Wake-up stroke: clinical and neuroimaging characteristics.
BACKGROUND
Approximately 25% of ischemic stroke patients awaken with neurological deficits. In these patients, in whom the time from symptom onset is uncertain, brain imaging is a potential strategy to characterize the ischemia duration and the presence of salvageable brain tissue.


METHODS
We prospectively evaluated consecutive patients with acute ischemic stroke. CT angiography and CT perfusion (CTP) were performed in patients within 24 h of symptom onset. The patients were classified into 'known onset', 'indefinite onset but not on awakening' and 'wake-up stroke' groups.


RESULTS
Of 676 patients evaluated, 420 had known-onset strokes, 131 wake-up strokes and 125 strokes with an indefinite time of symptom onset. Ischemic lesion volumes were higher in patients with indefinite-onset strokes (p = 0.04). The frequencies of CTP mismatch and of large-vessel intracranial occlusions were similar among the groups (p = 0.9 and p = 0.2, respectively).


CONCLUSIONS
The considerable prevalence of CTP mismatch and of intracranial artery occlusions in our patients with wake-up strokes suggests that arterial and perfusion imaging might be particularly important in this population. Revised indications for thrombolysis by using imaging-based protocols might offer these patients the prospect of receiving acute stroke treatment even without a clear time of symptom onset.
Silva
Gisele S
GS
Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. giselesampaio @ hotmail.com
Lima
Fabricio O
FO
Camargo
Erica C S
EC
Smith
Wade S
WS
Singhal
Aneesh B
AB
Greer
David M
DM
Ay
Hakan
H
Lev
Michael H
MH
Harris
Gordon J
GJ
Halpern
Elkan F
EF
Sonni
Shruti
S
Koroshetz
Walter
W
Furie
Karen L
KL
D000368:Aged; D000369:Aged, 80 and over; D001925:Brain Damage, Chronic / Q000453:epidemiology / Q000209:etiology; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000473:pathology; D002533:Cerebral Angiography; D015331:Cohort Studies; D000075202:Contraindications; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging; D011379:Prognosis; D011446:Prospective Studies; D015424:Reperfusion; D012720:Severity of Illness Index; D016037:Single-Blind Method; D015912:Thrombolytic Therapy; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014851:Wakefulness
D005343:Fibrinolytic Agents