Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Cerebrovasc Dis 2012;33:248–254 DOI: 10.1159/000334665 Silent New DWI Lesions within the First Week after Stroke Christian H. Nolte a, b Fredrik N. Albach a Peter U. Heuschmann b Peter Brunecker b Kersten Villringer b Matthias Endres a, b Jochen B. Fiebach b a Department of Neurology, Charité Benjamin Franklin Campus, and b Center for Stroke Research Berlin, University Hospital Charité, Berlin, Germany tween first and second imaging (first interval) and 23.3% be- tween second and third imaging (second interval). In uni- variate analyses, thrombolysis and multiple lesion pattern were associated with new lesions within the first interval. Ip- silateral carotid stenosis, multiple lesion pattern, vessel re- canalization, atrial fibrillation, older age and higher NIHSS were associated with new lesions within the second interval. In multivariable analysis, ipsilateral carotid stenosis, recana- lization and multiple lesion pattern remained independent- ly associated with any new lesions. Conclusions: New DWI lesions occur more often than routine neurological examina- tion suggests. Thrombolysis was associated with very early new DWI lesions within the first interval, ipsilateral carotid stenosis and spontaneous recanalization with new DWI le- sions within the second interval. Copyright © 2012 S. Karger AG, Basel Introduction Recurrent stroke affects between 1 and 5% of stroke patients within the first week. The rate of stroke recur- rence in epidemiological studies is determined by evi- dence of new clinical symptoms in neurological exami- nation. However, used definitions vary across the studies, Key Words Silent stroke  Infarction  Diffusion-weighted imaging  New diffusion-weighted imaging lesions Abstract Background: The rate of cerebral infarct recurrence is deter- mined by clinical examination. Routine neurological exami- nation is less sensitive than cerebral imaging in detecting new cerebral lesions. We aimed to determine the rate of new diffusion-weighted imaging (DWI) lesions at 2 time points after stroke and to identify factors associated with them. Methods: Patients who were hospitalized with acute isch- emic stroke underwent DWI at 3 time points (within 24, 48 and 144 h after stroke onset, respectively). Scans were made anonymous and reviewed in a random order. Lesions on DWI were delineated manually by blinded investigators. Then, coregistered DWI templates were analyzed for new ischemic lesions on the corresponding follow-up DWI. New lesions had to be separate and lesion growth was not considered. Univariate and multivariable logistic regression analyses were performed to define predictors of new DWI lesions. Re- sults: A total of 159 patients were enrolled in the study. Clin- ical stroke recurrence was detected in 2.5% of patients. A new cerebral lesion was detected in 5.7% of patients be- Received: May 6, 2011 Accepted: October 21, 2011 Published online: January 19, 2012 Christian H. Nolte Department of Neurology, Charité, Campus Benjamin Franklin Hindenburgdamm 30 DE–12200 Berlin (Germany) Tel. +49 30 8445 2275, E-Mail christian.nolte  @  charite.de © 2012 S. Karger AG, Basel 1015–9770/12/0333–0248$38.00/0 Accessible online at: www.karger.com/ced