on April 17, 2008
Published online before print April 17, 2008, doi: 10.1161/STROKEAHA.107.497453
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Submitted on July 18, 2007
From the Calgary Stroke Program, Seaman Family MR Research Centre, Department of Clinical Neurosciences, University of Calgary, Alberta, Canada. * To whom correspondence should be addressed. E-mail: ademchuk{at}ucalgary.ca.
Background and Purpose—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.
Revised on October 28, 2007
Accepted on November 14, 2007
When to Expect Negative Diffusion-Weighted Images in Stroke and Transient Ischemic Attack
P. N. Sylaja MD;
Key words: magnetic resonance imaging • stroke • transient ischemic attack • diffusion-weighted imaging • cerebral ischemia