When to expect negative diffusion-weighted images in stroke and transient ischemic attack.
OBJECTIVE
The frequency of DWI negative cerebral ischemia and clinical factors associated with such a circumstance is not well understood.


METHODS
We performed MRI including diffusion-weighted imaging (DWI) in patients with stroke and transient ischemic attack (TIA) within 24 hours of symptom onset and again at 30 days.


RESULTS
Of 401 patients, 103 (25.6%) had an initial negative DWI study. In the DWI negative group, among the stroke patients, 6/26 (23.1%) had infarcts on follow-up MRI (4 lacunar and 2 posterior circulation syndromes) and 1 had a rMTT deficit. Among the TIA patients, 4/63 (6.3%) showed rMTT deficits and 2/63 (3.2%) had infarcts on follow-up MRI.


CONCLUSIONS
Baseline perfusion weighted imaging sequences may detect ischemia in a small proportion of DWI negative cases. Only those with brain stem location or lacunar syndrome were DWI negative initially and yet had a follow-up imaging confirmation of infarct or a final clinical diagnosis of stroke.
Sylaja
P N
PN
Calgary Stroke Program, Department of Clinical Neurosciences, Foothills Medical Centre, Room 1162, University of Calgary, Alberta, Canada.
Coutts
Shelagh B
SB
Krol
Andrea
A
Hill
Michael D
MD
Demchuk
Andrew M
AM
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D020520:Brain Infarction / Q000473:pathology / Q000503:physiopathology; D020526:Brain Stem Infarctions / Q000473:pathology / Q000503:physiopathology; D002536:Cerebral Arteries / Q000473:pathology* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards*; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology
D015415:Biomarkers