteen patients with hemispheric stroke of less than 6 hours' onset and with acute scans showing a perfusion lesion greater than a diffusion lesion (ischemic penumbra) were studied. Scans also were performed subacutely (days 3 to 5) and at outcome (day 90). The outcome scan was used to identify regions of the penumbra that proceeded to infarction.


RESULTS
The ADC ratios were significantly reduced (P <.00001) in regions of the penumbra that progressed to infarction on the outcome scan compared with those that remained normal. In regions that showed transition to infarction, the mean ADC ratios were typically 0.75 to 0.90.


CONCLUSIONS
Intermediate ADC values are present in the ischemic penumbra and are indicative of tissue at risk of infarction.
Desmond
P M
PM
Department of Radiology, Royal Melbourne Hospital and University of Melbourne, Parkville, Victoria 3050, Australia.
Lovell
A C
AC
Rawlinson
A A
AA
Parsons
M W
MW
Barber
P A
PA
Yang
Q
Q
Li
T
T
Darby
D G
DG
Gerraty
R P
RP
Davis
S M
SM
Tress
B M
BM
D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000175:diagnosis* / Q000503:physiopathology; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000503:physiopathology; D004058:Diffusion; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012306:Risk; D012680:Sensitivity and Specificity; D014022:Tissue Survival / Q000502:physiology