title: Complete early reversal of diffusion-weighted imaging hyperintensities after ischemic stroke is mainly limited to small embolic lesions.
abstract: OBJECTIVE
  Case reports have demonstrated complete early reversal of hyperintensities on diffusion-weighted imaging (DWI) after clinically diagnosed stroke. We aimed to investigate systematically the rate and characteristics of reversible diffusion hyperintensities (RDHs) in the first week after stroke.
  
  
  METHODS
  Patients with clinical diagnosis of an acute cerebrovascular event and evidence of ischemia on DWI were included. MRI scans were performed on admission, on the following day, and 4 to 7 days after onset of symptoms with DWI and fluid-attenuated inversion recovery. Baseline and follow-up DWIs were coregistered and examined for individual RDHs. Characteristics of patients and of hyperintensities associated with early reversal were identified.
  
  
  RESULTS
  We included 153 patients with a median National Institutes of Health Stroke Scale score of 4 (interquartile range, 2-8). In 3 patients (2%), MR images normalized completely. Thirty-seven patients (24%) displayed individual RDHs. Of 611 initial DWI hyperintensities, 97 (16%) reversed. Thirteen percent of the RDHs had corresponding abnormalities on fluid-attenuated inversion recovery images at the third measurement. Median size of the RDHs was 0.029 mL (interquartile range, 0.013-0.055). RDHs were associated with a multiple infarct pattern (odds ratio, 22.1; 95% confidence interval, 4.5-109.7) and symptomatic carotid stenosis (odds ratio, 5.5; 95% confidence interval, 1.4-21.5). Fifty-nine percent of the patients with RDHs had new additional lesions on follow-up DWI. RDHs were not associated with functional improvement on the National Institutes of Health Stroke Scale score.
  
  
  CONCLUSIONS
  In this population of mainly minor to moderate stroke patients, complete normalization of MR images was rare. Complete reversal of individual DWI hyperintensities was limited to very small lesions and mostly occurred in embolic stroke patients. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00715533.
authors: Department of Neurology, Charité Campus Benjamin Franklin, Berlin, Germany. fredrik.albach@charite.de
authors: Fredrik N
authors: FN
authors: Albach
authors: Peter
authors: P
authors: Brunecker
authors: Tatiana
authors: T
authors: Usnich
authors: Kersten
authors: K
authors: Villringer
authors: Martin
authors: M
authors: Ebinger
authors: Jochen B
authors: JB
authors: Fiebach
authors: Christian H
authors: CH
authors: Nolte
mesh_terms: D000368:Aged; D001921:Brain / Q000002:abnormalities / Q000473:pathology; D002545:Brain Ischemia / Q000473:pathology* / Q000628:therapy*; D002339:Carotid Arteries / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004617:Embolism / Q000628:therapy*; D005260:Female; D006801:Humans; D007511:Ischemia / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015607:Stents; D020521:Stroke / Q000473:pathology* / Q000628:therapy*; D015912:Thrombolytic Therapy